Airplane Flying Handbook

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Ch 15.qxd 5/7/04 10:22 AM Page 15-4 15-5 piston from idle to full power is relatively rapid, somewhere on the order of 3 to 4 seconds. The acceleration on the different jet engines can vary considerably, but it is usually much slower. Efficiency in a jet engine is highest at high r.p.m. where the compressor is working closest to its optimum conditions. At low r.p.m. the operating cycle is generally inefficient. If the engine is operating at normal approach r.p.m. and there is a sudden requirement for increased thrust, the jet engine will respond immediately and full thrust can be achieved in about 2 seconds. However, at a low r.p.m., sudden full power application will tend to overfuel the engine resulting in possible compressor surge, excessive turbine temperatures, compressor stall and/or flameout. To prevent this, various limiters such as compressor bleed valves are contained in the system and serve to restrict the engine until it is at an r.p.m. at which it can respond to a rapid acceleration demand without distress. This critical r.p.m. is most noticeable when the engine is at idle r.p.m. and the thrust lever is rapidly advanced to a high power position. Engine acceleration is initially very slow, but changes to very fast after about 78 percent r.p.m. is reached. [Figure 15-7] Even though engine acceleration is nearly instantaneous after about 78 percent r.p.m., total time to accelerate from idle r.p.m. to full power may take as much as 8 seconds. For this reason, most jets are operated at a relatively high r.p.m. during the final approach to landing or at any other time that immediate power may be needed. JET ENGINE EFFICIENCY Maximum operating altitudes for general aviation turbojet airplanes now reach 51,000 feet. The efficiency of the jet engine at high altitudes is the primary reason for operating in the high altitude environment. The specific fuel consumption of jet engines decreases as the outside air temperature decreases for constant engine r.p.m. and true airspeed (TAS). Thus, by flying at a high altitude, the pilot is able to operate at flight levels where fuel economy is best and with the most advantageous cruise speed. For efficiency, jet airplanes are typically operated at high altitudes where cruise is usually very close to r.p.m or exhaust gas temperature limits. At high altitudes, little excess thrust may be available for maneuvering. Therefore, it is often impossible for the jet airplane to climb and turn simultaneously, and all maneuvering must be accomplished within the limits of available thrust and without sacrificing stability and controllability. ABSENCE OF PROPELLER EFFECT The absence of a propeller has a significant effect on the operation of jet powered airplanes that the transitioning pilot must become accustomed to. The effect is due to the absence of lift from the propeller slipstream, and the absence of propeller drag. ABSENCE OF PROPELLER SLIPSTREAM A propeller produces thrust by accelerating a large mass of air rearwards, and (especially with wing mounted engines) this air passes over a comparatively large percentage of the wing area. On a propeller driven airplane, the lift that the wing develops is the sum of the lift generated by the wing area not in the wake of the propeller (as a result of airplane speed) and the lift generated by the wing area influenced by the propeller slipstream. By increasing or decreasing the speed of the slipstream air, therefore, it is possible to increase or decrease the total lift on the wing without changing airspeed. 100 90 80 70 60 50 40 30 20 10 0 0 10 20 30 40 50 60 70 80 90 100 Percent Maximum Thrust Percent Maximum R.P.M. VARIATION OF THRUST WITH R.P.M. (Constant Altitude & Velocity) Figure 15-6.Variation of thrust with r.p.m. 8 6 4 2 60% 100% Time to Achieve Full Thrust (sec.) R.P.M. 78% Figure 15-7.Typical Jet engine acceleration times. Ch 15.qxd 5/7/04 10:22 AM Page 15-5 15-6 For example, a propeller driven airplane that is allowed to become too low and too slow on an approach is very responsive to a quick blast of power to salvage the situation. In addition to increasing lift at a constant airspeed, stalling speed is reduced with power on. Ajet engine, on the other hand, also produces thrust by accelerating a mass of air rearward, but this air does not pass over the wings. There is therefore no lift bonus at increased power at constant airspeed, and no significant lowering of power-on stall speed. In not having propellers, the jet powered airplane is minus two assets. • It is not possible to produce increased lift instantly by simply increasing power. • It is not possible to lower stall speed by simply increasing power. The 10-knot margin (roughly the difference between power-off and power-on stall speed on a propeller driven airplane for a given configuration) is lost. Add the poor acceleration response of the jet engine and it becomes apparent that there are three ways in which the jet pilot is worse off than the propeller pilot. For these reasons, there is a marked difference between the approach qualities of a piston engine airplane and a jet. In a piston engine airplane, there is some room for error. Speed is not too critical and a burst of power will salvage an increasing sink rate. In a jet, however, there is little room for error. If an increasing sink rate develops in a jet, the pilot must remember two points in the proper sequence. 1. Increased lift can be gained only by accelerating airflow over the wings, and this can be accomplished only by accelerating the entire airplane. 2. The airplane can be accelerated, assuming altitude loss cannot be afforded, only by a rapid increase in thrust, and here, the slow acceleration of the jet engine (possibly up to 8 seconds) becomes a factor. Salvaging an increasing sink rate on an approach in a jet can be a very difficult maneuver. The lack of ability to produce instant lift in the jet, along with the slow acceleration of the engine, necessitates a “stabilized approach” to a landing where full landing configuration, constant airspeed, controlled rate of descent, and relatively high power settings are maintained until over the threshold of the runway. This allows for almost immediate response from the engine in making minor changes in the approach speed or rate of descent and makes it possible to initiate an immediate go-around or missed approach if necessary. ABSENCE OF PROPELLER DRAG When the throttles are closed on a piston powered airplane, the propellers create a vast amount of drag, and airspeed is immediately decreased or altitude lost. The effect of reducing power to idle on the jet engine, however, produces no such drag effect. In fact, at an idle power setting, the jet engine still produces forward thrust. The main advantage is that the jet pilot is no longer faced with a potential drag penalty of a runaway propeller, or a reversed propeller. A disadvantage, however, is the “free wheeling” effect forward thrust at idle has on the jet. While this occasionally can be used to advantage (such as in a long descent), it is a handicap when it is necessary to lose speed quickly, such as when entering a terminal area or when in a landing flare. The lack of propeller drag, along with the aerodynamically clean airframe of the jet, are new to most pilots, and slowing the airplane down is one of the initial problems encountered by pilots transitioning into jets. SPEED MARGINS The typical piston powered airplane had to deal with two maximum operating speeds. • VNO—Maximum structural cruising speed, represented on the airspeed indicator by the upper limit of the green arc. It is, however, permissible to exceed VNO and operate in the caution range (yellow arc) in certain flight conditions. • VNE—Never-exceed speed, represented by a red line on the airspeed indicator. These speed margins in the piston airplanes were never of much concern during normal operations because the high drag factors and relatively low cruise power settings kept speeds well below these maximum limits. Maximum speeds in jet airplanes are expressed differently, and always define the maximum operating speed of the airplane which is comparable to the VNE of the piston airplane. These maximum speeds in a jet airplane are referred to as: • VMO—Maximum operating speed expressed in terms of knots. • MMO—Maximum operating speed expressed in terms of a decimal of Mach speed (speed of sound). To observe both limits VMO and MMO, the pilot of a jet airplane needs both an airspeed indicator and a Machmeter, each with appropriate red lines. In some general aviation jet airplanes, these are combined into Ch 15.qxd 5/7/04 10:22 AM Page 15-6 15-7 a single instrument that contains a pair of concentric indicators, one for the indicated airspeed and the other for indicated Mach number. Each is provided with an appropriate red line. [Figure 15-8] A more sophisticated indicator is used on most jetliners. It looks much like a conventional airspeed indicator but has a “barber pole” that automatically moves so as to display the applicable speed limit at all times. Because of the higher available thrust and very low drag design, the jet airplane can very easily exceed its speed margin even in cruising flight, and in fact in some airplanes in a shallow climb. The handling qualities in a jet can change drastically when the maximum operating speeds are exceeded. High speed airplanes designed for subsonic flight are limited to some Mach number below the speed of sound to avoid the formation of shock waves that begin to develop as the airplane nears Mach 1.0. These shock waves (and the adverse effects associated with them) can occur when the airplane speed is substantially below Mach 1.0. The Mach speed at which some portion of the airflow over the wing first equals Mach 1.0 is termed the critical Mach number (MACHCRIT). This is also the speed at which a shock wave first appears on the airplane. There is no particular problem associated with the acceleration of the airflow up to the point where Mach 1.0 is encountered; however, a shock wave is formed at the point where the airflow suddenly returns to subsonic flow. This shock wave becomes more severe and moves aft on the wing as speed of the wing is increased, and eventually flow separation occurs behind the well-developed shock wave. [Figure 15-9] If allowed to progress well beyond the MMO for the airplane, this separation of air behind the shock wave can result in severe buffeting and possible loss of control or “upset.” Because of the changing center of lift of the wing resulting from the movement of the shock wave, the pilot will experience pitch change tendencies as the airplane moves through the transonic speeds up to and exceeding MMO. [Figure 15-10] For example, as the graph in figure 15-10 illustrates, initially as speed is increased up to Mach .72 the wing develops an increasing amount of lift requiring a nosedown force or trim to maintain level flight. With increased speed and the aft movement of the shock wave, the wing’s center of pressure also moves aft causing the start of a nosedown tendency or “tuck.” By Mach .83 the nosedown forces are well developed to a point where a total of 70 pounds of back pressure are required to hold the nose up. If allowed to progress unchecked, Mach tuck may eventually occur. Although Mach tuck develops gradually, if it is Figure 15-8. Jet airspeed indicator. M=.72 (Critical Mach Number) M=.77 Supersonic Flow M=.82 Normal Shock Wave Subsonic Possible Separation Supersonic Flow Normal Shock Normal Shock Separation Maximum Local Velocity Is Less Than Sonic Figure 15-9.Transonic flow patterns. 70 60 50 40 30 20 10 0 10 20 0 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Stick Force in Pounds Mach Number Pull Push Figure 15-10. Example of Stick Forces vs. Mach Number in a typical jet airplane. Ch 15.qxd 5/7/04 10:22 AM Page 15-7 15-8 allowed to progress significantly, the center of pressure can move so far rearward that there is no longer enough elevator authority available to counteract it, and the airplane could enter a steep, sometimes unrecoverable dive. An alert pilot would have observed the high airspeed indications, experienced the onset of buffeting, and responded to aural warning devices long before encountering the extreme stick forces shown. However, in the event that corrective action is not taken and the nose allowed to drop, increasing airspeed even further, the situation could rapidly become dangerous. As the Mach speed increases beyond the airplane’s MMO, the effects of flow separation and turbulence behind the shock wave become more severe. Eventually, the most powerful forces causing Mach tuck are a result of the buffeting and lack of effective downwash on the horizontal stabilizer because of the disturbed airflow over the wing. This is the primary reason for the development of the T-tail configuration on some jet airplanes, which places the horizontal stabilizer as far as practical from the turbulence of the wings. Also, because of the critical aspects of high-altitude/high-Mach flight, most jet airplanes capable of operating in the Mach speed ranges are designed with some form of trim and autopilot Mach compensating device (stick puller) to alert the pilot to inadvertent excursions beyond its certificated MMO. RECOVERY FROM OVERSPEED CONDITIONS The simplest remedy for an overspeed condition is to ensure that the situation never occurs in the first place. For this reason, the pilot must be aware of all the conditions that could lead to exceeding the airplane’s maximum operating speeds. Good attitude instrument flying skills and good power control are essential. The pilot should be aware of the symptoms that will be experienced in the particular airplane as the VMO or MMO is being approached. These may include: • Nosedown tendency and need for back pressure or trim. • Mild buffeting as airflow separation begins to occur after critical Mach speed. • Actuation of an aural warning device/stick puller at or just slightly beyond VMO or MMO. The pilot’s response to an overspeed condition should be to immediately slow the airplane by reducing the power to flight idle. It will also help to smoothly and easily raise the pitch attitude to help dissipate speed (in fact this is done automatically through the stick puller device when the high speed warning system is activated). The use of speed brakes can also aid in slowing the airplane. If, however, the nosedown stick forces have progressed to the extent that they are excessive, some speed brakes will tend to further aggravate the nosedown tendency. Under most conditions, this additional pitch down force is easily controllable, and since speed brakes can normally be used at any speed, they are a very real asset. A final option would be to extend the landing gear. This will create enormous drag and possibly some noseup pitch, but there is usually little risk of damage to the gear itself. The pilot transitioning into jet airplanes must be familiar with the manufacturers’ recommended procedures for dealing with overspeed conditions contained in the FAA-approved Airplane Flight Manual for the particular make and model airplane. MACH BUFFET BOUNDARIES Thus far, only the Mach buffet that results from excessive speed has been addressed. The transitioning pilot, however, should be aware that Mach buffet is a function of the speed of the airflow over the wing— not necessarily the airspeed of the airplane. Anytime that too great a lift demand is made on the wing, whether from too fast an airspeed or from too high an angle of attack near the MMO, the “high speed buffet” will occur. However, there are also occasions when the buffet can be experienced at much slower speeds known as “low speed Mach buffet.” The most likely situations that could cause the low speed buffet would be when an airplane is flown at too slow a speed for its weight and altitude causing a high angle of attack. This very high angle of attack would have the same effect of increasing airflow over the upper surface of the wing to the point that all of the same effects of the shock waves and buffet would occur as in the high speed buffet situation. The angle of attack of the wing has the greatest effect on inducing the Mach buffet at either the high or low speed boundaries for the airplane. The conditions that increase the angle of attack, hence the speed of the airflow over the wing and chances of Mach buffet are: • High altitudes—The higher the airplane flies, the thinner the air and the greater the angle of attack required to produce the lift needed to maintain level flight. • Heavy weights—The heavier the airplane, the greater the lift required of the wing, and all other things being equal, the greater the angle of attack. • “G” loading—An increase in the “G” loading of the wing results in the same situation as increasing the weight of the airplane. It makes Ch 15.qxd 5/7/04 10:22 AM Page 15-8 15-9 no difference whether the increase in “G” forces is caused by a turn, rough control usage, or turbulence. The effect of increasing the wing’s angle of attack is the same. An airplane’s indicated airspeed decreases in relation to true airspeed as altitude increases. As the indicated airspeed decreases with altitude, it progressively merges with the low speed buffet boundary where prestall buffet occurs for the airplane at a load factor of 1.0 G. The point where the high speed Mach indicated airspeed and low speed buffet boundary indicated airspeed merge is the airplane’s absolute or aerodynamic ceiling. Once an airplane has reached its aerodynamic ceiling, which is higher than the altitude stipulated in the FAA-approved Airplane Flight Manual, the airplane can neither be made to go faster without activating the design stick puller at Mach limit nor can it be made to go slower without activating the stick shaker or stick pusher. This critical area of the airplane’s flight envelope is known as “coffin corner.” Mach buffet occurs as a result of supersonic airflow on the wing. Stall buffet occurs at angles of attack that produce airflow disturbances (burbling) over the upper surface of the wing which decreases lift. As density altitude increases, the angle of attack that is required to produce an airflow disturbance over the top of the wing is reduced until the density altitude is reached where Mach buffet and stall buffet converge (coffin corner). When this phenomenon is encountered, serious consequences may result causing loss of airplane control. Increasing either gross weight or load factor (G factor) will increase the low speed buffet and decrease Mach buffet speeds. A typical jet airplane flying at 51,000 feet altitude at 1.0 G may encounter Mach buffet slightly above the airplane’s MMO (.82 Mach) and low speed buffet at .60 Mach. However, only 1.4 G (an increase of only 0.4 G) may bring on buffet at the optimum speed of .73 Mach and any change in airspeed, bank angle, or gust loading may reduce this straightand- level flight 1.4 G protection to no protection at all. Consequently, a maximum cruising flight altitude must be selected which will allow sufficient buffet margin for necessary maneuvering and for gust conditions likely to be encountered. Therefore, it is important for pilots to be familiar with the use of charts showing cruise maneuver and buffet limits. [Figure 15-11] The transitioning pilot must bear in mind that the maneuverability of the jet airplane is particularly critical, especially at the high altitudes. Some jet airplanes have a very narrow span between the high and low speed buffets. One airspeed that the pilot should have firmly fixed in memory is the manufacturer’s recommended gust penetration speed for the particular make and model airplane. This speed is normally the speed that would give the greatest margin between the high and low speed buffets, and may be considerably higher 1 2 3 .1 .2 .3 .4 .5 .6 .7 .8 Load Factor – G Indicated Mach Number Sea Level 5,000 10,000 15,000 20,000 Pressure Altitude – 25,000 Ft. 30,000 35,000 40,00040,000 45,00045,000 MMO 19,000 Lbs. 11,000 18,000 17,000 16,000 15,000 14,000 13,000 12,000 A C B D Figure 15-11. Mach buffet boundary chart. Ch 15.qxd 5/7/04 10:22 AM Page 15-9 15-10 than design maneuvering speed (VA). This means that, unlike piston airplanes, there are times when a jet airplane should be flown in excess of VA during encounters with turbulence. Pilots operating airplanes at high speeds must be adequately trained to operate them safely. This training cannot be complete until pilots are thoroughly educated in the critical aspects of the aerodynamic factors pertinent to Mach flight at high altitudes. LOW SPEED FLIGHT The jet airplane wing, designed primarily for high speed flight, has relatively poor low speed characteristics. As opposed to the normal piston powered airplane, the jet wing has less area, a lower aspect ratio (long chord/short span), and thin airfoil shape—all of which amount to less lift. The sweptwing is additionally penalized at low speeds because the effective lift, which is perpendicular to the leading edge, is always less than the airspeed of the airplane itself. In other words, the airflow on the sweptwing has the effect of persuading the wing into believing that it is flying slower than it actually is, but the wing consequently suffers a loss of lift for a given airspeed at a given angle of attack. The first real consequence of poor lift at low speeds is a high stall speed. The second consequence of poor lift at low speeds is the manner in which lift and drag vary with speed in the lower ranges. As a jet airplane is slowed toward its minimum drag speed (VMD or L/DMAX), total drag increases at a much greater rate than lift, resulting in a sinking flightpath. If the pilot attempts to increase lift by increasing pitch attitude, airspeed will be further reduced resulting in a further increase in drag and sink rate as the airplane slides up the back side of the power curve. The sink rate can be arrested in one of two ways: • Pitch attitude can be substantially reduced to reduce the angle of attack and allow the airplane to accelerate to a speed above VMD, where steady flight conditions can be reestablished. This procedure, however, will invariably result in a substantial loss of altitude. • Thrust can be increased to accelerate the airplane to a speed above VMD to reestablish steady flight conditions. It should be remembered that the amount of thrust required will be quite large. The amount of thrust must be sufficient to accelerate the airplane and regain altitude lost. Also, if the airplane has slid a long way up the back side of the power required (drag) curve, drag will be very high and a very large amount of thrust will be required. In a typical piston engine airplane, VMD in the clean configuration is normally at a speed of about 1.3 VS. [Figure 15-12] Flight below VMD on a piston engine airplane is well identified and predictable. In contrast, in a jet airplane flight in the area of VMD (typically 1.5 – 1.6 VS) does not normally produce any noticeable changes in flying qualities other than a lack of speed stability—a condition where a decrease in speed leads to an increase in drag which leads to a further decrease in speed and hence a speed divergence. A pilot who is not cognizant of a developing speed divergence may find a serious sink rate developing at a constant power setting, and a pitch attitude that appears to be normal. The fact that drag increases more rapidly than lift, causing a sinking flightpath, is one of the most important aspects of jet airplane flying qualities. STALLS The stalling characteristics of the sweptwing jet airplane can vary considerably from those of the Minimum Power Required L/DMAX Figure 15-12. Thrust and power required curves. Ch 15.qxd 5/7/04 10:22 AM Page 15-10 15-11 normal straight wing airplane. The greatest difference that will be noticeable to the pilot is the lift developed vs. angle of attack. An increase in angle of attack of the straight wing produces a substantial and constantly increasing lift vector up to its maximum coefficient of lift, and soon thereafter flow separation (stall) occurs with a rapid deterioration of lift. By contrast, the sweptwing produces a much more gradual buildup of lift with no well defined maximum coefficient and has the ability to fly well beyond this maximum buildup even though lift is lost. The drag curves (which are not depicted in figure 15-13) are approximately the reverse of the lift curves shown, in that a rapid increase in drag component may be expected with an increase in the angle of attack of a sweptwing airplane. The differences in the stall characteristics between a conventional straight wing/low tailplane (non T-tail) airplane and a sweptwing T-tail airplane center around two main areas. • The basic pitching tendency of the airplane at the stall. • Tail effectiveness in stall recovery. On a conventional straight wing/low tailplane airplane, the weight of the airplane acts downwards forward of the lift acting upwards, producing a need for a balancing force acting downwards from the tailplane. As speed is reduced by gentle up elevator deflection, the static stability of the airplane causes a nosedown tendency. This is countered by further up elevator to keep the nose coming up and the speed decreasing. As the pitch attitude increases, the low set tail is immersed in the wing wake, which is slightly turbulent, low energy air. The accompanying aerodynamic buffeting serves as a warning of impending stall. The reduced effectiveness of the tail prevents the pilot from forcing the airplane into a deeper stall. [Figure 15-14] The conventional straight wing airplane conforms to the familiar nosedown pitching tendency at the stall and gives the entire airplane a fairly pronounced nosedown pitch. At the moment of stall, the wing wake passes more or less straight rearward and passes above the tail. The tail is now immersed in high energy air where it experiences a sharp increase in positive angle of attack causing upward lift. This lift then assists the nosedown pitch and decrease in wing angle of attack essential to stall recovery. In a sweptwing jet with a T-tail and rear fuselage mounted engines, the two qualities that are different from its straight wing low tailplane counterpart are the pitching tendency of the airplane as the stall develops and the loss of tail effectiveness at the stall. The handling qualities down to the stall are much the same as the straight wing airplane except that the high, T-tail remains clear of the wing wake and provides little or no warning in the form of a pre-stall buffet. Also, the tail is fully effective during the speed reduction towards the stall, and remains effective even after the wing has begun to stall. This enables the pilot to drive the wing into a deeper stall at a much greater angle of attack. At the stall, two distinct things happen. After the stall, the sweptwing T-tail airplane tends to pitch up rather than down, and the T-tail is immersed in the wing wake, which is low energy turbulent air. This greatly reduces tail effectiveness and the airplane’s ability to counter the noseup pitch. Also, the disturbed, relatively slow air behind the wing may sweep across the tail at such a large angle that the tail itself stalls. If this occurs, the pilot loses all pitch control and will be unable to lower the nose. The pitch up just after the stall is worsened by large reduction in lift and a large increase in drag, which causes a rapidly increasing Lift Coefficient Angle of Attack Straight Wing Sweptwing Figure 15-13. Stall vs. angle of attack—sweptwing vs. straight wing. Figure 15-14. Stall progression—typical straight wing airplane. Ch 15.qxd 5/7/04 10:22 AM Page 15-11 15-12 descent path, thus compounding the rate of increase of the wing’s angle of attack. [Figure 15-15] The pitch up tendency after the stall is a characteristic of a swept and/or tapered wings. With these types of wings, there is a tendency for the wing to develop a strong spanwise airflow towards the wingtip when the wing is at high angles of attack. This leads to a tendency for separation of airflow, and the subsequent stall, to occur at the wingtips first. [Figure 15-16] The tip first stall, results in a shift of the center of lift of the wing in a forward direction relative to the center of gravity of the airplane, causing the nose to pitch up. Another disadvantage of a tip first stall is that it can involve the ailerons and erode roll control. As previously stated, when flying at a speed in the area of VMD, an increase in angle of attack causes drag to increase faster than lift and the airplane begins to sink. It is essential to understand that this increasing sinking tendency, at a constant pitch attitude, results in a rapid increase in angle of attack as the flightpath becomes deflected downwards. [Figure 15-17] Furthermore, once the stall has developed and a large amount of lift has been lost, the airplane will begin to sink rapidly and this will be accompanied by a corresponding rapid increase in angle of attack. This is the beginning of what is termed a deep stall. As an airplane enters a deep stall, increasing drag reduces forward speed to well below normal stall speed. The sink rate may increase to many thousands of feet per minute. The airplane eventually stabilizes in a vertical descent. The angle of attack may approach Pre-Stall Stall Figure 15-15. Stall progression sweptwing airplane. Spanwise Flow of Boundary Layer Develops at High CL Initial Flow Separation at or Near Tip Area of Tip Stall Enlarges Stall Area Progresses Inboard Figure 15-16. Sweptwing stall characteristics. Ch 15.qxd 5/7/04 10:22 AM Page 15-12 15-13 90° and the indicated airspeed may be reduced to zero. At a 90° angle of attack, none of the airplane’s control surfaces are effective. It must be emphasized that this situation can occur without an excessively nose-high pitch attitude. On some airplanes, it can occur at an apparently normal pitch attitude, and it is this quality that can mislead the pilot because it appears similar to the beginning of a normal stall recovery. Deep stalls are virtually unrecoverable. Fortunately, they are easily avoided as long as published limitations are observed. On those airplanes susceptible to deep stalls (not all swept and/or tapered wing airplanes are), sophisticated stall warning systems such as stick shakers and stick pushers are standard equipment. A stick pusher, as its name implies, acts to automatically reduce the airplane’s angle of attack before the airplane reaches a fully stalled condition. Unless the Airplane Flight Manual procedures stipulate otherwise, a fully stalled condition in a jet airplane is to be avoided. Pilots undergoing training in jet airplanes are taught to recover at the first sign of an impending stall. Normally, this is indicated by aural stall warning devices and/or activation of the airplane’s stick shaker. Stick shakers normally activate around 107 percent of the actual stall speed. At such slow speeds, very high sink rates can develop if the airplane’s pitch attitude is decreased below the horizon, as is normal recovery procedure in most piston powered straight wing, light airplanes. Therefore, at the lower altitudes where plenty of engine thrust is available, the recovery technique in many sweptwing jets involves applying full available power, rolling the wings level, and holding a slightly positive pitch attitude. The amount of pitch attitude should be sufficient enough to maintain altitude or begin a slight climb. At high altitudes, where there may be little excess thrust available to effect a recovery using power alone, it may be necessary to lower the nose below the horizon in order to accelerate away from an impending stall. This procedure may require several thousand feet or more of altitude loss to effect a recovery. Stall recovery techniques may vary considerably from airplane to airplane. The stall recovery procedures for a particular make and model airplane, as recommended by the manufacturer, are contained in the FAA-approved Airplane Flight Manual for that airplane. DRAG DEVICES To the pilot transitioning into jet airplanes, going faster is seldom a problem. It is getting the airplane to slow down that seems to cause the most difficulty. This is because of the extremely clean aerodynamic design and fast momentum of the jet airplane, and also because the jet lacks the propeller drag effects that the pilot has been accustomed to. Additionally, even with the power reduced to flight idle, the jet engine still produces thrust, and deceleration of the jet airplane is a slow process. Jet airplanes have a glide performance that is double that of piston powered airplanes, and jet pilots often cannot comply with an air traffic control request to go down and slow down at the same time. Therefore, jet airplanes are equipped with drag devices such as spoilers and speed brakes. The primary purpose of spoilers is to spoil lift. The most common type of spoiler consists of one or more rectangular plates that lie flush with the upper surface of each wing. They are installed approximately parallel to the lateral axis of the airplane and are hinged along the leading edges. When deployed, spoilers deflect up against the relative wind, which interferes with the flow of air about the wing. [Figure 15-18] This both spoils lift and increases drag. Spoilers are usually installed forward of the flaps but not in front of the ailerons so as not to interfere with roll control. Initial Stall Deep Stall Pre-Stall Relative Wind Relative Wind Relative Wind Pitch Attitude Flightpath Angle to the Horizontal Angle of Attack Figure 15-17. Deep stall progression. Figure 15-18. Spoilers. Ch 15.qxd 5/7/04 10:22 AM Page 15-13 15-14 Deploying spoilers results in a substantial sink rate with little decay in airspeed. Some airplanes will exhibit a noseup pitch tendency when the spoilers are deployed, which the pilot must anticipate. When spoilers are deployed on landing, most of the wing’s lift is destroyed. This action transfers the airplane’s weight to the landing gear so that the wheel brakes are more effective. Another beneficial effect of deploying spoilers on landing is that they create considerable drag, adding to the overall aerodynamic braking. The real value of spoilers on landing, however, is creating the best circumstances for using wheel brakes. The primary purpose of speed brakes is to produce drag. Speed brakes are found in many sizes, shapes, and locations on different airplanes, but they all have the same purpose—to assist in rapid deceleration. The speed brake consists of a hydraulically operated board that when deployed extends into the airstream. Deploying speed brakes results in a rapid decrease in airspeed. Typically, speed brakes can be deployed at any time during flight in order to help control airspeed, but they are most often used only when a rapid deceleration must be accomplished to slow down to landing gear and flap speeds. There is usually a certain amount of noise and buffeting associated with the use of speed brakes, along with an obvious penalty in fuel consumption. Procedures for the use of spoilers and/or speed brakes in various situations are contained in the FAA-approved Airplane Flight Manual for the particular airplane. THRUST REVERSERS Jet airplanes have high kinetic energy during the landing roll because of weight and speed. This energy is difficult to dissipate because a jet airplane has low drag with the nosewheel on the ground and the engines continue to produce forward thrust with the power levers at idle. While wheel brakes normally can cope, there is an obvious need for another speed retarding method. This need is satisfied by the drag provided by reverse thrust. A thrust reverser is a device fitted in the engine exhaust system which effectively reverses the flow of the exhaust gases. The flow does not reverse through 180°; however, the final path of the exhaust gases is about 45° from straight ahead. This, together with the losses in the reverse flow paths, results in a net efficiency of about 50 percent. It will produce even less if the engine r.p.m. is less than maximum in reverse. Normally, a jet engine will have one of two types of thrust reversers, either a target reverser or a cascade reverser. [Figure 15-19] Target reversers are simple clamshell doors that swivel from the stowed position at the engine tailpipe to block all of the outflow and redirect some component of the thrust forward. Cascade reversers are more complex. They are normally found on turbofan engines and are often designed to reverse only the fan air portion. Blocking doors in the shroud obstructs forward fan thrust and redirects it through cascade vanes for some reverse component. Cascades are generally less effective than target reversers, particularly those that reverse only fan air, because they do not affect the engine core, which will continue to produce forward thrust. On most installations, reverse thrust is obtained with the thrust lever at idle, by pulling up the reverse lever to a detent. Doing so positions the reversing mechanisms for operation but leaves the engine at idle r.p.m. Further upward and backward movement of the reverse lever increases engine power. Reverse is cancelled by closing the reverse lever to the idle reverse position, then dropping it fully back to the forward idle position. This last movement operates the reverser back to the forward thrust position. Reverse thrust is much more effective at high airplane speed than at low airplane speeds, for two reasons: first, the net amount of reverse thrust increases with speed; second, the power produced is higher at higher speeds because of the increased rate of doing work. In other words, the kinetic energy of the airplane is being destroyed at a higher rate at the higher speeds. To get maximum efficiency from reverse thrust, therefore, it should be used as soon as is prudent after touchdown. When considering the proper time to apply reverse thrust after touchdown, the pilot should remember that TARGET OR CLAMSHELL REVERSER CASCADE REVERSER Figure 15-19. Thrust reversers. Ch 15.qxd 5/7/04 10:22 AM Page 15-14 15-15 some airplanes tend to pitch noseup when reverse is selected on landing and this effect, particularly when combined with the noseup pitch effect from the spoilers, can cause the airplane to leave the ground again momentarily. On these types, the airplane must be firmly on the ground with the nosewheel down, before reverse is selected. Other types of airplanes have no change in pitch, and reverse idle may be selected after the main gear is down and before the nosewheel is down. Specific procedures for reverse thrust operation for a particular airplane/engine combination are contained in the FAA-approved Airplane Flight Manual for that airplane. There is a significant difference between reverse pitch on a propeller and reverse thrust on a jet. Idle reverse on a propeller produces about 60 percent of the reverse thrust available at full power reverse and is therefore very effective at this setting when full reverse is not needed. On a jet engine, however, selecting idle reverse produces very little actual reverse thrust. In a jet airplane, the pilot must not only select reverse as soon as reasonable, but then must open up to full power reverse as soon as possible. Within Airplane Flight Manual limitations, full power reverse should be held until the pilot is certain the landing roll will be contained within the distance available. Inadvertent deployment of thrust reversers is a very serious emergency situation. Therefore, thrust reverser systems are designed with this prospect in mind. The systems normally contain several lock systems: one to keep reversers from operating in the air, another to prevent operation with the thrust levers out of the idle detent, and/or an “auto-stow” circuit to command reverser stowage any time unwanted motion is detected. It is essential that pilots understand not only the normal procedures and limitations of thrust reverser use, but also the procedures for coping with uncommanded reverse. Those emergencies demand immediate and accurate response. PILOT SENSATIONS IN JET FLYING There are usually three general sensations that the pilot transitioning into jets will immediately become aware of. These are: inertial response differences, increased control sensitivity, and a much increased tempo of flight. The varying of power settings from flight idle to full takeoff power has a much slower effect on the change of airspeed in the jet airplane. This is commonly called lead and lag, and is as much a result of the extremely clean aerodynamic design of the airplane as it is the slower response of the engine. The lack of propeller effect is also responsible for the lower drag increment at the reduced power settings and results in other changes that the pilot will have to become accustomed to. These include the lack of effective slipstream over the lifting surfaces and control surfaces, and lack of propeller torque effect. The aft mounted engines will cause a different reaction to power application and may result in a slightly nosedown pitching tendency with the application of power. On the other hand, power reduction will not cause the nose of the airplane to drop to the same extent the pilot is used to in a propeller airplane. Although neither of these characteristics are radical enough to cause transitioning pilots much of a problem, they must be compensated for. Power settings required to attain a given performance are almost impossible to memorize in the jets, and the pilot who feels the necessity for having an array of power settings for all occasions will initially feel at a loss. The only way to answer the question of “how much power is needed?” is by saying, “whatever is required to get the job done.” The primary reason that power settings vary so much is because of the great changes in weight as fuel is consumed during the flight. Therefore, the pilot will have to learn to use power as needed to achieve the desired performance. In time the pilot will find that the only reference to power instruments will be that required to keep from exceeding limits of maximum power settings or to synchronize r.p.m. Proper power management is one of the initial problem areas encountered by the pilot transitioning into jet airplanes. Although smooth power applications are still the rule, the pilot will be aware that a greater physical movement of the power levers is required as compared to throttle movement in the piston engines. The pilot will also have to learn to anticipate and lead the power changes more than in the past and must keep in mind that the last 30 percent of engine r.p.m. represents the majority of the engine thrust, and below that the application of power has very little effect. In slowing the airplane, power reduction must be made sooner because there is no longer any propeller drag and the pilot should anticipate the need for drag devices. Control sensitivity will differ between various airplanes, but in all cases, the pilot will find that they are more sensitive to any change in control displacement, particularly pitch control, than are the conventional propeller airplanes. Because of the higher speeds flown, the control surfaces are more effective and a variation of just a few degrees in pitch attitude in a jet can result in over twice the rate of altitude change that would be experienced in a slower airplane. The sensitive pitch control in jet airplanes is one of the first flight differences that the pilot will notice. Invariably the pilot will have a tendency to over-control pitch Ch 15.qxd 5/7/04 10:22 AM Page 15-15 15-16 during initial training flights. The importance of accurate and smooth control cannot be overemphasized, however, and it is one of the first techniques the transitioning pilot must master. The pilot of a sweptwing jet airplane will soon become adjusted to the fact that it is necessary and normal to fly at higher angles of attack. It is not unusual to have about 5° of noseup pitch on an approach to a landing. During an approach to a stall at constant altitude, the noseup angle may be as high as 15° to 20°. The higher deck angles (pitch angle relative to the ground) on takeoff, which may be as high as 15°, will also take some getting used to, although this is not the actual angle of attack relative to the airflow over the wing. The greater variation of pitch attitudes flown in a jet airplane are a result of the greater thrust available and the flight characteristics of the low aspect ratio and sweptwing. Flight at the higher pitch attitudes requires a greater reliance on the flight instruments for airplane control since there is not much in the way of a useful horizon or other outside reference to be seen. Because of the high rates of climb and descent, high airspeeds, high altitudes and variety of attitudes flown, the jet airplane can only be precisely flown by applying proficient instrument flight techniques. Proficiency in attitude instrument flying, therefore, is essential to successful transition to jet airplane flying. Most jet airplanes are equipped with a thumb operated pitch trim button on the control wheel which the pilot must become familiar with as soon as possible. The jet airplane will differ regarding pitch tendencies with the lowering of flaps, landing gear, and drag devices. With experience, the jet airplane pilot will learn to anticipate the amount of pitch change required for a particular operation. The usual method of operating the trim button is to apply several small, intermittent applications of trim in the direction desired rather than holding the trim button for longer periods of time which can lead to over-controlling. JET AIRPLANE TAKEOFF AND CLIMB All FAAcertificated jet airplanes are certificated under Title 14 of the Code of Federal Regulations (14 CFR) part 25, which contains the airworthiness standards for transport category airplanes. The FAA certificated jet airplane is a highly sophisticated machine with proven levels of performance and guaranteed safety margins. The jet airplane’s performance and safety margins can only be realized, however, if the airplane is operated in strict compliance with the procedures and limitations contained in the FAA-approved Airplane Flight Manual for the particular airplane. The following information is generic in nature and, since most civilian jet airplanes require a minimum flight crew of two pilots, assumes a two pilot crew. If any of the following information conflicts with FAAapproved Airplane Flight Manual procedures for a particular airplane, the Airplane Flight Manual procedures take precedence. Also, if any of the following procedures differ from the FAA-approved procedures developed for use by a specific air operator and/or for use in an FAA-approved training center or pilot school curriculum, the FAA-approved procedures for that operator and/or training center/pilot school take precedence. V-SPEEDS The following are speeds that will affect the jet airplane’s takeoff performance. The jet airplane pilot must be thoroughly familiar with each of these speeds and how they are used in the planning of the takeoff. • VS—Stall speed. • V1—Critical engine failure speed or decision speed. Engine failure below this speed should result in an aborted takeoff; above this speed the takeoff run should be continued. • VR—Speed at which the rotation of the airplane is initiated to takeoff attitude. This speed cannot be less than V1 or less than 1.05 x VMCA (minimum control speed in the air). On a single-engine takeoff, it must also allow for the acceleration to V2 at the 35-foot height at the end of the runway. • VLO—The speed at which the airplane first becomes airborne. This is an engineering term used when the airplane is certificated and must meet certain requirements. If it is not listed in the Airplane Flight Manual, it is within requirements and does not have to be taken into consideration by the pilot. • V2—The takeoff safety speed which must be attained at the 35-foot height at the end of the required runway distance. This is essentially the best single-engine angle of climb speed for the airplane and should be held until clearing obstacles after takeoff, or at least 400 feet above the ground. PRE-TAKEOFF PROCEDURES Takeoff data, including V1/VR and V2 speeds, takeoff power settings, and required field length should be computed prior to each takeoff and recorded on a takeoff data card. These data will be based on airplane weight, runway length available, runway gradient, field temperature, field barometric pressure, wind, icing conditions, and runway condition. Both pilots should separately compute the takeoff data and cross-check in the cockpit with the takeoff data card. Ch 15.qxd 5/7/04 10:22 AM Page 15-16 15-17 A captain’s briefing is an essential part of cockpit resource management (CRM) procedures and should be accomplished just prior to takeoff. [Figure 15-20] The captain’s briefing is an opportunity to review crew coordination procedures for takeoff, which is always the most critical portion of a flight. The takeoff and climb-out should be accomplished in accordance with a standard takeoff and departure profile developed for the particular make and model airplane. [Figure 15-21] TAKEOFF ROLL The entire runway length should be available for takeoff, especially if the pre-calculated takeoff performance shows the airplane to be limited by runway length or obstacles. After taxing into position at the end of the runway, the airplane should be aligned in the center of the runway allowing equal distance on either side. The brakes should be held while the thrust levers are brought to a power setting beyond the bleed valve range (normally the vertical position) and the engines allowed to stabilized. The engine instruments should be checked for proper operation before the brakes are released or the power increased further. This procedure assures symmetrical thrust during the takeoff roll and aids in preventing overshooting the desired takeoff thrust setting. The brakes should then be released and, during the start of the takeoff roll, the thrust levers smoothly advanced to the pre-computed takeoff power setting. All final takeoff thrust adjustments should be made prior to reaching 60 knots. The final engine power adjustments are normally made by the pilot not flying. Once the thrust levers are set for takeoff power, they should not be readjusted after 60 knots. Retarding a thrust lever would only be necessary in case an engine exceeds any limitation such as ITT, fan, or turbine r.p.m. CAPTAIN'S BRIEFING I will advance the thrust levers. Follow me through on the thrust levers. Monitor all instruments and warning lights on the takeoff roll and call out any discrepancies or malfunctions observed prior to V1, and I will abort the takeoff. Stand by to arm thrust reversers on my command. Give me a visual and oral signal for the following: • 80 knots, and I will disengage nosewheel steering. • V1, and I will move my hand from thrust to yoke. • VR, and I will rotate. In the event of engine failure at or after V1, I will continue the takeoff roll to VR, rotate and establish V2 climb speed. I will identify the inoperative engine, and we will both verify. I will accomplish the shutdown, or have you do it on my command. I will expect you to stand by on the appropriate emergency checklist. I will give you a visual and oral signal for gear retraction and for power settings after the takeoff. Our VFR emergency procedure is to............................. Our IFR emergency procedure is to.............................. Figure 15-20. Sample captain’s briefing. • Set Takeoff Thrust Prior to 60 Knots • 70 Knots Check • V1/VR • Rotate Smoothly to 10° Nose Up • Positive Rate of Climb • Gear Up • V2 + 10 Knots Minimum Altitude Selected to Flap Retraction (400 Ft. FAA Minimum) (or Obstacle Clearance Altitude) Close-In Turn Maintain: • Flaps T.O. & Appr. • V2 + 20 Knots Minimum • Maximum Bank 30° Straight Climbout: • V2 + 10 Knots • Retract Flaps • Set Climb Thrust • Complete After-Takeoff Climb Checklist Rollout: • V2 + 20 Minimum • Set Climb Thrust • Accelerate • Retract Flaps • Complete After-Takeoff Climb Checklist NORMAL TAKEOFF Figure 15-21.Takeoff and departure profile. Ch 15.qxd 5/7/04 10:22 AM Page 15-17 15-18 If sufficient runway length is available, a “rolling” takeoff may be made without stopping at the end of the runway. Using this procedure, as the airplane rolls onto the runway, the thrust levers should be smoothly advanced to the vertical position and the engines allowed to stabilize, and then proceed as in the static takeoff outlined above. Rolling takeoffs can also be made from the end of the runway by advancing the thrust levers from idle as the brakes are released. During the takeoff roll, the pilot flying should concentrate on directional control of the airplane. This is made somewhat easier because there is no torqueproduced yawing in a jet as there is in a propeller driven airplane. The airplane must be maintained exactly on centerline with the wings level. This will automatically aid the pilot when contending with an engine failure. If a crosswind exists, the wings should be kept level by displacing the control wheel into the crosswind. During the takeoff roll, the primary responsibility of the pilot not flying is to closely monitor the aircraft systems and to call out the proper V speeds as directed in the captain’s briefing. Slight forward pressure should be held on the control column to keep the nosewheel rolling firmly on the runway. If nosewheel steering is being utilized, the pilot flying should monitor the nosewheel steering to about 80 knots (or VMCG for the particular airplane) while the pilot not flying applies the forward pressure. After reaching VMCG, the pilot flying should bring his/her left hand up to the control wheel. The pilot’s other hand should be on the thrust levers until at least V1 speed is attained. Although the pilot not flying maintains a check on the engine instruments throughout the takeoff roll, the pilot flying (pilot in command) makes the decision to continue or reject a takeoff for any reason. A decision to reject a takeoff will require immediate retarding of thrust levers. The pilot not flying should call out V1. After passing V1 speed on the takeoff roll, it is no longer mandatory for the pilot flying to keep a hand on the thrust levers. The point for abort has passed, and both hands may be placed on the control wheel. As the airspeed approaches VR, the control column should be moved to a neutral position. As the pre-computed VR speed is attained, the pilot not flying should make the appropriate callout and the pilot flying should smoothly rotate the airplane to the appropriate takeoff pitch attitude. ROTATION AND LIFT-OFF Rotation and lift-off in a jet airplane should be considered a maneuver unto itself. It requires planning, precision, and a fine control touch. The objective is to initiate the rotation to takeoff pitch attitude exactly at VR so that the airplane will accelerate through VLOF and attain V2 speed at 35 feet at the end of the runway. Rotation to the proper takeoff attitude too soon may extend the takeoff roll or cause an early lift-off, which will result in a lower rate of climb, and the predicted flightpath will not be followed. A late rotation, on the other hand, will result in a longer takeoff roll, exceeding V2 speed, and a takeoff and climb path below the predicted path. Each airplane has its own specific takeoff pitch attitude which remains constant regardless of weight. The takeoff pitch attitude in a jet airplane is normally between 10° and 15° nose up. The rotation to takeoff pitch attitude should be made smoothly but deliberately, and at a constant rate. Depending on the particular airplane, the pilot should plan on a rate of pitch attitude increase of approximately 2.5° to 3° per second. In training it is common for the pilot to overshoot VR and then overshoot V2 because the pilot not flying will call for rotation at, or just past VR. The reaction of the pilot flying is to visually verify VR and then rotate. The airplane then leaves the ground at or above V2. The excess airspeed may be of little concern on a normal takeoff, but a delayed rotation can be critical when runway length or obstacle clearance is limited. It should be remembered that on some airplanes, the all-engine takeoff can be more limiting than the engine out takeoff in terms of obstacle clearance in the initial part of the climb-out. This is because of the rapidly increasing airspeed causing the achieved flightpath to fall below the engine out scheduled flightpath unless care is taken to fly the correct speeds. The transitioning pilot should remember that rotation at the right speed and rate to the right attitude will get the airplane off the ground at the right speed and within the right distance. INITIAL CLIMB Once the proper pitch attitude is attained, it must be maintained. The initial climb after lift-off is done at this constant pitch attitude. Takeoff power is maintained and the airspeed allowed to accelerate. Landing gear retraction should be accomplished after a positive rate of climb has been established and confirmed. Remember that in some airplanes gear retraction may temporarily increase the airplane drag while landing gear doors open. Premature gear retraction may cause the airplane to settle back towards the runway surface. Remember also that because of ground effect, the vertical speed indicator and the altimeter may not show a positive climb until the airplane is 35 to 50 feet above the runway. The climb pitch attitude should continue to be held and the airplane allowed to accelerate to flap retraction speed. However, the flaps should not be retracted until Ch 15.qxd 5/7/04 10:22 AM Page 15-18 15-19 obstruction clearance altitude or 400 feet AGL has been passed. Ground effect and landing gear drag reduction results in rapid acceleration during this phase of the takeoff and climb. Airspeed, altitude, climb rate, attitude, and heading must be monitored carefully. When the airplane settles down to a steady climb, longitudinal stick forces can be trimmed out. If a turn must be made during this phase of flight, no more than 15° to 20° of bank should be used. Because of spiral instability, and because at this point an accurate trim state on rudder and ailerons has not yet been achieved, the bank angle should be carefully monitored throughout the turn. If a power reduction must be made, pitch attitude should be reduced simultaneously and the airplane monitored carefully so as to preclude entry into an inadvertent descent. When the airplane has attained a steady climb at the appropriate en route climb speed, it can be trimmed about all axes and the autopilot engaged. JET AIRPLANE APPROACH AND LANDING LANDING REQUIREMENTS The FAA landing field length requirements for jet airplanes are specified in 14 CFR part 25. It defines the minimum field length (and therefore minimum margins) that can be scheduled. The regulation describes the landing profile as the distance required from a point 50 feet above the runway threshold, through the flare to touchdown, and then stopping using the maximum stopping capability on a dry runway surface. The actual demonstrated distance is increased by 67 percent and published in the FAAapproved Airplane Flight Manual as the FAR dry runway landing distance. [Figure 15-22] For wet runways, the FAR dry runway distance is increased by an additional 15 percent. Thus the minimum dry runway field length will be 1.67 times the actual minimum air and ground distance needed and the wet runway minimum landing field length will be 1.92 times the minimum dry air and ground distance needed. Certified landing field length requirements are computed for the stop made with speed brakes deployed and maximum wheel braking. Reverse thrust is not used in establishing the certified FAR landing distances. However, reversers should definitely be used in service. LANDING SPEEDS As in the takeoff planning, there are certain speeds that must be taken into consideration during any landing in a jet airplane. The speeds are as follows. • VSO—Stall speed in the landing configuration. • VREF—1.3 times the stall speed in the landing configuration. • Approach climb—The speed which guarantees adequate performance in a go-around situation with an inoperative engine. The airplane’s weight must be limited so that a twin-engine airplane will have a 2.1 percent climb gradient capability. (The approach climb gradient requirements for 3 and 4 engine airplanes are 2.4 percent and 2.7 percent respectively.) These criteria are based on an airplane configured with approach flaps, landing gear up, and takeoff thrust available from the operative engine(s). • Landing climb—The speed which guarantees adequate performance in arresting the descent and making a go-around from the final stages of landing with the airplane in the full landing configuration and maximum takeoff power available on all engines. The appropriate speeds should be pre-computed prior to every landing, and posted where they are visible to both pilots. The VREF speed, or threshold speed, is used VREF = 1.3 VS 50 Ft. TD Actual Distance 60% 40% FAR (Dry) Runway Field Length Required 1.67 x Actual Distance FAR (Wet) Runway Field Length Required 1.15 x FAR (Dry) or 1.92 x Actual Distance 15% Figure 15-22. FAR landing field length required. Ch 15.qxd 5/7/04 10:22 AM Page 15-19 15-20 as a reference speed throughout the traffic pattern. For example: Downwind leg—VREF plus 20 knots. Base leg—VREF plus 10 knots. Final approach—VREF plus 5 knots. 50 feet over threshold—VREF. The approach and landing sequence in a jet airplane should be accomplished in accordance with an approach and landing profile developed for the particular airplane. [Figure 15-23] SIGNIFICANT DIFFERENCES Asafe approach in any type of airplane culminates in a particular position, speed, and height over the runway threshold. That final flight condition is the target window at which the entire approach aims. Propeller powered airplanes are able to approach that target from wider angles, greater speed differentials, and a larger variety of glidepath angles. Jet airplanes are not as responsive to power and course corrections, so the final approach must be more stable, more deliberate, more constant, in order to reach the window accurately. The transitioning pilot must understand that, in spite of their impressive performance capabilities, there are six ways in which a jet airplane is worse than a piston engine airplane in making an approach and in correcting errors on the approach. • The absence of the propeller slipstream in producing immediate extra lift at constant airspeed. There is no such thing as salvaging a misjudged glidepath with a sudden burst of immediately available power. Added lift can only be achieved by accelerating the airframe. Not only must the pilot wait for added power but even when the engines do respond, added lift will only be available when the airframe has responded with speed. • The absence of the propeller slipstream in significantly lowering the power-on stall speed. There is virtually no difference between poweron and power-off stall speed. It is not possible in a jet airplane to jam the thrust levers forward to avoid a stall. • Poor acceleration response in a jet engine from low r.p.m. This characteristic requires that the approach be flown in a high drag/high power 1. Reset Bug to VREF 2. Review Airport Characteristics 3. Complete Descent and Begin Before Landing Checklist Abeam Runway Midpoint • Flaps T/O Approach • VREF + 20 Minimum 1500' Above Field Elevation • Complete Before Landing Checklist • Maximum Bank 30° • Clear Final Approach Rollout • Reduce Speed to VREF • Altitude Callouts • Stabilized in Slot DO NOT MAKE FLAT APPROACH Touchdown • Extend Speed Brake • Apply Brakes • Thrust reverser or Drag Chute as Required Fly VREF Abeam Touchdown Point • Gear Down Turning Base • Flaps Land • Initially Set Fuel Flow to 400 Lb./Engine • Start Descent • VREF + 10 Minimum on Base APPROACH PREPARATIONS Figure 15-23.Typical approach and landing profile. Ch 15.qxd 5/7/04 10:22 AM Page 15-20 15-21 configuration so that sufficient power will be available quickly if needed. • The increased momentum of the jet airplane making sudden changes in the flightpath impossible. Jet airplanes are consistently heavier than comparable sized propeller airplanes. The jet airplane, therefore, will require more indicated airspeed during the final approach due to a wing design that is optimized for higher speeds. These two factors combine to produce higher momentum for the jet airplane. Since force is required to overcome momentum for speed changes or course corrections, the jet will be far less responsive than the propeller airplane and require careful planning and stable conditions throughout the approach. • The lack of good speed stability being an inducement to a low speed condition. The drag curve for many jet airplanes is much flatter than for propeller airplanes, so speed changes do not produce nearly as much drag change. Further, jet thrust remains nearly constant with small speed changes. The result is far less speed stability. When the speed does increase or decrease, there is little tendency for the jet airplane to re-acquire the original speed. The pilot, therefore, must remain alert to the necessity of making speed adjustments, and then make them aggressively in order to remain on speed. • Drag increasing faster than lift producing a high sink rate at low speeds. Jet airplane wings typically have a large increase in drag in the approach configuration. When a sink rate does develop, the only immediate remedy is to increase pitch attitude (angle of attack). Because drag increases faster than lift, that pitch change will rapidly contribute to an even greater sink rate unless a significant amount of power is aggressively applied. These flying characteristics of jet airplanes make a stabilized approach an absolute necessity. THE STABILIZED APPROACH The performance charts and the limitations contained in the FAA-approved Airplane Flight Manual are predicated on momentum values that result from programmed speeds and weights. Runway length limitations assume an exact 50-foot threshold height at an exact speed of 1.3 times VSO. That “window” is critical and is a prime reason for the stabilized approach. Performance figures also assume that once through the target threshold window, the airplane will touch down in a target touchdown zone approximately 1,000 feet down the runway, after which maximum stopping capability will be used. There are five basic elements to the stabilized approach. • The airplane should be in the landing configuration early in the approach. The landing gear should be down, landing flaps selected, trim set, and fuel balanced. Ensuring that these tasks are completed will help keep the number of variables to a minimum during the final approach. • The airplane should be on profile before descending below 1,000 feet. Configuration, trim, speed, and glidepath should be at or near the optimum parameters early in the approach to avoid distractions and conflicts as the airplane nears the threshold window. An optimum glidepath angle of 2.5° to 3° should be established and maintained. • Indicated airspeed should be within 10 knots of the target airspeed. There are strong relationships between trim, speed, and power in most jet airplanes and it is important to stabilize the speed in order to minimize those other variables. • The optimum descent rate should be 500 to 700 feet per minute. The descent rate should not be allowed to exceed 1,000 feet per minute at any time during the approach. • The engine speed should be at an r.p.m. that allows best response when and if a rapid power increase is needed. Every approach should be evaluated at 500 feet. In a typical jet airplane, this is approximately 1 minute from touchdown. If the approach is not stabilized at that height, a go-around should be initiated. (See figure 15-24 on the next page.) APPROACH SPEED On final approach, the airspeed is controlled with power. Any speed diversion from VREF on final approach must be detected immediately and corrected. With experience the pilot will be able to detect the very first tendency of an increasing or decreasing airspeed trend, which normally can be corrected with a small adjustment in thrust. The pilot must be attentive to poor speed stability leading to a low speed condition with its attendant risk of high drag increasing the sink rate. Remember that with an increasing sink rate an apparently normal pitch attitude is no guarantee of a normal angle of attack value. If an increasing sink rate is detected, it must be countered by increasing the angle Ch 15.qxd 5/7/04 10:22 AM Page 15-21 15-22 of attack and simultaneously increasing thrust to counter the extra drag. The degree of correction required will depend on how much the sink rate needs to be reduced. For small amounts, smooth and gentle, almost anticipatory corrections will be sufficient. For large sink rates, drastic corrective measures may be required that, even if successful, would destabilize the approach. A common error in the performance of approaches in jet airplanes is excess approach speed. Excess approach speed carried through the threshold window and onto the runway will increase the minimum stopping distance required by 20 – 30 feet per knot of excess speed for a dry runway and 40 – 50 feet for a wet runway. Worse yet, the excess speed will increase the chances of an extended flare, which will increase the distance to touchdown by approximately 250 feet for each excess knot in speed. Proper speed control on final approach is of primary importance. The pilot must anticipate the need for speed adjustment so that only small adjustments are required. It is essential that the airplane arrive at the approach threshold window exactly on speed. GLIDEPATH CONTROL On final approach, at a constant airspeed, the glidepath angle and rate of descent is controlled with pitch attitude and elevator. The optimum glidepath angle is 2.5° to 3° whether or not an electronic glidepath reference is being used. On visual approaches, pilots may have a tendency to make flat approaches. A flat approach, however, will increase landing distance and should be avoided. For example, an approach angle of 2° instead of a recommended 3° will add 500 feet to landing distance. A more common error is excessive height over the threshold. This could be the result of an unstable approach, or a stable but high approach. It also may occur during an instrument approach where the missed approach point is close to or at the runway threshold. Regardless of the cause, excessive height over the threshold will most likely result in a touchdown beyond the normal aiming point. An extra 50 feet of height over the threshold will add approximately 1,000 feet to the landing distance. It is essential that the airplane arrive at the approach threshold window exactly on altitude (50 feet above the runway). THE FLARE The flare reduces the approach rate of descent to a more acceptable rate for touchdown. Unlike light airplanes, a jet airplane should be flown onto the runway rather than “held off” the surface as speed dissipates. A jet airplane is aerodynamically clean even in the landing configuration, and its engines still produce residual thrust at idle r.p.m. Holding it off during the flare in a attempt to make a smooth landing will greatly increase landing distance. A firm landing is normal and desirable. A firm landing does not mean a hard landing, but rather a deliberate or positive landing. For most airports, the airplane will pass over the end of the runway with the landing gear 30 – 45 feet above the surface, depending on the landing flap setting and the location of the touchdown zone. It will take 5 – 7 seconds from the time the airplane passes the end of Figure 15-24. Stabilized approach. Stop Rollout Touchdown 1,000' Threshold Window 50' VREF 500' Window Check for Stabilized Approach Stabilized Approach on Course on Speed 2.5° - 3° Glidepath 500 - 700 FPM Descent 1,000' Window Flare Ch 15.qxd 5/7/04 10:22 AM Page 15-22 15-23 the runway until touchdown. The flare is initiated by increasing the pitch attitude just enough to reduce the sink rate to 100 – 200 feet per minute when the landing gear is approximately 15 feet above the runway surface. In most jet airplanes, this will require a pitch attitude increase of only 1° to 3°. The thrust is smoothly reduced to idle as the flare progresses. The normal speed bleed off during the time between passing the end of the runway and touchdown is 5 knots. Most of the decrease occurs during the flare when thrust is reduced. If the flare is extended (held off) while an additional speed is bled off, hundreds or even thousands of feet of runway may be used up. [Figure 15-25] The extended flare will also result in additional pitch attitude which may lead to a tail strike. It is, therefore, essential to fly the airplane onto the runway at the target touchdown point, even if the speed is excessive. A deliberate touchdown should be planned and practiced on every flight. A positive touchdown will help prevent an extended flare. Pilots must learn the flare characteristics of each model of airplane they fly. The visual reference cues observed from each cockpit are different because window geometry and visibility are different. The geometric relationship between the pilot’s eye and the landing gear will be different for each make and model. It is essential that the flare maneuver be initiated at the proper height—not too high and not too low. Beginning the flare too high or reducing the thrust too early may result in the airplane floating beyond the target touchdown point or may include a rapid pitch up as the pilot attempts to prevent a high sink rate touchdown. This can lead to a tail strike. The flare that is initiated too late may result in a hard touchdown. Proper thrust management through the flare is also important. In many jet airplanes, the engines produce a noticeable effect on pitch trim when the thrust setting is changed. Arapid change in the thrust setting requires a quick elevator response. If the thrust levers are moved to idle too quickly during the flare, the pilot must make rapid changes in pitch control. If the thrust levers are moved more slowly, the elevator input can be more easily coordinated. Touchdown On Target Extended Flare 10 Knots Deceleration on Ground (Maximum Braking) 10 Knots Deceleration in Flare 200 Ft. (Dry Runway) 500 Ft. (Wet Runway) 2,000 Ft. (Air) Figure 15-25. Extended flare. Ch 15.qxd 5/7/04 10:22 AM Page 15-23 15-24 TOUCHDOWN AND ROLLOUT A proper approach and flare positions the airplane to touch down in the touchdown target zone, which is usually about 1,000 feet beyond the runway threshold. Once the main wheels have contacted the runway, the pilot must maintain directional control and initiate the stopping process. The stop must be made on the runway that remains in front of the airplane. The runway distance available to stop is longest if the touchdown was on target. The energy to be dissipated is least if there is no excess speed. The stop that begins with a touchdown that is on the numbers will be the easiest stop to make for any set of conditions. At the point of touchdown, the airplane represents a very large mass that is moving at a relatively high speed. The large total energy must be dissipated by the brakes, the aerodynamic drag, and the thrust reversers. The nosewheel should be flown onto the ground immediately after touchdown because a jet airplane decelerates poorly when held in a nose-high attitude. Placing the nosewheel tire(s) on the ground will assist in maintaining directional control. Also, lowering the nose gear decreases the wing angle of attack, decreasing the lift, placing more load onto the tires, thereby increasing tire-to-ground friction. Landing distance charts for jet airplanes assume that the nosewheel is lowered onto the runway within 4 seconds of touchdown. There are only three forces available for stopping the airplane. They are wheel braking, reverse thrust, and aerodynamic braking. Of the three, the brakes are most effective and therefore the most important stopping force for most landings. When the runway is very slippery, reverse thrust and drag may be the dominant forces. Both reverse thrust and aerodynamic drag are most effective at high speeds. Neither is affected by runway surface condition. Brakes, on the other hand, are most effective at low speed. The landing rollout distance will depend on the touchdown speed and what forces are applied and when they are applied. The pilot controls the what and when factors, but the maximum braking force may be limited by tire-to-ground friction. The pilot should begin braking as soon after touchdown and wheel spin-up as possible, and to smoothly continue the braking until stopped or a safe taxi speed is reached. However, caution should be used if the airplane is not equipped with a functioning anti-skid system. In such a case, heavy braking can cause the wheels to lock and the tires to skid. Both directional control and braking utilize tire ground friction. They share the maximum friction force the tires can provide. Increasing either will subtract from the other. Understanding tire ground friction, how runway contamination affects it, and how to use the friction available to maximum advantage is important to a jet pilot. Spoilers should be deployed immediately after touchdown because they are most effective at high speed. Timely deployment of spoilers will increase drag by 50 to 60 percent, but more importantly, they spoil much of the lift the wing is creating, thereby causing more of the weight of the airplane to be loaded onto the wheels. The spoilers increase wheel loading by as much as 200 percent in the landing flap configuration. This increases the tire ground friction force making the maximum tire braking and cornering forces available. Like spoilers, thrust reversers are most effective at high speeds and should be deployed quickly after touchdown. However, the pilot should not command significant reverse thrust until the nosewheel is on the ground. Otherwise, the reversers might deploy asymmetrically resulting in an uncontrollable yaw towards the side on which the most reverse thrust is being developed, in which case the pilot will need whatever nosewheel steering is available to maintain directional control. Ch 15.qxd 5/7/04 10:22 AM Page 15-24

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16-1 EMERGENCY SITUATIONS This chapter contains information on dealing with non-normal and emergency situations that may occur in flight. The key to successful management of an emergency situation, and/or preventing a non-normal situation from progressing into a true emergency, is a thorough familiarity with, and adherence to, the procedures developed by the airplane manufacturer and contained in the FAA-approved Airplane Flight Manual and/or Pilot’s Operating Handbook (AFM/POH). The following guidelines are generic and are not meant to replace the airplane manufacturer’s recommended procedures. Rather, they are meant to enhance the pilot’s general knowledge in the area of non-normal and emergency operations. If any of the guidance in this chapter conflicts in any way with the manufacturer’s recommended procedures for a particular make and model airplane, the manufacturer’s recommended procedures take precedence. EMERGENCY LANDINGS This section contains information on emergency landing techniques in small fixed-wing airplanes. The guidelines that are presented apply to the more adverse terrain conditions for which no practical training is possible. The objective is to instill in the pilot the knowledge that almost any terrain can be considered “suitable” for a survivable crash landing if the pilot knows how to use the airplane structure for self-protection and the protection of passengers. TYPES OF EMERGENCY LANDINGS The different types of emergency landings are defined as follows. • Forced landing. An immediate landing, on or off an airport, necessitated by the inability to continue further flight. Atypical example of which is an airplane forced down by engine failure. • Precautionary landing. A premeditated landing, on or off an airport, when further flight is possible but inadvisable. Examples of conditions that may call for a precautionary landing include deteriorating weather, being lost, fuel shortage, and gradually developing engine trouble. • Ditching. A forced or precautionary landing on water. A precautionary landing, generally, is less hazardous than a forced landing because the pilot has more time for terrain selection and the planning of the approach. In addition, the pilot can use power to compensate for errors in judgment or technique. The pilot should be aware that too many situations calling for a precautionary landing are allowed to develop into immediate forced landings, when the pilot uses wishful thinking instead of reason, especially when dealing with a self-inflicted predicament. The non-instrument rated pilot trapped by weather, or the pilot facing imminent fuel exhaustion who does not give any thought to the feasibility of a precautionary landing accepts an extremely hazardous alternative. PSYCHOLOGICAL HAZARDS There are several factors that may interfere with a pilot’s ability to act promptly and properly when faced with an emergency. • Reluctance to accept the emergency situation. A pilot who allows the mind to become paralyzed at the thought that the airplane will be on the ground, in a very short time, regardless of the pilot’s actions or hopes, is severely handicapped in the handling of the emergency. An unconscious desire to delay the dreaded moment may lead to such errors as: failure to lower the nose to maintain flying speed, delay in the selection of the most suitable landing area within reach, and indecision in general. Desperate attempts to correct whatever went wrong, at the expense of airplane control, fall into the same category. • Desire to save the airplane. The pilot who has been conditioned during training to expect to find a relatively safe landing area, whenever the flight instructor closed the throttle for a simulated forced landing, may ignore all basic rules of airmanship to avoid a touchdown in terrain where airplane damage is unavoidable. Typical consequences are: making a 180° turn back to the runway when available altitude is insufficient; stretching the glide without regard for minimum control speed in order to reach a more appealing field; accepting an approach and touchdown situation that leaves no margin for error. The desire to save the airplane, regardless of the risks involved, may be influenced by two other factors: the pilot’s financial stake in the airplane and the Ch 16.qxd 5/7/04 10:30 AM Page 16-1 16-2 certainty that an undamaged airplane implies no bodily harm. There are times, however, when a pilot should be more interested in sacrificing the airplane so that the occupants can safely walk away from it. • Undue concern about getting hurt. Fear is a vital part of the self-preservation mechanism. However, when fear leads to panic, we invite that which we want most to avoid. The survival records favor pilots who maintain their composure and know how to apply the general concepts and procedures that have been developed through the years. The success of an emergency landing is as much a matter of the mind as of skills. BASIC SAFETY CONCEPTS GENERAL A pilot who is faced with an emergency landing in terrain that makes extensive airplane damage inevitable should keep in mind that the avoidance of crash injuries is largely a matter of: (1) keeping vital structure (cockpit/cabin area) relatively intact by using dispensable structure (such as wings, landing gear, and fuselage bottom) to absorb the violence of the stopping process before it affects the occupants, (2) avoiding forceful bodily contact with interior structure. The advantage of sacrificing dispensable structure is demonstrated daily on the highways. A head-on car impact against a tree at 20 miles per hour (m.p.h.) is less hazardous for a properly restrained driver than a similar impact against the driver’s door. Accident experience shows that the extent of crushable structure between the occupants and the principal point of impact on the airplane has a direct bearing on the severity of the transmitted crash forces and, therefore, on survivability. Avoiding forcible contact with interior structure is a matter of seat and body security. Unless the occupant decelerates at the same rate as the surrounding structure, no benefit will be realized from its relative intactness. The occupant will be brought to a stop violently in the form of a secondary collision. Dispensable airplane structure is not the only available energy absorbing medium in an emergency situation. Vegetation, trees, and even manmade structures may be used for this purpose. Cultivated fields with dense crops, such as mature corn and grain, are almost as effective in bringing an airplane to a stop with repairable damage as an emergency arresting device on a runway. [Figure 16-1] Brush and small trees provide considerable cushioning and braking effect without destroying the airplane. When dealing with natural and manmade obstacles with greater strength than the dispensable airplane structure, the pilot must plan the touchdown in such a manner that only nonessential structure is “used up” in the principal slowing down process. The overall severity of a deceleration process is governed by speed (groundspeed) and stopping distance. The most critical of these is speed; doubling the groundspeed means quadrupling the total destructive energy, and vice versa. Even a small change in groundspeed at touchdown—be it as a result of wind or pilot technique—will affect the outcome of a controlled crash. It is important that the actual touchdown during an emergency landing be made at the lowest possible controllable airspeed, using all available aerodynamic devices. Most pilots will instinctively—and correctly—look for the largest available flat and open field for an emergency landing. Actually, very little stopping distance is required if the speed can be dissipated uniformly; that is, if the deceleration forces can be spread evenly over the available distance. This concept is designed into the arresting gear of aircraft carriers that provides a nearly constant stopping force from the moment of hookup. The typical light airplane is designed to provide protection in crash landings that expose the occupants to nine times the acceleration of gravity (9 G) in a forward direction. Assuming a uniform 9 G deceleration, at 50 m.p.h. the required stopping distance is about 9.4 feet. While at 100 m.p.h. the stopping distance is about 37.6 feet—about four times as great. [Figure 16-2] Although these figures are based on an ideal deceleration process, it is interesting to note what can be accomplished in an effectively used short stopping distance. Understanding the need for a firm but uniform deceleration process in very poor terrain enables the pilot to select touchdown conditions that will spread the breakup of dispensable structure over a short distance, thereby reducing the peak deceleration of the cockpit/cabin area. Figure 16-1. Using vegetation to absorb energy. Ch 16.qxd 5/7/04 10:30 AM Page 16-2 16-3 ATTITUDE AND SINK RATE CONTROL The most critical and often the most inexcusable error that can be made in the planning and execution of an emergency landing, even in ideal terrain, is the loss of initiative over the airplane’s attitude and sink rate at touchdown. When the touchdown is made on flat, open terrain, an excessive nose-low pitch attitude brings the risk of “sticking” the nose in the ground. Steep bank angles just before touchdown should also be avoided, as they increase the stalling speed and the likelihood of a wingtip strike. Since the airplane’s vertical component of velocity will be immediately reduced to zero upon ground contact, it must be kept well under control. A flat touchdown at a high sink rate (well in excess of 500 feet per minute (f.p.m.)) on a hard surface can be injurious without destroying the cockpit/cabin structure, especially during gear up landings in low-wing airplanes. A rigid bottom construction of these airplanes may preclude adequate cushioning by structural deformation. Similar impact conditions may cause structural collapse of the overhead structure in high-wing airplanes. On soft terrain, an excessive sink rate may cause digging in of the lower nose structure and severe forward deceleration. TERRAIN SELECTION Apilot’s choice of emergency landing sites is governed by: • The route selected during preflight planning. • The height above the ground when the emergency occurs. • Excess airspeed (excess airspeed can be converted into distance and/or altitude). The only time the pilot has a very limited choice is during the low and slow portion of the takeoff. However, even under these conditions, the ability to change the impact heading only a few degrees may ensure a survivable crash. If beyond gliding distance of a suitable open area, the pilot should judge the available terrain for its energy absorbing capability. If the emergency starts at a considerable height above the ground, the pilot should be more concerned about first selecting the desired general area than a specific spot. Terrain appearances from altitude can be very misleading and considerable altitude may be lost before the best spot can be pinpointed. For this reason, the pilot should not hesitate to discard the original plan for one that is obviously better. However, as a general rule, the pilot should not change his or her mind more than once; a well-executed crash landing in poor terrain can be less hazardous than an uncontrolled touchdown on an established field. AIRPLANE CONFIGURATION Since flaps improve maneuverability at slow speed, and lower the stalling speed, their use during final approach is recommended when time and circumstances permit. However, the associated increase in drag and decrease in gliding distance call for caution in the timing and the extent of their application; premature use of flap, and dissipation of altitude, may jeopardize an otherwise sound plan. A hard and fast rule concerning the position of a retractable landing gear at touchdown cannot be given. In rugged terrain and trees, or during impacts at high sink rate, an extended gear would definitely have a protective effect on the cockpit/cabin area. However, this advantage has to be weighed against the possible side effects of a collapsing gear, such as a ruptured fuel tank. As always, the manufacturer’s recommendations as outlined in the AFM/POH should be followed. When a normal touchdown is assured, and ample stopping distance is available, a gear up landing on level, but soft terrain, or across a plowed field, may result in less airplane damage than a gear down landing. [Figure 16-3] 9g Deceleration 37.6 ft. 50 m.p.h. 100 m.p.h. 9.4 ft. Figure 16-2. Stopping distance vs. groundspeed. Figure 16-3. Intentional gear up landing. Ch 16.qxd 5/7/04 10:30 AM Page 16-3 16-4 Deactivation of the airplane’s electrical system before touchdown reduces the likelihood of a post-crash fire. However, the battery master switch should not be turned off until the pilot no longer has any need for electrical power to operate vital airplane systems. Positive airplane control during the final part of the approach has priority over all other considerations, including airplane configuration and cockpit checks. The pilot should attempt to exploit the power available from an irregularly running engine; however, it is generally better to switch the engine and fuel off just before touchdown. This not only ensures the pilot’s initiative over the situation, but a cooled down engine reduces the fire hazard considerably. APPROACH When the pilot has time to maneuver, the planning of the approach should be governed by three factors. • Wind direction and velocity. • Dimensions and slope of the chosen field. • Obstacles in the final approach path. These three factors are seldom compatible. When compromises have to be made, the pilot should aim for a wind/obstacle/terrain combination that permits a final approach with some margin for error in judgment or technique. A pilot who overestimates the gliding range may be tempted to stretch the glide across obstacles in the approach path. For this reason, it is sometimes better to plan the approach over an unobstructed area, regardless of wind direction. Experience shows that a collision with obstacles at the end of a ground roll, or slide, is much less hazardous than striking an obstacle at flying speed before the touchdown point is reached. TERRAIN TYPES Since an emergency landing on suitable terrain resembles a situation in which the pilot should be familiar through training, only the more unusual situation will be discussed. CONFINED AREAS The natural preference to set the airplane down on the ground should not lead to the selection of an open spot between trees or obstacles where the ground cannot be reached without making a steep descent. Once the intended touchdown point is reached, and the remaining open and unobstructed space is very limited, it may be better to force the airplane down on the ground than to delay touchdown until it stalls (settles). An airplane decelerates faster after it is on the ground than while airborne. Thought may also be given to the desirability of ground-looping or retracting the landing gear in certain conditions. A river or creek can be an inviting alternative in otherwise rugged terrain. The pilot should ensure that the water or creek bed can be reached without snagging the wings. The same concept applies to road landings with one additional reason for caution; manmade obstacles on either side of a road may not be visible until the final portion of the approach. When planning the approach across a road, it should be remembered that most highways, and even rural dirt roads, are paralleled by power or telephone lines. Only a sharp lookout for the supporting structures, or poles, may provide timely warning.

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TREES (FOREST) Although a tree landing is not an attractive prospect, the following general guidelines will help to make the experience survivable. • Use the normal landing configuration (full flaps, gear down). • Keep the groundspeed low by heading into the wind. • Make contact at minimum indicated airspeed, but not below stall speed, and “hang” the airplane in the tree branches in a nose-high landing attitude. Involving the underside of the fuselage and both wings in the initial tree contact provides a more even and positive cushioning effect, while preventing penetration of the windshield. [Figure 16-4] • Avoid direct contact of the fuselage with heavy tree trunks. • Low, closely spaced trees with wide, dense crowns (branches) close to the ground are much better than tall trees with thin tops; the latter allow too much free fall height. (A free fall from 75 feet results in an impact speed of about 40 knots, or about 4,000 f.p.m.) • Ideally, initial tree contact should be symmetrical; that is, both wings should meet equal resistance in the tree branches. This distribution of the load helps to maintain proper airplane attitude. It may also preclude the loss of one wing, which invariably leads to a more rapid and less predictable descent to the ground. • If heavy tree trunk contact is unavoidable once the airplane is on the ground, it is best to involve both wings simultaneously by directing the airplane between two properly spaced trees. Do not attempt this maneuver, however, while still airborne. WATER (DITCHING) AND SNOW A well-executed water landing normally involves less deceleration violence than a poor tree landing or a Ch 16.qxd 5/7/04 10:30 AM Page 16-4 16-5 touchdown on extremely rough terrain. Also an airplane that is ditched at minimum speed and in a normal landing attitude will not immediately sink upon touchdown. Intact wings and fuel tanks (especially when empty) provide floatation for at least several minutes even if the cockpit may be just below the water line in a high-wing airplane. Loss of depth perception may occur when landing on a wide expanse of smooth water, with the risk of flying into the water or stalling in from excessive altitude. To avoid this hazard, the airplane should be “dragged in” when possible. Use no more than intermediate flaps on low-wing airplanes. The water resistance of fully extended flaps may result in asymmetrical flap failure and slowing of the airplane. Keep a retractable gear up unless the AFM/POH advises otherwise. A landing in snow should be executed like a ditching, in the same configuration and with the same regard for loss of depth perception (white out) in reduced visibility and on wide open terrain. ENGINE FAILURE AFTER TAKEOFF (SINGLE-ENGINE) The altitude available is, in many ways, the controlling factor in the successful accomplishment of an emergency landing. If an actual engine failure should occur immediately after takeoff and before a safe maneuvering altitude is attained, it is usually inadvisable to attempt to turn back to the field from where the takeoff was made. Instead, it is safer to immediately establish the proper glide attitude, and select a field directly ahead or slightly to either side of the takeoff path. The decision to continue straight ahead is often difficult to make unless the problems involved in attempting to turn back are seriously considered. In the first place, the takeoff was in all probability made into the wind. To get back to the takeoff field, a downwind turn must be made. This increases the groundspeed and rushes the pilot even more in the performance of procedures and in planning the landing approach. Secondly, the airplane will be losing considerable altitude during the turn and might still be in a bank when the ground is contacted, resulting in the airplane cartwheeling (which would be a catastrophe for the occupants, as well as the airplane). After turning downwind, the apparent increase in groundspeed could mislead the pilot into attempting to prematurely slow down the airplane and cause it to stall. On the other hand, continuing straight ahead or making a slight turn allows the pilot more time to establish a safe landing attitude, and the landing can be made as slowly as possible, but more importantly, the airplane can be landed while under control. Concerning the subject of turning back to the runway following an engine failure on takeoff, the pilot should determine the minimum altitude an attempt of such a maneuver should be made in a particular airplane. Experimentation at a safe altitude should give the pilot an approximation of height lost in a descending 180° turn at idle power. By adding a safety factor of about 25 percent, the pilot should arrive at a practical decision height. The ability to make a 180° turn does not necessarily mean that the departure runway can be reached in a power-off glide; this depends on the wind, the distance traveled during the climb, the height reached, and the glide distance of the airplane without power. The pilot should also remember that a turn back to the departure runway may in fact require more than a 180° change in direction. Consider the following example of an airplane which has taken off and climbed to an altitude of 300 feet AGL when the engine fails. [Figure 16-5 on next page]. After a typical 4 second reaction time, the pilot elects to turn back to the runway. Using a standard rate (3° change in direction per second) turn, it will take 1 minute to turn 180°. At a glide speed of 65 knots, the radius of the turn is 2,100 feet, so at the completion of the turn, the airplane will be 4,200 feet to one side of the runway. The pilot must turn another 45° to head the airplane toward the runway. By this time the total change in direction is 225° equating to 75 seconds plus the 4 second reaction time. If the airplane in a poweroff glide descends at approximately 1,000 f.p.m., it Figure 16-4.Tree landing. Ch 16.qxd 5/7/04 10:30 AM Page 16-5 16-6 will have descended 1,316, feet placing it 1,016 feet below the runway. EMERGENCY DESCENTS An emergency descent is a maneuver for descending as rapidly as possible to a lower altitude or to the ground for an emergency landing. [Figure 16-6] The need for this maneuver may result from an uncontrollable fire, a sudden loss of cabin pressurization, or any other situation demanding an immediate and rapid descent. The objective is to descend the airplane as soon and as rapidly as possible, within the structural limitations of the airplane. Simulated emergency descents should be made in a turn to check for other air traffic below and to look around for a possible emergency landing area. A radio call announcing descent intentions may be appropriate to alert other aircraft in the area. When initiating the descent, a bank of approximately 30 to 45° should be established to maintain positive load factors (“G” forces) on the airplane. Emergency descent training should be performed as recommended by the manufacturer, including the configuration and airspeeds. Except when prohibited by the manufacturer, the power should be reduced to idle, and the propeller control (if equipped) should be placed in the low pitch (or high revolutions per minute (r.p.m.)) position. This will allow the propeller to act as an aerodynamic brake to help prevent an excessive airspeed buildup during the descent. The landing gear and flaps should be extended as recommended by the manufacturer. This will provide maximum drag so that the descent can be made as rapidly as possible, without excessive airspeed. The pilot should not allow the airplane’s airspeed to pass the never-exceed speed (VNE), the maximum landing gear extended speed (VLE), or the maximum flap extended speed (VFE), as applicable. In the case of an engine fire, a high airspeed descent could blow out the fire. However, the weakening of the airplane structure is a major concern and descent at low airspeed would place less stress on the airplane. If the descent is conducted in turbulent conditions, the pilot must also comply with the design maneuvering speed (VA) limitations. The descent should be made at the maximum allowable airspeed consistent with the procedure used. This will provide increased drag and therefore the loss of altitude as quickly as possible. The recovery from an emergency descent should be initiated at a high enough altitude to ensure a safe recovery back to level flight or a precautionary landing. When the descent is established and stabilized during training and practice, the descent should be terminated. Figure 16-5. Turning back to the runway after engine failure. 4,480 Ft. 180° 225° 300 Ft. AGL 1,016 Ft. Ch 16.qxd 5/7/04 10:30 AM Page 16-6 16-7 In airplanes with piston engines, prolonged practice of emergency descents should be avoided to prevent excessive cooling of the engine cylinders. IN-FLIGHT FIRE Afire in flight demands immediate and decisive action. The pilot therefore must be familiar with the procedures outlined to meet this emergency contained in the AFM/POH for the particular airplane. For the purposes of this handbook, in-flight fires are classified as: inflight engine fires, electrical fires, and cabin fires. ENGINE FIRE An in-flight engine compartment fire is usually caused by a failure that allows a flammable substance such as fuel, oil or hydraulic fluid to come in contact with a hot surface. This may be caused by a mechanical failure of the engine itself, an engine-driven accessory, a defective induction or exhaust system, or a broken line. Engine compartment fires may also result from maintenance errors, such as improperly installed/fastened lines and/or fittings resulting in leaks. Engine compartment fires can be indicated by smoke and/or flames coming from the engine cowling area. They can also be indicated by discoloration, bubbling, and/or melting of the engine cowling skin in cases where flames and/or smoke is not visible to the pilot. By the time a pilot becomes aware of an in-flight engine compartment fire, it usually is well developed. Unless the airplane manufacturer directs otherwise in the AFM/POH, the first step on discovering a fire should be to shut off the fuel supply to the engine by placing the mixture control in the idle cut off position and the fuel selector shutoff valve to the OFF position. The ignition switch should be left ON in order to use up the fuel that remains in the fuel lines and components between the fuel selector/shutoff valve and the engine. This procedure may starve the engine compartment of fuel and cause the fire to die naturally. If the flames are snuffed out, no attempt should be made to restart the engine. If the engine compartment fire is oil-fed, as evidenced by thick black smoke, as opposed to a fuel-fed fire which produces bright orange flames, the pilot should consider stopping the propeller rotation by feathering or other means, such as (with constant-speed propellers) placing the pitch control lever to the minimum r.p.m. position and raising the nose to reduce airspeed until the propeller stops rotating. This procedure will stop an engine-driven oil (or hydraulic) pump from continuing to pump the flammable fluid which is feeding the fire. Some light airplane emergency checklists direct the pilot to shut off the electrical master switch. However, the pilot should consider that unless the fire is electrical in nature, or a crash landing is imminent, deactivating the electrical system prevents the use of panel radios for transmitting distress messages and will also cause air traffic control (ATC) to lose transponder returns. Pilots of powerless single-engine airplanes are left with no choice but to make a forced landing. Pilots of twin-engine airplanes may elect to continue the flight to the nearest airport. However, consideration must be given to the possibility that a wing could be seriously impaired and lead to structural failure. Even a brief but intense fire could cause dangerous structural damage. In some cases, the fire could continue to burn under the wing (or engine cowling in the case of a singleengine airplane) out of view of the pilot. Engine compartment fires which appear to have been extinguished have been known to rekindle with changes in airflow pattern and airspeed. The pilot must be familiar with the airplane’s emergency descent procedures. The pilot must bear in mind that: • The airplane may be severely structurally damaged to the point that its ability to remain under control could be lost at any moment. • The airplane may still be on fire and susceptible to explosion. • The airplane is expendable and the only thing that matters is the safety of those on board. ELECTRICAL FIRES The initial indication of an electrical fire is usually the distinct odor of burning insulation. Once an electrical fire is detected, the pilot should attempt to identify the faulty circuit by checking circuit breakers, instruments, avionics, and lights. If the faulty circuit cannot be readily detected and isolated, and flight conditions permit, the battery master switch and alternator/generator switches should be turned off to remove the possible source of the fire. However, any materials which have been ignited may continue to burn. Figure 16-6. Emergency descent. Ch 16.qxd 5/7/04 10:30 AM Page 16-7 16-8 If electrical power is absolutely essential for the flight, an attempt may be made to identify and isolate the faulty circuit by: 1. Turning the electrical master switch OFF. 2. Turning all individual electrical switches OFF. 3. Turning the master switch back ON. 4. Selecting electrical switches that were ON before the fire indication one at a time, permitting a short time lapse after each switch is turned on to check for signs of odor, smoke, or sparks. This procedure, however, has the effect of recreating the original problem. The most prudent course of action is to land as soon as possible. CABIN FIRE Cabin fires generally result from one of three sources: (1) careless smoking on the part of the pilot and/or passengers; (2) electrical system malfunctions; (3) heating system malfunctions. A fire in the cabin presents the pilot with two immediate demands: attacking the fire, and getting the airplane safely on the ground as quickly as possible. A fire or smoke in the cabin should be controlled by identifying and shutting down the faulty system. In many cases, smoke may be removed from the cabin by opening the cabin air vents. This should be done only after the fire extinguisher (if available) is used. Then the cabin air control can be opened to purge the cabin of both smoke and fumes. If smoke increases in intensity when the cabin air vents are opened, they should be immediately closed. This indicates a possible fire in the heating system, nose compartment baggage area (if so equipped), or that the increase in airflow is feeding the fire. On pressurized airplanes, the pressurization air system will remove smoke from the cabin; however, if the smoke is intense, it may be necessary to either depressurize at altitude, if oxygen is available for all occupants, or execute an emergency descent. In unpressurized single-engine and light twin-engine airplanes, the pilot can attempt to expel the smoke from the cabin by opening the foul weather windows. These windows should be closed immediately if the fire becomes more intense. If the smoke is severe, the passengers and crew should use oxygen masks if available, and the pilot should initiate an immediate descent. The pilot should also be aware that on some airplanes, lowering the landing gear and/or wing flaps can aggravate a cabin smoke problem. FLIGHT CONTROL MALFUNCTION/FAILURE TOTAL FLAP FAILURE The inability to extend the wing flaps will necessitate a no-flap approach and landing. In light airplanes a noflap approach and landing is not particularly difficult or dangerous. However, there are certain factors which must be considered in the execution of this maneuver. A no-flap landing requires substantially more runway than normal. The increase in required landing distance could be as much as 50 percent. When flying in the traffic pattern with the wing flaps retracted, the airplane must be flown in a relatively nose-high attitude to maintain altitude, as compared to flight with flaps extended. Losing altitude can be more of a problem without the benefit of the drag normally provided by flaps. A wider, longer traffic pattern may be required in order to avoid the necessity of diving to lose altitude and consequently building up excessive airspeed. On final approach, a nose-high attitude can make it difficult to see the runway. This situation, if not anticipated, can result in serious errors in judgment of height and distance. Approaching the runway in a relatively nose-high attitude can also cause the perception that the airplane is close to a stall. This may cause the pilot to lower the nose abruptly and risk touching down on the nosewheel. With the flaps retracted and the power reduced for landing, the airplane is slightly less stable in the pitch and roll axes. Without flaps, the airplane will tend to float considerably during roundout. The pilot should avoid the temptation to force the airplane onto the runway at an excessively high speed. Neither should the pilot flare excessively, because without flaps this might cause the tail to strike the runway. ASYMMETRIC (SPLIT) FLAP An asymmetric “split” flap situation is one in which one flap deploys or retracts while the other remains in position. The problem is indicated by a pronounced roll toward the wing with the least flap deflection when wing flaps are extended/retracted. The roll encountered in a split flap situation is countered with opposite aileron. The yaw caused by the additional drag created by the extended flap will require substantial opposite rudder, resulting in a cross-control condition. Almost full aileron may be required to maintain a wings-level attitude, especially at the reduced airspeed necessary for approach and landing. The pilot therefore should not attempt to land Ch 16.qxd 5/7/04 10:30 AM Page 16-8 16-9 with a crosswind from the side of the deployed flap, because the additional roll control required to counteract the crosswind may not be available. The pilot must be aware of the difference in stall speeds between one wing and the other in a split flap situation. The wing with the retracted flap will stall considerably earlier than the wing with the deployed flap. This type of asymmetrical stall will result in an uncontrollable roll in the direction of the stalled (clean) wing. If altitude permits, a spin will result. The approach to landing with a split flap condition should be flown at a higher than normal airspeed. The pilot should not risk an asymmetric stall and subsequent loss of control by flaring excessively. Rather, the airplane should be flown onto the runway so that the touchdown occurs at an airspeed consistent with a safe margin above flaps-up stall speed. LOSS OF ELEVATOR CONTROL In many airplanes, the elevator is controlled by two cables: a “down” cable and an “up” cable. Normally, a break or disconnect in only one of these cables will not result in a total loss of elevator control. In most airplanes, a failed cable results in a partial loss of pitch control. In the failure of the “up” elevator cable (the “down” elevator being intact and functional) the control yoke will move aft easily but produce no response. Forward yoke movement, however, beyond the neutral position produces a nosedown attitude. Conversely, a failure of the “down” elevator cable, forward movement of the control yoke produces no effect. The pilot will, however, have partial control of pitch attitude with aft movement. When experiencing a loss of up-elevator control, the pilot can retain pitch control by: • Applying considerable nose-up trim. • Pushing the control yoke forward to attain and maintain desired attitude. • Increasing forward pressure to lower the nose and relaxing forward pressure to raise the nose. • Releasing forward pressure to flare for landing. When experiencing a loss of down-elevator control, the pilot can retain pitch control by: • Applying considerable nosedown trim. • Pulling the control yoke aft to attain and maintain attitude. • Releasing back pressure to lower the nose and increasing back pressure to raise the nose. • Increasing back pressure to flare for landing. Trim mechanisms can be useful in the event of an in-flight primary control failure. For example, if the linkage between the cockpit and the elevator fails in flight, leaving the elevator free to weathervane in the wind, the trim tab can be used to raise or lower the elevator, within limits. The trim tabs are not as effective as normal linkage control in conditions such as low airspeed, but they do have some positive effect— usually enough to bring about a safe landing. If an elevator becomes jammed, resulting in a total loss of elevator control movement, various combinations of power and flap extension offer a limited amount of pitch control. A successful landing under these conditions, however, is problematical. LANDING GEAR MALFUNCTION Once the pilot has confirmed that the landing gear has in fact malfunctioned, and that one or more gear legs refuses to respond to the conventional or alternate methods of gear extension contained in the AFM/POH, there are several methods that may be useful in attempting to force the gear down. One method is to dive the airplane (in smooth air only) to VNE speed (red line on the airspeed indicator) and (within the limits of safety) execute a rapid pull up. In normal category airplanes, this procedure will create a 3.8 G load on the structure, in effect making the landing gear weigh 3.8 times normal. In some cases, this may force the landing gear into the down and locked position. This procedure requires a fine control touch and good feel for the airplane. The pilot must avoid exceeding the design stress limits of the airplane while attempting to lower the landing gear. The pilot must also avoid an accelerated stall and possible loss of control while attention is directed to solving the landing gear problem. Another method that has proven useful in some cases is to induce rapid yawing. After stabilizing at or slightly less than maneuvering speed (VA), the pilot should alternately and aggressively apply rudder in one direction and then the other in rapid sequence. The resulting yawing action may cause the landing gear to fall into place. If all efforts to extend the landing gear have failed, and a gear up landing is inevitable, the pilot should select an airport with crash and rescue facilities. The pilot should not hesitate to request that emergency equipment be standing by. When selecting a landing surface, the pilot should consider that a smooth, hard-surface runway usually causes less damage than rough, unimproved grass strips. A hard surface does, however, create sparks that can ignite fuel. If the airport is so equipped, the pilot Ch 16.qxd 5/7/04 10:30 AM Page 16-9 16-10 can request that the runway surface be foamed. The pilot should consider burning off excess fuel. This will reduce landing speed and fire potential. If the landing gear malfunction is limited to one main landing gear leg, the pilot should consume as much fuel from that side of the airplane as practicable, thereby reducing the weight of the wing on that side. The reduced weight makes it possible to delay the unsupported wing from contacting the surface during the landing roll until the last possible moment. Reduced impact speeds result in less damage. If only one landing gear leg fails to extend, the pilot has the option of landing on the available gear legs, or landing with all the gear legs retracted. Landing on only one main gear usually causes the airplane to veer strongly in the direction of the faulty gear leg after touchdown. If the landing runway is narrow, and/or ditches and obstacles line the runway edge, maximum directional control after touchdown is a necessity. In this situation, a landing with all three gear retracted may be the safest course of action. If the pilot elects to land with one main gear retracted (and the other main gear and nose gear down and locked), the landing should be made in a nose-high attitude with the wings level. As airspeed decays, the pilot should apply whatever aileron control is necessary to keep the unsupported wing airborne as long as possible. [Figure 16-7] Once the wing contacts the surface, the pilot can anticipate a strong yaw in that direction. The pilot must be prepared to use full opposite rudder and aggressive braking to maintain some degree of directional control. When landing with a retracted nosewheel (and the main gear extended and locked) the pilot should hold the nose off the ground until almost full up-elevator has been applied. [Figure 16-8] The pilot should then release back pressure in such a manner that the nose settles slowly to the surface. Applying and holding full up-elevator will result in the nose abruptly dropping to the surface as airspeed decays, possibly resulting in burrowing and/or additional damage. Brake pressure should not be applied during the landing roll unless absolutely necessary to avoid a collision with obstacles. If the landing must be made with only the nose gear extended, the initial contact should be made on the aft fuselage structure with a nose-high attitude. This procedure will help prevent porpoising and/or wheelbarrowing. The pilot should then allow the nosewheel to gradually touch down, using nosewheel steering as necessary for directional control. SYSTEMS MALFUNCTIONS ELECTRICAL SYSTEM The loss of electrical power can deprive the pilot of numerous critical systems, and therefore should not be taken lightly even in day/VFR conditions. Most in-flight failures of the electrical system are located in the generator or alternator. Once the generator or alternator system goes off line, the electrical source in a typical light airplane is a battery. If a warning light or ammeter indicates the probability of an alternator or generator failure in an airplane with only one generating system, however, the pilot may have very little time available from the battery. The rating of the airplane battery provides a clue to how long it may last. With batteries, the higher the amperage load, the less the usable total amperage. Thus a 25-amp hour battery could produce 5 amps per hour for 5 hours, but if the load were increased to 10 amps, it might last only 2 hours. A 40-amp load might discharge the battery fully in about 10 or 15 minutes. Much depends on the battery condition at the time of the system failure. If the battery has been in service for a few years, its power may be reduced substantially because of internal resistance. Or if the system failure was not detected immediately, much of the stored energy may have already been used. It is essential, therefore, that the pilot immediately shed non-essential loads when the generating source fails. [Figure 16-9] The pilot should then plan to land at the nearest suitable airport. What constitutes an “emergency” load following a generating system failure cannot be predetermined, because the actual circumstances will always be somewhat different—for example, whether the flight is VFR or IFR, conducted in day or at night, in clouds or in the clear. Distance to nearest suitable airport can also be a factor. Figure 16-7. Landing with one main gear retracted. Figure 16-8. Landing with nosewheel retracted. Ch 16.qxd 5/7/04 10:30 AM Page 16-10 16-11 The pilot should remember that the electrically powered (or electrically selected) landing gear and flaps will not function properly on the power left in a partially depleted battery. Landing gear and flap motors use up power at rates much greater than most other types of electrical equipment. The result of selecting these motors on a partially depleted battery may well result in an immediate total loss of electrical power. If the pilot should experience a complete in-flight loss of electrical power, the following steps should be taken: • Shed all but the most necessary electricallydriven equipment. • Understand that any loss of electrical power is critical in a small airplane—notify ATC of the situation immediately. Request radar vectors for a landing at the nearest suitable airport. • If landing gear or flaps are electrically controlled or operated, plan the arrival well ahead of time. Expect to make a no-flap landing, and anticipate a manual landing gear extension. PITOT-STATIC SYSTEM The source of the pressure for operating the airspeed indicator, the vertical speed indicator, and the altimeter is the pitot-static system. The major components of the pitot-static system are the impact pressure chamber and lines, and the static pressure chamber and lines, each of which are subject to total or partial blockage by ice, dirt, and/or other foreign matter. Blockage of the pitot-static system will adversely affect instrument operation. [Figure 16-10 on next page] Partial static system blockage is insidious in that it may go unrecognized until a critical phase of flight. During takeoff, climb, and level-off at cruise altitude the altimeter, airspeed indicator, and vertical speed indicator may operate normally. No indication of malfunction may be present until the airplane begins a descent. If the static reference system is severely restricted, but not entirely blocked, as the airplane descends, the static reference pressure at the instruments begins to lag behind the actual outside air pressure. While descending, the altimeter may indicate that the airplane is higher than actual because the obstruction slows the airflow from the static port to the altimeter. The vertical speed indicator confirms the altimeter’s information regarding rate of change, because the reference pressure is not changing at the same rate as the outside air pressure. The airspeed indicator, unable to tell whether it is experiencing more airspeed pitot pressure or less static reference pressure, indicates a higher airspeed than actual. To the pilot, the instruments indicate that the airplane is too high, too fast, and descending at a rate much less than desired. If the pilot levels off and then begins a climb, the altitude indication may still lag. The vertical speed indicator will indicate that the airplane is not climbing as fast as actual. The indicated airspeed, however, may begin to decrease at an alarming rate. The least amount of pitch-up attitude may cause the airspeed needle to indicate dangerously near stall speed. Managing a static system malfunction requires that the pilot know and understand the airplane’s pitot-static system. If a system malfunction is suspected, the pilot should confirm it by opening the alternate static source. This should be done while the airplane is climbing or descending. If the instrument needles move significantly when this is done, a static pressure problem exists and the alternate source should be used during the remainder of the flight. ABNORMAL ENGINE INSTRUMENT INDICATIONS The AFM/POH for the specific airplane contains information that should be followed in the event of any A. Continuous Load Pitot Heating (Operating) Wingtip Lights Heater Igniter **Navigation Receivers **Communications Receivers Fuel Indicator Instrument Lights (overhead) Engine Indicator Compass Light Landing Gear Indicator Flap Indicator B. Intermittent Load Starter Landing Lights Heater Blower Motor Flap Motor Landing Gear Motor Cigarette Lighter Transceiver (keyed) Fuel Boost Pump Cowl Flap Motor Stall Warning Horn ** Amperage for radios varies with equipment. In general, the more recent the model, the less amperage required. NOTE: Panel and indicator lights usually draw less than one amp. 1 4 1 1-4 1-2 1 2 1 1 1 1 1 2 1 1 1 1 1 1 1 1 3.30 3.00 1-20 1-2 each 1-2 each 0.40 0.60 0.30 0.20 0.17 0.17 100.00 17.80 14.00 13.00 10.00 7.50 5-7 2.00 1.00 1.50 Electrical Loads for Light Single Number of Units Total Amperes Figure 16-9. Electrical load for light single. Ch 16.qxd 5/7/04 10:30 AM Page 16-11 16-12 abnormal engine instrument indications. The table on the next page offers generic information on some of the more commonly experienced in-flight abnormal engine instrument indications, their possible causes, and corrective actions. [Table 1] DOOR OPENING IN FLIGHT In most instances, the occurrence of an inadvertent door opening is not of great concern to the safety of a flight, but rather, the pilot’s reaction at the moment the incident happens. A door opening in flight may be accompanied by a sudden loud noise, sustained noise level and possible vibration or buffeting. If a pilot allows himself or herself to become distracted to the point where attention is focused on the open door rather than maintaining control of the airplane, loss of control may result, even though disruption of airflow by the door is minimal. In the event of an inadvertent door opening in flight or on takeoff, the pilot should adhere to the following. • Concentrate on flying the airplane. Particularly in light single- and twin-engine airplanes; a cabin door that opens in flight seldom if ever compromises the airplane’s ability to fly. There may be some handling effects such as roll and/or yaw, but in most instances these can be easily overcome. • If the door opens after lift-off, do not rush to land. Climb to normal traffic pattern altitude, fly a normal traffic pattern, and make a normal landing. • Do not release the seat belt and shoulder harness in an attempt to reach the door. Leave the door alone. Land as soon as practicable, and close the door once safely on the ground. • Remember that most doors will not stay wide open. They will usually bang open, then settle partly closed. A slip towards the door may cause it to open wider; a slip away from the door may push it closed. • Do not panic. Try to ignore the unfamiliar noise and vibration. Also, do not rush. Attempting to get the airplane on the ground as quickly as possible may result in steep turns at low altitude. • Complete all items on the landing checklist. • Remember that accidents are almost never caused by an open door. Rather, an open door accident is caused by the pilot’s distraction or failure to maintain control of the airplane. INADVERTENT VFR FLIGHT INTO IMC GENERAL It is beyond the scope of this handbook to incorporate a course of training in basic attitude instrument flying. This information is contained in FAA-H- 8083-15, Instrument Flying Handbook. Certain pilot certificates and/or associated ratings require training in instrument flying and a demonstration of specific instrument flying tasks on the practical test. Effect of Blocked Pitot/Static Sources on Airspeed, Altimeter and Vertical Speed Indications Pitot Source Blocked One Static Source Blocked Both Static Sources Blocked Both Static and Pitot Sources Blocked Increases with altitude gain; decreases with altitude loss. Decreases with altitude gain; increases with altitude loss. Unaffected Unaffected Does not change with actual gain or loss of altitude. Does not change with actual variations in vertical speed. Inaccurate while sideslipping; very sensitive in turbulence. All indications remain constant, regardless of actual changes in airspeed, altitude and vertical speed. Indicated Airspeed Indicated Altitude Indicated Vertical Speed Figure 16-10. Effects of blocked pitot-static sources. Ch 16.qxd 5/7/04 10:30 AM Page 16-12 16-13 Pilots and flight instructors should refer to FAA-H- 8083-15 for guidance in the performance of these tasks, and to the appropriate practical test standards for information on the standards to which these required tasks must be performed for the particular certificate level and/or rating. The pilot should remember, however, that unless these tasks are practiced on a continuing and regular basis, skill erosion begins almost immediately. In a very short time, the pilot’s assumed level of confidence will be much higher than the performance he or she will actually be able to demonstrate should the need arise. Accident statistics show that the pilot who has not been trained in attitude instrument flying, or one whose instrument skills have eroded, will lose control of the airplane in about 10 minutes once forced to rely solely on instrument reference. The purpose of this section is to provide guidance on practical emergency measures to maintain airplane control for a limited period of time in the event a VFR pilot encounters IMC conditions. The main goal is not precision instrument flying; rather, it is to help the VFR pilot keep the airplane under adequate control until suitable visual references are regained. MALFUNCTION PROBABLE CAUSE CORRECTIVE ACTION Loss of r.p.m. during cruise flight (non-altitude engines) Carburetor or induction icing or air filter clogging Apply carburetor heat. If dirty filter is suspected and non-filtered air is available, switch selector to unfiltered position. Loss of manifold pressure during cruise flight Same as above Same as above. Turbocharger failure Possible exhaust leak. Shut down engine or use lowest practicable power setting. Land as soon as possible. Gain of manifold pressure during cruise flight Throttle has opened, propeller control has decreased r.p.m., or improper method of power reduction Readjust throttle and tighten friction lock. Reduce manifold pressure prior to reducing r.p.m. High oil temperature Oil congealed in cooler Reduce power. Land. Preheat engine. Inadequate engine cooling Reduce power. Increase airspeed. Detonation or preignition Observe cylinder head temperatures for high reading. Reduce manifold pressure. Enrich mixture. Forth coming internal engine faiure Land as soon as possible or feather propeller and stop engine. Land as soon as possible or feather propeller and stop engine. Defective thermostatic oil cooler control Land as soon as possible. Consult maintenance personnel. Low oil temperature Engine not warmed up to operating temperature Warm engine in prescribed manner. High oil pressure Cold oil Same as above. Same as above. Same as above. Same as above. Same as above. Same as above. Possible internal plugging Reduce power. Land as soon as possible. Low oil pressure Broken pressure relief valve Insufficient oil Burned out bearings Fluctuating oil pressure Low oil supply, loose oil lines, defective pressure relief valve Improper cowl flap adjustment Adjust cowl flaps. Adjust cowl flaps. Insufficient airspeed for cooling Increase airspeed. Improper mixture adjustment Adjust mixture. Detonation or preignition Reduce power, enrich mixture, increase cooling airflow. Low cylinder head temperature High cylinder head temperature Excessive cowl flap opening Excessively rich mixture Adjust mixture control. Exteneded glides without clearing engine Clear engine long enough to keep temperatures at minimum range. Ammeter indicating discharge Alternator or generator failure Shed unnecessary electrical load. Land as soon as practicable. Load meter indicating zero Same as above Surging r.p.m. and overspeeding Defective propeller Defective propeller governor Adjust propeller r.p.m. Defective engine Consult maintenance. Consult maintenance personnel. Consult maintenance. Adjust propeller control. Attempt to restore normal operation. Defective tachometer Improper mixture setting Readjust mixture for smooth operation. Adjust mixture for smooth operation. Loss of airspeed in cruise flight with manifold pressure and r.p.m. constant Possible loss of one or more cylinders Land as soon as possible. Rough running engine Improper mixture control setting Defective ignition or valves Detonation or preignition Reduce power, enrich mixture, open cowl flaps to reduce cylinder head temp. Land as soon as practicable. Induction air leak Reduce power. Consult maintenance. Plugged fuel nozzle (Fuel injection) Excessive fuel pressure or fuel flow Lean mixture control. Loss of fuel pressure Engine driven pump failure Turn on boost tanks. No fuel Switch tanks, turn on fuel. Table 1. Ch 16.qxd 5/7/04 10:30 AM Page 16-13 16-14 The first steps necessary for surviving an encounter with instrument meteorological conditions (IMC) by a VFR pilot are: • Recognition and acceptance of the seriousness of the situation and the need for immediate remedial action. • Maintaining control of the airplane. • Obtaining the appropriate assistance in getting the airplane safely on the ground. RECOGNITION A VFR pilot is in IMC conditions anytime he or she is unable to maintain airplane attitude control by reference to the natural horizon, regardless of the circumstances or the prevailing weather conditions. Additionally, the VFR pilot is, in effect, in IMC anytime he or she is inadvertently, or intentionally for an indeterminate period of time, unable to navigate or establish geographical position by visual reference to landmarks on the surface. These situations must be accepted by the pilot involved as a genuine emergency, requiring appropriate action. The pilot must understand that unless he or she is trained, qualified, and current in the control of an airplane solely by reference to flight instruments, he or she will be unable to do so for any length of time. Many hours of VFR flying using the attitude indicator as a reference for airplane control may lull a pilot into a false sense of security based on an overestimation of his or her personal ability to control the airplane solely by instrument reference. In VFR conditions, even though the pilot thinks he or she is controlling the airplane by instrument reference, the pilot also receives an overview of the natural horizon and may subconsciously rely on it more than the cockpit attitude indicator. If the natural horizon were to suddenly disappear, the untrained instrument pilot would be subject to vertigo, spatial disorientation, and inevitable control loss. MAINTAINING AIRPLANE CONTROL Once the pilot recognizes and accepts the situation, he or she must understand that the only way to control the airplane safely is by using and trusting the flight instruments. Attempts to control the airplane partially by reference to flight instruments while searching outside the cockpit for visual confirmation of the information provided by those instruments will result in inadequate airplane control. This may be followed by spatial disorientation and complete control loss. The most important point to be stressed is that the pilot must not panic. The task at hand may seem overwhelming, and the situation may be compounded by extreme apprehension. The pilot therefore must make a conscious effort to relax. The pilot must understand the most important concern— in fact the only concern at this point—is to keep the wings level. An uncontrolled turn or bank usually leads to difficulty in achieving the objectives of any desired flight condition. The pilot will find that good bank control has the effect of making pitch control much easier. The pilot should remember that a person cannot feel control pressures with a tight grip on the controls. Relaxing and learning to “control with the eyes and the brain” instead of only the muscles, usually takes considerable conscious effort. The pilot must believe what the flight instruments show about the airplane’s attitude regardless of what the natural senses tell. The vestibular sense (motion sensing by the inner ear) can and will confuse the pilot. Because of inertia, the sensory areas of the inner ear cannot detect slight changes in airplane attitude, nor can they accurately sense attitude changes which occur at a uniform rate over a period of time. On the other hand, false sensations are often generated, leading the pilot to believe the attitude of the airplane has changed when, in fact, it has not. These false sensations result in the pilot experiencing spatial disorientation. ATTITUDE CONTROL An airplane is, by design, an inherently stable platform and, except in turbulent air, will maintain approximately straight-and-level flight if properly trimmed and left alone. It is designed to maintain a state of equilibrium in pitch, roll, and yaw. The pilot must be aware, however, that a change about one axis will affect the stability of the others. The typical light airplane exhibits a good deal of stability in the yaw axis, slightly less in the pitch axis, and even lesser still in the roll axis. The key to emergency airplane attitude control, therefore, is to: • Trim the airplane with the elevator trim so that it will maintain hands-off level flight at cruise airspeed. • Resist the tendency to over control the airplane. Fly the attitude indicator with fingertip control. No attitude changes should be made unless the flight instruments indicate a definite need for a change. • Make all attitude changes smooth and small, yet with positive pressure. Remember that a small change as indicated on the horizon bar corresponds to a proportionately much larger change in actual airplane attitude. • Make use of any available aid in attitude control such as autopilot or wing leveler. Ch 16.qxd 5/7/04 10:30 AM Page 16-14 16-15 The primary instrument for attitude control is the attitude indicator. [Figure 16-11] Once the airplane is trimmed so that it will maintain hands-off level flight at cruise airspeed, that airspeed need not vary until the airplane must be slowed for landing. All turns, climbs and descents can and should be made at this airspeed. Straight flight is maintained by keeping the wings level using “fingertip pressure” on the control wheel. Any pitch attitude change should be made by using no more than one bar width up or down. TURNS Turns are perhaps the most potentially dangerous maneuver for the untrained instrument pilot for two reasons. • The normal tendency of the pilot to over control, leading to steep banks and the possibility of a “graveyard spiral.” • The inability of the pilot to cope with the instability resulting from the turn. When a turn must be made, the pilot must anticipate and cope with the relative instability of the roll axis. The smallest practical bank angle should be used—in any case no more than 10° bank angle. [Figure 16-12] A shallow bank will take very little vertical lift from the wings resulting in little if any deviation in altitude. It may be helpful to turn a few degrees and then return to level flight, if a large change in heading must be made. Repeat the process until the desired heading is reached. This process may relieve the progressive overbanking that often results from prolonged turns. CLIMBS If a climb is necessary, the pilot should raise the miniature airplane on the attitude indicator no more than one bar width and apply power. [Figure 16-13] The pilot should not attempt to attain a specific climb speed but accept whatever speed results. The objective is to deviate as little as possible from level flight attitude in order to disturb the airplane’s equilibrium as little as possible. If the airplane is properly trimmed, it will assume a nose-up attitude on its own commensurate with the amount of power applied. Torque and P-factor will cause the airplane to have a Figure 16-11. Attitude indicator. Figure 16-12. Level turn. Figure 16-13. Level climb. Ch 16.qxd 5/7/04 10:30 AM Page 16-15 16-16 tendency to bank and turn to the left. This must be anticipated and compensated for. If the initial power application results in an inadequate rate of climb, power should be increased in increments of 100 r.p.m. or 1 inch of manifold pressure until the desired rate of climb is attained. Maximum available power is seldom necessary. The more power used the more the airplane will want to bank and turn to the left. Resuming level flight is accomplished by first decreasing pitch attitude to level on the attitude indicator using slow but deliberate pressure, allowing airspeed to increase to near cruise value, and then decreasing power. DESCENTS Descents are very much the opposite of the climb procedure if the airplane is properly trimmed for hands-off straight-and-level flight. In this configuration, the airplane requires a certain amount of thrust to maintain altitude. The pitch attitude is controlling the airspeed. The engine power, therefore, (translated into thrust by the propeller) is maintaining the selected altitude. Following a power reduction, however slight, there will be an almost imperceptible decrease in airspeed. However, even a slight change in speed results in less down load on the tail, whereupon the designed nose heaviness of the airplane causes it to pitch down just enough to maintain the airspeed for which it was trimmed. The airplane will then descend at a rate directly proportionate to the amount of thrust that has been removed. Power reductions should be made in increments of 100 r.p.m. or 1 inch of manifold pressure and the resulting rate of descent should never exceed 500 f.p.m. The wings should be held level on the attitude indicator, and the pitch attitude should not exceed one bar width below level. [Figure 16-14] COMBINED MANEUVERS Combined maneuvers, such as climbing or descending turns should be avoided if at all possible by an untrained instrument pilot already under the stress of an emergency situation. Combining maneuvers will only compound the problems encountered in individual maneuvers and increase the risk of control loss. Remember that the objective is to maintain airplane control by deviating as little as possible from straightand- level flight attitude and thereby maintaining as much of the airplane’s natural equilibrium as possible. When being assisted by air traffic controllers from the ground, the pilot may detect a sense of urgency as he or she is being directed to change heading and/or altitude. This sense of urgency reflects a normal concern for safety on the part of the controller. But the pilot must not let this prompt him or her to attempt a maneuver that could result in loss of control. TRANSITION TO VISUAL FLIGHT One of the most difficult tasks a trained and qualified instrument pilot must contend with is the transition from instrument to visual flight prior to landing. For the untrained instrument pilot, these difficulties are magnified. The difficulties center around acclimatization and orientation. On an instrument approach the trained instrument pilot must prepare in advance for the transition to visual flight. The pilot must have a mental picture of what he or she expects to see once the transition to visual flight is made and quickly acclimatize to the new environment. Geographical orientation must also begin before the transition as the pilot must visualize where the airplane will be in relation to the airport/runway when the transition occurs so that the approach and landing may be completed by visual reference to the ground. In an ideal situation the transition to visual flight is made with ample time, at a sufficient altitude above terrain, and to visibility conditions sufficient to accommodate acclimatization and geographical orientation. This, however, is not always the case. The untrained instrument pilot may find the visibility still limited, the terrain completely unfamiliar, and altitude above terrain such that a “normal” airport traffic pattern and landing approach is not possible. Additionally, the pilot will most likely be under considerable self-induced psychological pressure to Figure 16-14. Level descent. Ch 16.qxd 5/7/04 10:30 AM Page 16-16 16-17 get the airplane on the ground. The pilot must take this into account and, if possible, allow time to become acclimatized and geographically oriented before attempting an approach and landing, even if it means flying straight and level for a time or circling the airport. This is especially true at night. Ch 16.qxd 5/7/04 10:30 AM Page 16-17 16-18 Ch 16.qxd 5/7/04 10:30 AM Page 16-18 100-HOUR INSPECTION— An inspection, identical in scope to an annual inspection. Must be conducted every 100 hours of flight on aircraft of under 12,500 pounds that are used for hire. ABSOLUTE ALTITUDE— The vertical distance of an airplane above the terrain, or above ground level (AGL). ABSOLUTE CEILING— The altitude at which a climb is no longer possible. ACCELERATE-GO DISTANCE— The distance required to accelerate to V1 with all engines at takeoff power, experience an engine failure at V1 and continue the takeoff on the remaining engine(s). The runway required includes the distance required to climb to 35 feet by which time V2 speed must be attained. ACCELERATE-STOP DISTANCE—The distance required to accelerate to V1 with all engines at takeoff power, experience an engine failure at V1, and abort the takeoff and bring the airplane to a stop using braking action only (use of thrust reversing is not considered). ACCELERATION—Force involved in overcoming inertia, and which may be defined as a change in velocity per unit of time. ACCESSORIES—Components that are used with an engine, but are not a part of the engine itself. Units such as magnetos, carburetors, generators, and fuel pumps are commonly installed engine accessories. ADJUSTABLE STABILIZER— A stabilizer that can be adjusted in flight to trim the airplane, thereby even a trim tab, which provides aerodynamic force when it interacts with a moving stream of air. AIRMANSHIP SKILLS—The skills of coordination, timing, control touch, and speed sense in addition to the motor skills required to fly an aircraft. AIRMANSHIP— A sound acquaintance with the principles of flight, the ability to operate an airplane with competence and precision both on the ground and in the air, and the exercise of sound judgment that results in optimal operational safety and efficiency. AIRPLANE FLIGHT MANUAL (AFM)—A document developed by the airplane manufacturer and approved by the Federal Aviation Administration (FAA). It is specific to a particular make and model airplane by serial number and it contains operating procedures and limitations. AIRPLANE OWNER/ INFORMATION MANUAL—A document developed by the airplane manufacturer containing general information about the make and model of an airplane. The airplane owner’s manual is not FAA-approved and is not specific to a particular serial numbered airplane. This manual is not kept current, and therefore cannot be substituted for the AFM/POH. AIRPORT/FACILITY DIRECTORY— A publication designed primarily as a pilot’s operational manual containing all airports, seaplane bases, and heliports open to the public including communications data, navigational facilities, and certain special notices and procedures. This publication is issued in seven volumes according to geographical area. allowing the airplane to fly hands-off at any given airspeed. ADVERSE YAW—A condition of flight in which the nose of an airplane tends to yaw toward the outside of the turn. This is caused by the higher induced drag on the outside wing, which is also producing more lift. Induced drag is a by-product of the lift associated with the outside wing. AERODYNAMIC CEILING— The point (altitude) at which, as the indicated airspeed decreases with altitude, it progressively merges with the low speed buffet boundary where prestall buffet occurs for the airplane at a load factor of 1.0 G. AERODYNAMICS—The science of the action of air on an object, and with the motion of air on other gases. Aerodynamics deals with the production of lift by the aircraft, the relative wind, and the atmosphere. AILERONS—Primary flight control surfaces mounted on the trailing edge of an airplane wing, near the tip. Ailerons control roll about the longitudinal axis. AIR START—The act or instance of starting an aircraft’s engine while in flight, especially a jet engine after flameout. AIRCRAFT LOGBOOKS— Journals containing a record of total operating time, repairs, alterations or inspections performed, and all Airworthiness Directive (AD) notes complied with. A maintenance logbook should be kept for the airframe, each engine, and each propeller. AIRFOIL—An airfoil is any surface, such as a wing, propeller, rudder, or G-1 Glossary.qxd 5/7/04 10:46 AM Page G-1 G-2 AIRWORTHINESS—A condition in which the aircraft conforms to its type certificated design including supplemental type certificates, and field approved alterations. The aircraft must also be in a condition for safe flight as determined by annual, 100 hour, preflight and any other required inspections. AIRWORTHINESS CERTIFICATE— A certificate issued by the FAA to all aircraft that have been proven to meet the minimum standards set down by the Code of Federal Regulations. AIRWORTHINESS DIRECTIVE—A regulatory notice sent out by the FAA to the registered owner of an aircraft informing the owner of a condition that prevents the aircraft from continuing to meet its conditions for airworthiness. Airworthiness Directives (AD notes) must be complied with within the required time limit, and the fact of compliance, the date of compliance, and the method of compliance must be recorded in the aircraft’s maintenance records. ALPHA MODE OF OPERATION—The operation of a turboprop engine that includes all of the flight operations, from takeoff to landing. Alpha operation is typically between 95 percent to 100 percent of the engine operating speed. ALTERNATE AIR—A device which opens, either automatically or manually, to allow induction airflow to continue should the primary induction air opening become blocked. ALTERNATE STATIC SOURCE— A manual port that when opened allows the pitot static instruments to sense static pressure from an alternate location should the primary static port become blocked. ALTERNATOR/GENERATOR—A device that uses engine power to generate electrical power. ALTIMETER—A flight instrument that indicates altitude by sensing pressure changes. pitch, which is the up and down movement of the airplane’s nose. ATTITUDE— The position of an aircraft as determined by the relationship of its axes and a reference, usually the earth’s horizon. AUTOKINESIS—This is caused by staring at a single point of light against a dark background for more than a few seconds. After a few moments, the light appears to move on its own. AUTOPILOT—An automatic flight control system which keeps an aircraft in level flight or on a set course. Automatic pilots can be directed by the pilot, or they may be coupled to a radio navigation signal. AXES OF AN AIRCRAFT—Three imaginary lines that pass through an aircraft’s center of gravity. The axes can be considered as imaginary axles around which the aircraft turns. The three axes pass through the center of gravity at 90° angles to each other. The axis from nose to tail is the longitudinal axis, the axis that passes from wingtip to wingtip is the lateral axis, and the axis that passes vertically through the center of gravity is the vertical axis. AXIAL FLOW COMPRESSOR— Atype of compressor used in a turbine engine in which the airflow through the compressor is essentially linear. An axial-flow compressor is made up of several stages of alternate rotors and stators. The compressor ratio is determined by the decrease in area of the succeeding stages. BACK SIDE OF THE POWER CURVE— Flight regime in which flight at a higher airspeed requires a lower power setting and a lower airspeed requires a higher power setting in order to maintain altitude. BALKED LANDING— A go-around. BALLAST—Removable or permanently installed weight in an aircraft ALTITUDE (AGL)—The actual height above ground level (AGL) at which the aircraft is flying. ALTITUDE (MSL)—The actual height above mean sea level (MSL) at which the aircraft is flying. ALTITUDE CHAMBER—A device that simulates high altitude conditions by reducing the interior pressure. The occupants will suffer from the same physiological conditions as flight at high altitude in an unpressurized aircraft. ALTITUDE ENGINE— A reciprocating aircraft engine having a rated takeoff power that is producible from sea level to an established higher altitude. ANGLE OF ATTACK—The acute angle between the chord line of the airfoil and the direction of the relative wind. ANGLE OF INCIDENCE— The angle formed by the chord line of the wing and a line parallel to the longitudinal axis of the airplane. ANNUAL INSPECTION— A complete inspection of an aircraft and engine, required by the Code of Federal Regulations, to be accomplished every 12 calendar months on all certificated aircraft. Only an A&P technician holding an Inspection Authorization can conduct an annual inspection. ANTI-ICING—The prevention of the formation of ice on a surface. Ice may be prevented by using heat or by covering the surface with a chemical that prevents water from reaching the surface. Anti-icing should not be confused with deicing, which is the removal of ice after it has formed on the surface. ATTITUDE INDICATOR— An instrument which uses an artificial horizon and miniature airplane to depict the position of the airplane in relation to the true horizon. The attitude indicator senses roll as well as Glossary.qxd 5/7/04 10:46 AM Page G-2 G-3 used to bring the center of gravity into the allowable range. BALLOON—The result of a too aggressive flare during landing causing the aircraft to climb. BASIC EMPTY WEIGHT (GAMA)—Basic empty weight includes the standard empty weight plus optional and special equipment that has been installed. BEST ANGLE OF CLIMB (VX)— The speed at which the aircraft will produce the most gain in altitude in a given distance. BEST GLIDE—The airspeed in which the aircraft glides the furthest for the least altitude lost when in non-powered flight. BEST RATE OF CLIMB (VY)— The speed at which the aircraft will produce the most gain in altitude in the least amount of time. BLADE FACE—The flat portion of a propeller blade, resembling the bottom portion of an airfoil. BLEED AIR—Compressed air tapped from the compressor stages of a turbine engine by use of ducts and tubing. Bleed air can be used for deice, anti-ice, cabin pressurization, heating, and cooling systems. BLEED VALVE—In a turbine engine, a flapper valve, a popoff valve, or a bleed band designed to bleed off a portion of the compressor air to the atmosphere. Used to maintain blade angle of attack and provide stall-free engine acceleration and deceleration. BOOST PUMP—An electrically driven fuel pump, usually of the centrifugal type, located in one of the fuel tanks. It is used to provide fuel to the engine for starting and providing fuel pressure in the event of failure of the engine driven pump. It also pressurizes the fuel lines to prevent vapor lock. CAMBERED—The camber of an airfoil is the characteristic curve of its upper and lower surfaces. The upper camber is more pronounced, while the lower camber is comparatively flat. This causes the velocity of the airflow immediately above the wing to be much higher than that below the wing. CARBURETOR ICE— Ice that forms inside the carburetor due to the temperature drop caused by the vaporization of the fuel. Induction system icing is an operational hazard because it can cut off the flow of the fuel/air charge or vary the fuel/air ratio. CARBURETOR—1. Pressure: A hydromechanical device employing a closed feed system from the fuel pump to the discharge nozzle. It meters fuel through fixed jets according to the mass airflow through the throttle body and discharges it under a positive pressure. Pressure carburetors are distinctly different from float-type carburetors, as they do not incorporate a vented float chamber or suction pickup from a discharge nozzle located in the venturi tube. 2. Float-type: Consists essentially of a main air passage through which the engine draws its supply of air, a mechanism to control the quantity of fuel discharged in relation to the flow of air, and a means of regulating the quantity of fuel/air mixture delivered to the engine cylinders. CASCADE REVERSER—A thrust reverser normally found on turbofan engines in which a blocker door and a series of cascade vanes are used to redirect exhaust gases in a forward direction. CENTER OF GRAVITY (CG)— The point at which an airplane would balance if it were possible to suspend it at that point. It is the mass center of the airplane, or the theoretical point at which the entire weight of the airplane is assumed to be concentrated. It may be expressed in inches from the reference datum, or in percent of mean aerodynamic chord (MAC). The location depends on the distribution of weight in the airplane. BUFFETING—The beating of an aerodynamic structure or surface by unsteady flow, gusts, etc.; the irregular shaking or oscillation of a vehicle component owing to turbulent air or separated flow. BUS BAR—An electrical power distribution point to which several circuits may be connected. It is often a solid metal strip having a number of terminals installed on it. BUS TIE—A switch that connects two or more bus bars. It is usually used when one generator fails and power is lost to its bus. By closing the switch, the operating generator powers both busses. BYPASS AIR—The part of a turbofan’s induction air that bypasses the engine core. BYPASS RATIO—The ratio of the mass airflow in pounds per second through the fan section of a turbofan engine to the mass airflow that passes through the gas generator portion of the engine. Or, the ratio between fan mass airflow (lb/sec.) and core engine mass airflow (lb/sec.). CABIN PRESSURIZATION—A condition where pressurized air is forced into the cabin simulating pressure conditions at a much lower altitude and increasing the aircraft occupants comfort. CALIBRATED AIRSPEED (CAS)—Indicated airspeed corrected for installation error and instrument error. Although manufacturers attempt to keep airspeed errors to a minimum, it is not possible to eliminate all errors throughout the airspeed operating range. At certain airspeeds and with certain flap settings, the installation and instrument errors may total several knots. This error is generally greatest at low airspeeds. In the cruising and higher airspeed ranges, indicated airspeed and calibrated airspeed are approximately the same. Refer to the airspeed calibration chart to correct for possible airspeed errors. Glossary.qxd 5/7/04 10:46 AM Page G-3 G-4 CENTER-OF-GRAVITY LIMITS—The specified forward and aft points within which the CG must be located during flight. These limits are indicated on pertinent airplane specifications. CENTER-OF-GRAVITY RANGE—The distance between the forward and aft CG limits indicated on pertinent airplane specifications. CENTRIFUGAL FLOW COMPRESSOR— An impeller-shaped device that receives air at its center and slings air outward at high velocity into a diffuser for increased pressure. Also referred to as a radial outflow compressor. CHORD LINE—An imaginary straight line drawn through an airfoil from the leading edge to the trailing edge. CIRCUIT BREAKER— A circuit-protecting device that opens the circuit in case of excess current flow. A circuit breakers differs from a fuse in that it can be reset without having to be replaced. CLEAR AIR TURBULENCE— Turbulence not associated with any visible moisture. CLIMB GRADIENT—The ratio between distance traveled and altitude gained. COCKPIT RESOURCE MANAGEMENT—Techniques designed to reduce pilot errors and manage errors that do occur utilizing cockpit human resources. The assumption is that errors are going to happen in a complex system with error-prone humans. COEFFICIENT OF LIFT—See LIFT COEFFICIENT. COFFIN CORNER—The flight regime where any increase in airspeed will induce high speed mach buffet and any decrease in airspeed will induce low speed mach buffet. CONDITION LEVER—In a turbine engine, a powerplant control that controls the flow of fuel to the engine. The condition lever sets the desired engine r.p.m. within a narrow range between that appropriate for ground and flight operations. CONFIGURATION—This is a general term, which normally refers to the position of the landing gear and flaps. CONSTANT SPEED PROPELLER— A controllablepitch propeller whose pitch is automatically varied in flight by a governor to maintain a constant r.p.m. in spite of varying air loads. CONTROL TOUCH—The ability to sense the action of the airplane and its probable actions in the immediate future, with regard to attitude and speed variations, by sensing and evaluation of varying pressures and resistance of the control surfaces transmitted through the cockpit flight controls. CONTROLLABILITY—A measure of the response of an aircraft relative to the pilot’s flight control inputs. CONTROLLABLE PITCH PROPELLER—Apropeller in which the blade angle can be changed during flight by a control in the cockpit. CONVENTIONAL LANDING GEAR—Landing gear employing a third rear-mounted wheel. These airplanes are also sometimes referred to as tailwheel airplanes. COORDINATED FLIGHT— Application of all appropriate flight and power controls to prevent slipping or skidding in any flight condition. COORDINATION—The ability to use the hands and feet together subconsciously and in the proper relationship to produce desired results in the airplane. CORE AIRFLOW—Air drawn into the engine for the gas generator. COMBUSTION CHAMBER—The section of the engine into which fuel is injected and burned. COMMON TRAFFIC ADVISORY FREQUENCY—The common frequency used by airport traffic to announce position reports in the vicinity of the airport. COMPLEX AIRCRAFT— An aircraft with retractable landing gear, flaps, and a controllable-pitch propeller, or is turbine powered. COMPRESSION RATIO—1. In a reciprocating engine, the ratio of the volume of an engine cylinder with the piston at the bottom center to the volume with the piston at top center. 2. In a turbine engine, the ratio of the pressure of the air at the discharge to the pressure of air at the inlet. COMPRESSOR BLEED AIR— See BLEED AIR. COMPRESSOR BLEED VALVES—See BLEED VALVE. COMPRESSOR SECTION— The section of a turbine engine that increases the pressure and density of the air flowing through the engine. COMPRESSOR STALL—In gas turbine engines, a condition in an axial-flow compressor in which one or more stages of rotor blades fail to pass air smoothly to the succeeding stages. Astall condition is caused by a pressure ratio that is incompatible with the engine r.p.m. Compressor stall will be indicated by a rise in exhaust temperature or r.p.m. fluctuation, and if allowed to continue, may result in flameout and physical damage to the engine. COMPRESSOR SURGE—Asevere compressor stall across the entire compressor that can result in severe damage if not quickly corrected. This condition occurs with a complete stoppage of airflow or a reversal of airflow. Glossary.qxd 5/7/04 10:46 AM Page G-4 G-5 COWL FLAPS—Devices arranged around certain air-cooled engine cowlings which may be opened or closed to regulate the flow of air around the engine. CRAB—A flight condition in which the nose of the airplane is pointed into the wind a sufficient amount to counteract a crosswind and maintain a desired track over the ground. CRAZING—Small fractures in aircraft windshields and windows caused from being exposed to the ultraviolet rays of the sun and temperature extremes. CRITICAL ALTITUDE— The maximum altitude under standard atmospheric conditions at which a turbocharged engine can produce its rated horsepower. CRITICAL ANGLE OF ATTACK—The angle of attack at which a wing stalls regardless of airspeed, flight attitude, or weight. CRITICAL ENGINE—The engine whose failure has the most adverse effect on directional control. CROSS CONTROLLED— A condition where aileron deflection is in the opposite direction of rudder deflection. CROSSFEED—Asystem that allows either engine on a twin-engine airplane to draw fuel from any fuel tank. CROSSWIND COMPONENT— The wind component, measured in knots, at 90° to the longitudinal axis of the runway. CURRENT LIMITER—A device that limits the generator output to a level within that rated by the generator manufacturer. DATUM (REFERENCE DATUM)—An imaginary vertical plane or line from which all measurements of moment arm are taken. The datum is established by the manufacturer. Once the datum has been selected, all moment arms and parasite drag to compensate for the additional induced drag caused by the down aileron. This balancing of the drag forces helps minimize adverse yaw. DIFFUSION—Reducing the velocity of air causing the pressure to increase. DIRECTIONAL STABILITY— Stability about the vertical axis of an aircraft, whereby an aircraft tends to return, on its own, to flight aligned with the relative wind when disturbed from that equilibrium state. The vertical tail is the primary contributor to directional stability, causing an airplane in flight to align with the relative wind. DITCHING—Emergency landing in water. DOWNWASH— Air deflected perpendicular to the motion of the airfoil. DRAG—An aerodynamic force on a body acting parallel and opposite to the relative wind. The resistance of the atmosphere to the relative motion of an aircraft. Drag opposes thrust and limits the speed of the airplane. DRAG CURVE— A visual representation of the amount of drag of an aircraft at various airspeeds. DRIFT ANGLE—Angle between heading and track. DUCTED-FAN ENGINE— An engine-propeller combination that has the propeller enclosed in a radial shroud. Enclosing the propeller improves the efficiency of the propeller. DUTCH ROLL—A combination of rolling and yawing oscillations that normally occurs when the dihedral effects of an aircraft are more powerful than the directional stability. Usually dynamically stable but objectionable in an airplane because of the oscillatory nature. the location of CG range are measured from this point. DECOMPRESSION SICKNESS— A condition where the low pressure at high altitudes allows bubbles of nitrogen to form in the blood and joints causing severe pain. Also known as the bends. DEICER BOOTS—Inflatable rubber boots attached to the leading edge of an airfoil. They can be sequentially inflated and deflated to break away ice that has formed over their surface. DEICING—Removing ice after it has formed. DELAMINATION—The separation of layers. DENSITY ALTITUDE— This altitude is pressure altitude corrected for variations from standard temperature. When conditions are standard, pressure altitude and density altitude are the same. If the temperature is above standard, the density altitude is higher than pressure altitude. If the temperature is below standard, the density altitude is lower than pressure altitude. This is an important altitude because it is directly related to the airplane’s performance. DESIGNATED PILOT EXAMINER (DPE)—An individual designated by the FAA to administer practical tests to pilot applicants. DETONATION— The sudden release of heat energy from fuel in an aircraft engine caused by the fuel-air mixture reaching its critical pressure and temperature. Detonation occurs as a violent explosion rather than a smooth burning process. DEWPOINT—The temperature at which air can hold no more water. DIFFERENTIAL AILERONS— Control surface rigged such that the aileron moving up moves a greater distance than the aileron moving down. The up aileron produces extra Glossary.qxd 5/7/04 10:46 AM Page G-5 G-6 DYNAMIC HYDROPLANING—A condition that exists when landing on a surface with standing water deeper than the tread depth of the tires. When the brakes are applied, there is a possibility that the brake will lock up and the tire will ride on the surface of the water, much like a water ski. When the tires are hydroplaning, directional control and braking action are virtually impossible. An effective anti-skid system can minimize the effects of hydroplaning. DYNAMIC STABILITY— The property of an aircraft that causes it, when disturbed from straight-andlevel flight, to develop forces or moments that restore the original condition of straight and level. ELECTRICAL BUS— See BUS BAR. ELECTROHYDRAULIC— Hydraulic control which is electrically actuated. ELEVATOR— The horizontal, movable primary control surface in the tail section, or empennage, of an airplane. The elevator is hinged to the trailing edge of the fixed horizontal stabilizer. EMERGENCY LOCATOR TRANSMITTER—A small, selfcontained radio transmitter that will automatically, upon the impact of a crash, transmit an emergency signal on 121.5, 243.0, or 406.0 MHz. EMPENNAGE—The section of the airplane that consists of the vertical stabilizer, the horizontal stabilizer, and the associated control surfaces. ENGINE PRESSURE RATIO (EPR)—The ratio of turbine discharge pressure divided by compressor inlet pressure that is used as an indication of the amount of thrust being developed by a turbine engine. ENVIRONMENTAL SYSTEMS— In an aircraft, the systems, including the supplemental oxygen systems, air conditioning systems, heaters, and FIXED SHAFT TURBOPROP ENGINE—A turboprop engine where the gas producer spool is directly connected to the output shaft. FIXED-PITCH PROPELLERS— Propellers with fixed blade angles. Fixed-pitch propellers are designed as climb propellers, cruise propellers, or standard propellers. FLAPS—Hinged portion of the trailing edge between the ailerons and fuselage. In some aircraft, ailerons and flaps are interconnected to produce full-span “flaperons.” In either case, flaps change the lift and drag on the wing. FLAT PITCH— A propeller configuration when the blade chord is aligned with the direction of rotation. FLICKER VERTIGO— A disorientating condition caused from flickering light off the blades of the propeller. FLIGHT DIRECTOR—An automatic flight control system in which the commands needed to fly the airplane are electronically computed and displayed on a flight instrument. The commands are followed by the human pilot with manual control inputs or, in the case of an autopilot system, sent to servos that move the flight controls. FLIGHT IDLE—Engine speed, usually in the 70-80 percent range, for minimum flight thrust. FLOATING—A condition when landing where the airplane does not settle to the runway due to excessive airspeed. FORCE (F)—The energy applied to an object that attempts to cause the object to change its direction, speed, or motion. In aerodynamics, it is expressed as F, T (thrust), L (lift), W (weight), or D (drag), usually in pounds. FORM DRAG—The part of parasite drag on a body resulting from the pressurization systems, which make it possible for an occupant to function at high altitude. EQUILIBRIUM—A condition that exists within a body when the sum of the moments of all of the forces acting on the body is equal to zero. In aerodynamics, equilibrium is when all opposing forces acting on an aircraft are balanced (steady, unaccelerated flight conditions). EQUIVALENT SHAFT HORSEPOWER (ESHP)— A measurement of the total horsepower of a turboprop engine, including that provided by jet thrust. EXHAUST GAS TEMPERATURE (EGT)—The temperature of the exhaust gases as they leave the cylinders of a reciprocating engine or the turbine section of a turbine engine. EXHAUST MANIFOLD—The part of the engine that collects exhaust gases leaving the cylinders. EXHAUST—The rear opening of a turbine engine exhaust duct. The nozzle acts as an orifice, the size of which determines the density and velocity of the gases as they emerge from the engine. FALSE HORIZON—An optical illusion where the pilot confuses a row of lights along a road or other straight line as the horizon. FALSE START— See HUNG START. FEATHERING PROPELLER (FEATHERED)—A controllable pitch propeller with a pitch range sufficient to allow the blades to be turned parallel to the line of flight to reduce drag and prevent further damage to an engine that has been shut down after a malfunction. FIXATION— A psychological condition where the pilot fixes attention on a single source of information and ignores all other sources. Glossary.qxd 5/7/04 10:46 AM Page G-6 G-7 integrated effect of the static pressure acting normal to its surface resolved in the drag direction. FORWARD SLIP—A slip in which the airplane’s direction of motion continues the same as before the slip was begun. In a forward slip, the airplane’s longitudinal axis is at an angle to its flightpath. FREE POWER TURBINE ENGINE—A turboprop engine where the gas producer spool is on a separate shaft from the output shaft. The free power turbine spins independently of the gas producer and drives the output shaft. FRICTION DRAG—The part of parasitic drag on a body resulting from viscous shearing stresses over its wetted surface. FRISE-TYPE AILERON—Aileron having the nose portion projecting ahead of the hinge line. When the trailing edge of the aileron moves up, the nose projects below the wing’s lower surface and produces some parasite drag, decreasing the amount of adverse yaw. FUEL CONTROL UNIT— The fuel-metering device used on a turbine engine that meters the proper quantity of fuel to be fed into the burners of the engine. It integrates the parameters of inlet air temperature, compressor speed, compressor discharge pressure, and exhaust gas temperature with the position of the cockpit power control lever. FUEL EFFICIENCY—Defined as the amount of fuel used to produce a specific thrust or horsepower divided by the total potential power contained in the same amount of fuel. FUEL HEATERS—A radiator-like device which has fuel passing through the core. A heat exchange occurs to keep the fuel temperature above the freezing point of water so that entrained water does not form ice crystals, which could block fuel flow. FUEL INJECTION— A fuel metering system used on some aircraft reciprocating engines in GO-AROUND— Terminating a landing approach. GOVERNING RANGE—The range of pitch a propeller governor can control during flight. GOVERNOR—A control which limits the maximum rotational speed of a device. GROSS WEIGHT— The total weight of a fully loaded aircraft including the fuel, oil, crew, passengers, and cargo. GROUND ADJUSTABLE TRIM TAB—A metal trim tab on a control surface that is not adjustable in flight. Bent in one direction or another while on the ground to apply trim forces to the control surface. GROUND EFFECT—A condition of improved performance encountered when an airplane is operating very close to the ground. When an airplane’s wing is under the influence of ground effect, there is a reduction in upwash, downwash, and wingtip vortices. As a result of the reduced wingtip vortices, induced drag is reduced. GROUND IDLE—Gas turbine engine speed usually 60-70 percent of the maximum r.p.m. range, used as a minimum thrust setting for ground operations. GROUND LOOP—A sharp, uncontrolled change of direction of an airplane on the ground. GROUND POWER UNIT (GPU)— A type of small gas turbine whose purpose is to provide electrical power, and/or air pressure for starting aircraft engines. Aground unit is connected to the aircraft when needed. Similar to an aircraft-installed auxiliary power unit. GROUNDSPEED (GS)—The actual speed of the airplane over the ground. It is true airspeed adjusted for wind. Groundspeed decreases with a headwind, and increases with a tailwind. which a constant flow of fuel is fed to injection nozzles in the heads of all cylinders just outside of the intake valve. It differs from sequential fuel injection in which a timed charge of high-pressure fuel is sprayed directly into the combustion chamber of the cylinder. FUEL LOAD—The expendable part of the load of the airplane. It includes only usable fuel, not fuel required to fill the lines or that which remains trapped in the tank sumps. FUEL TANK SUMP—A sampling port in the lowest part of the fuel tank that the pilot can utilize to check for contaminants in the fuel. FUSELAGE—The section of the airplane that consists of the cabin and/or cockpit, containing seats for the occupants and the controls for the airplane. GAS GENERATOR—The basic power producing portion of a gas turbine engine and excluding such sections as the inlet duct, the fan section, free power turbines, and tailpipe. Each manufacturer designates what is included as the gas generator, but generally consists of the compressor, diffuser, combustor, and turbine. GAS TURBINE ENGINE—A form of heat engine in which burning fuel adds energy to compressed air and accelerates the air through the remainder of the engine. Some of the energy is extracted to turn the air compressor, and the remainder accelerates the air to produce thrust. Some of this energy can be converted into torque to drive a propeller or a system of rotors for a helicopter. GLIDE RATIO—The ratio between distance traveled and altitude lost during non-powered flight. GLIDEPATH—The path of an aircraft relative to the ground while approaching a landing. GLOBAL POSITION SYSTEM (GPS)—A satellite-based radio positioning, navigation, and time-transfer system. Glossary.qxd 5/7/04 10:46 AM Page G-7 G-8 GROUND TRACK—The aircraft’s path over the ground when in flight. GUST PENETRATION SPEED— The speed that gives the greatest margin between the high and low mach speed buffets. GYROSCOPIC PRECESSION— An inherent quality of rotating bodies, which causes an applied force to be manifested 90º in the direction of rotation from the point where the force is applied. HAND PROPPING—Starting an engine by rotating the propeller by hand. HEADING—The direction in which the nose of the aircraft is pointing during flight. HEADING BUG—A marker on the heading indicator that can be rotated to a specific heading for reference purposes, or to command an autopilot to fly that heading. HEADING INDICATOR— An instrument which senses airplane movement and displays heading based on a 360º azimuth, with the final zero omitted. The heading indicator, also called a directional gyro, is fundamentally a mechanical instrument designed to facilitate the use of the magnetic compass. The heading indicator is not affected by the forces that make the magnetic compass difficult to interpret. HEADWIND COMPONENT—The component of atmospheric winds that acts opposite to the aircraft’s flightpath. HIGH PERFORMANCE AIRCRAFT—An aircraft with an engine of more than 200 horsepower. HORIZON—The line of sight boundary between the earth and the sky. HORSEPOWER— The term, originated by inventor James Watt, means the amount of work a horse could do in one second. engine. Some igniters resemble spark plugs, while others, called glow plugs, have a coil of resistance wire that glows red hot when electrical current flows through the coil. IMPACT ICE—Ice that forms on the wings and control surfaces or on the carburetor heat valve, the walls of the air scoop, or the carburetor units during flight. Impact ice collecting on the metering elements of the carburetor may upset fuel metering or stop carburetor fuel flow. INCLINOMETER—An instrument consisting of a curved glass tube, housing a glass ball, and damped with a fluid similar to kerosene. It may be used to indicate inclination, as a level, or, as used in the turn indicators, to show the relationship between gravity and centrifugal force in a turn. INDICATED AIRSPEED (IAS)— The direct instrument reading obtained from the airspeed indicator, uncorrected for variations in atmospheric density, installation error, or instrument error. Manufacturers use this airspeed as the basis for determining airplane performance. Takeoff, landing, and stall speeds listed in the AFM or POH are indicated airspeeds and do not normally vary with altitude or temperature. INDICATED ALTITUDE— The altitude read directly from the altimeter (uncorrected) when it is set to the current altimeter setting. INDUCED DRAG—That part of total drag which is created by the production of lift. Induced drag increases with a decrease in airspeed. INDUCTION MANIFOLD—The part of the engine that distributes intake air to the cylinders. INERTIA—The opposition which a body offers to a change of motion. INITIAL CLIMB—This stage of the climb begins when the airplane leaves the ground, and a pitch attitude has One horsepower equals 550 foot-pounds per second, or 33,000 foot-pounds per minute. HOT START—In gas turbine engines, a start which occurs with normal engine rotation, but exhaust temperature exceeds prescribed limits. This is usually caused by an excessively rich mixture in the combustor. The fuel to the engine must be terminated immediately to prevent engine damage. HUNG START—In gas turbine engines, a condition of normal light off but with r.p.m. remaining at some low value rather than increasing to the normal idle r.p.m. This is often the result of insufficient power to the engine from the starter. In the event of a hung start, the engine should be shut down. HYDRAULICS—The branch of science that deals with the transmission of power by incompressible fluids under pressure. HYDROPLANING—A condition that exists when landing on a surface with standing water deeper than the tread depth of the tires. When the brakes are applied, there is a possibility that the brake will lock up and the tire will ride on the surface of the water, much like a water ski. When the tires are hydroplaning, directional control and braking action are virtually impossible. An effective anti-skid system can minimize the effects of hydroplaning. HYPOXIA—A lack of sufficient oxygen reaching the body tissues. IFR (INSTRUMENT FLIGHT RULES)—Rules that govern the procedure for conducting flight in weather conditions below VFR weather minimums. The term “IFR” also is used to define weather conditions and the type of flight plan under which an aircraft is operating. IGNITER PLUGS—The electrical device used to provide the spark for starting combustion in a turbine Glossary.qxd 5/7/04 10:46 AM Page G-8 G-9 been established to climb away from the takeoff area. INTEGRAL FUEL TANK— A portion of the aircraft structure, usually a wing, which is sealed off and used as a fuel tank. When a wing is used as an integral fuel tank, it is called a “wet wing.” INTERCOOLER—A device used to reduce the temperature of the compressed air before it enters the fuel metering device. The resulting cooler air has a higher density, which permits the engine to be operated with a higher power setting. INTERNAL COMBUSTION ENGINES—An engine that produces power as a result of expanding hot gases from the combustion of fuel and air within the engine itself. A steam engine where coal is burned to heat up water inside the engine is an example of an external combustion engine. INTERSTAGE TURBINE TEMPERATURE (ITT)—The temperature of the gases between the high pressure and low pressure turbines. INVERTER—An electrical device that changes DC to AC power. ISA (INTERNATIONAL STANDARD ATMOSPHERE)— Standard atmospheric conditions consisting of a temperature of 59°F (15°C), and a barometric pressure of 29.92 in. Hg. (1013.2 mb) at sea level. ISA values can be calculated for various altitudes using a standard lapse rate of approximately 2°C per 1,000 feet. JET POWERED AIRPLANE—An aircraft powered by a turbojet or turbofan engine. KINESTHESIA—The sensing of movements by feel. LATERAL AXIS—An imaginary line passing through the center of gravity of an airplane and extending across the airplane from wingtip to wingtip. the coefficient of drag for any given angle of attack. LIFT-OFF—The act of becoming airborne as a result of the wings lifting the airplane off the ground, or the pilot rotating the nose up, increasing the angle of attack to start a climb. LIMIT LOAD FACTOR—Amount of stress, or load factor, that an aircraft can withstand before structural damage or failure occurs. LOAD FACTOR—The ratio of the load supported by the airplane’s wings to the actual weight of the aircraft and its contents. Also referred to as G-loading. LONGITUDINAL AXIS— An imaginary line through an aircraft from nose to tail, passing through its center of gravity. The longitudinal axis is also called the roll axis of the aircraft. Movement of the ailerons rotates an airplane about its longitudinal axis. LONGITUDINAL STABILITY (PITCHING)—Stability about the lateral axis. A desirable characteristic of an airplane whereby it tends to return to its trimmed angle of attack after displacement. MACH—Speed relative to the speed of sound. Mach 1 is the speed of sound. MACH BUFFET— Airflow separation behind a shock-wave pressure barrier caused by airflow over flight surfaces exceeding the speed of sound. MACH COMPENSATING DEVICE—A device to alert the pilot of inadvertent excursions beyond its certified maximum operating speed. MACH CRITICAL—The MACH speed at which some portion of the airflow over the wing first equals MACH 1.0. This is also the speed at which a shock wave first appears on the airplane. LATERAL STABILITY (ROLLING)—The stability about the longitudinal axis of an aircraft. Rolling stability or the ability of an airplane to return to level flight due to a disturbance that causes one of the wings to drop. LEAD-ACID BATTERY— A commonly used secondary cell having lead as its negative plate and lead peroxide as its positive plate. Sulfuric acid and water serve as the electrolyte. LEADING EDGE DEVICES— High lift devices which are found on the leading edge of the airfoil. The most common types are fixed slots, movable slats, and leading edge flaps. LEADING EDGE—The part of an airfoil that meets the airflow first. LEADING EDGE FLAP— A portion of the leading edge of an airplane wing that folds downward to increase the camber, lift, and drag of the wing. The leading-edge flaps are extended for takeoffs and landings to increase the amount of aerodynamic lift that is produced at any given airspeed. LICENSED EMPTY WEIGHT— The empty weight that consists of the airframe, engine(s), unusable fuel, and undrainable oil plus standard and optional equipment as specified in the equipment list. Some manufacturers used this term prior to GAMA standardization. LIFT—One of the four main forces acting on an aircraft. On a fixed-wing aircraft, an upward force created by the effect of airflow as it passes over and under the wing. LIFT COEFFICIENT— A coefficient representing the lift of a given airfoil. Lift coefficient is obtained by dividing the lift by the free-stream dynamic pressure and the representative area under consideration. LIFT/DRAG RATIO— The efficiency of an airfoil section. It is the ratio of the coefficient of lift to Glossary.qxd 5/7/04 10:46 AM Page G-9 G-10 MACH TUCK—Acondition that can occur when operating a swept-wing airplane in the transonic speed range. A shock wave could form in the root portion of the wing and cause the air behind it to separate. This shock-induced separation causes the center of pressure to move aft. This, combined with the increasing amount of nose down force at higher speeds to maintain left flight, causes the nose to “tuck.” If not corrected, the airplane could enter a steep, sometimes unrecoverable dive. MAGNETIC COMPASS—A device for determining direction measured from magnetic north. MAIN GEAR—The wheels of an aircraft’s landing gear that supports the major part of the aircraft’s weight. MANEUVERABILITY—Ability of an aircraft to change directions along a flightpath and withstand the stresses imposed upon it. MANEUVERING SPEED (VA) — The maximum speed where full, abrupt control movement can be used without overstressing the airframe. MANIFOLD PRESSURE (MP)— The absolute pressure of the fuel/air mixture within the intake manifold, usually indicated in inches of mercury. MAXIMUM ALLOWABLE TAKEOFF POWER—The maximum power an engine is allowed to develop for a limited period of time; usually about one minute. MAXIMUM LANDING WEIGHT—The greatest weight that an airplane normally is allowed to have at landing. MAXIMUM RAMP WEIGHT— The total weight of a loaded aircraft, including all fuel. It is greater than the takeoff weight due to the fuel that will be burned during the taxi and runup operations. Ramp weight may also be referred to as taxi weight. allows air to continue flowing over the top of the wing and delays airflow separation. MUSHING—A flight condition caused by slow speed where the control surfaces are marginally effective. N1, N2, N3—Spool speed expressed in percent rpm. N1 on a turboprop is the gas producer speed. N1 on a turbofan or turbojet engine is the fan speed or low pressure spool speed. N2 is the high pressure spool speed on engine with 2 spools and medium pressure spool on engines with 3 spools with N3 being the high pressure spool. NACELLE— Astreamlined enclosure on an aircraft in which an engine is mounted. On multiengine propeller-driven airplanes, the nacelle is normally mounted on the leading edge of the wing. NEGATIVE STATIC STABILITY—The initial tendency of an aircraft to continue away from the original state of equilibrium after being disturbed. NEGATIVE TORQUE SENSING (NTS)— A system in a turboprop engine that prevents the engine from being driven by the propeller. The NTS increases the blade angle when the propellers try to drive the engine. NEUTRAL STATIC STABILITY—The initial tendency of an aircraft to remain in a new condition after its equilibrium has been disturbed. NICKEL-CADMIUM BATTERY (NICAD)— A battery made up of alkaline secondary cells. The positive plates are nickel hydroxide, the negative plates are cadmium hydroxide, and potassium hydroxide is used as the electrolyte. NORMAL CATEGORY— An airplane that has a seating configuration, excluding pilot seats, MAXIMUM TAKEOFF WEIGHT—The maximum allowable weight for takeoff. MAXIMUM WEIGHT— The maximum authorized weight of the aircraft and all of its equipment as specified in the Type Certificate Data Sheets (TCDS) for the aircraft. MAXIMUM ZERO FUEL WEIGHT (GAMA)—The maximum weight, exclusive of usable fuel. MINIMUM CONTROLLABLE AIRSPEED—An airspeed at which any further increase in angle of attack, increase in load factor, or reduction in power, would result in an immediate stall. MINIMUM DRAG SPEED (L/DMAX)—The point on the total drag curve where the lift-to-drag ratio is the greatest. At this speed, total drag is minimized. MIXTURE—The ratio of fuel to air entering the engine’s cylinders. MMO—Maximum operating speed expressed in terms of a decimal of mach speed. MOMENT ARM—The distance from a datum to the applied force. MOMENT INDEX (OR INDEX)— A moment divided by a constant such as 100, 1,000, or 10,000. The purpose of using a moment index is to simplify weight and balance computations of airplanes where heavy items and long arms result in large, unmanageable numbers. MOMENT—The product of the weight of an item multiplied by its arm. Moments are expressed in pound-inches (lb-in). Total moment is the weight of the airplane multiplied by the distance between the datum and the CG. MOVABLE SLAT—A movable auxiliary airfoil on the leading edge of a wing. It is closed in normal flight but extends at high angles of attack. This Glossary.qxd 5/7/04 10:46 AM Page G-10 G-11 of nine or less, a maximum certificated takeoff weight of 12,500 pounds or less, and intended for nonacrobatic operation. NORMALIZING (TURBONORMALIZING)— A turbocharger that maintains sea level pressure in the induction manifold at altitude. OCTANE—The rating system of aviation gasoline with regard to its antidetonating qualities. OVERBOOST—A condition in which a reciprocating engine has exceeded the maximum manifold pressure allowed by the manufacturer. Can cause damage to engine components. OVERSPEED—A condition in which an engine has produced more r.p.m. than the manufacturer recommends, or a condition in which the actual engine speed is higher than the desired engine speed as set on the propeller control. OVERTEMP—A condition in which a device has reached a temperature above that approved by the manufacturer or any exhaust temperature that exceeds the maximum allowable for a given operating condition or time limit. Can cause internal damage to an engine. OVERTORQUE—A condition in which an engine has produced more torque (power) than the manufacturer recommends, or a condition in a turboprop or turboshaft engine where the engine power has exceeded the maximum allowable for a given operating condition or time limit. Can cause internal damage to an engine. PARASITE DRAG—That part of total drag created by the design or shape of airplane parts. Parasite drag increases with an increase in airspeed. PAYLOAD (GAMA)—The weight of occupants, cargo, and baggage. P-FACTOR—A tendency for an aircraft to yaw to the left due to the for scheduling fuel flow to the combustion chambers of a turbine engine. POWER—Implies work rate or units of work per unit of time, and as such, it is a function of the speed at which the force is developed. The term “power required” is generally associated with reciprocating engines. POWERPLANT— A complete engine and propeller combination with accessories. PRACTICAL SLIP LIMIT—The maximum slip an aircraft is capable of performing due to rudder travel limits. PRECESSION—The tilting or turning of a gyro in response to deflective forces causing slow drifting and erroneous indications in gyroscopic instruments. PREIGNITION—Ignition occurring in the cylinder before the time of normal ignition. Preignition is often caused by a local hot spot in the combustion chamber igniting the fuel/air mixture. PRESSURE ALTITUDE— The altitude indicated when the altimeter setting window (barometric scale) is adjusted to 29.92. This is the altitude above the standard datum plane, which is a theoretical plane where air pressure (corrected to 15ºC) equals 29.92 in. Hg. Pressure altitude is used to compute density altitude, true altitude, true airspeed, and other performance data. PROFILE DRAG—The total of the skin friction drag and form drag for a two-dimensional airfoil section. PROPELLER BLADE ANGLE— The angle between the propeller chord and the propeller plane of rotation. PROPELLER LEVER— The control on a free power turbine turboprop that controls propeller speed and the selection for propeller feathering. PROPELLER SLIPSTREAM— The volume of air accelerated behind a propeller producing thrust. descending propeller blade on the right producing more thrust than the ascending blade on the left. This occurs when the aircraft’s longitudinal axis is in a climbing attitude in relation to the relative wind. The P-factor would be to the right if the aircraft had a counterclockwise rotating propeller. PILOT’S OPERATING HANDBOOK (POH)—A document developed by the airplane manufacturer and contains the FAAapproved Airplane Flight Manual (AFM) information. PISTON ENGINE—A reciprocating engine. PITCH—The rotation of an airplane about its lateral axis, or on a propeller, the blade angle as measured from plane of rotation. PIVOTAL ALTITUDE—A specific altitude at which, when an airplane turns at a given groundspeed, a projecting of the sighting reference line to a selected point on the ground will appear to pivot on that point. PNEUMATIC SYSTEMS— The power system in an aircraft used for operating such items as landing gear, brakes, and wing flaps with compressed air as the operating fluid. PORPOISING— Oscillating around the lateral axis of the aircraft during landing. POSITION LIGHTS—Lights on an aircraft consisting of a red light on the left wing, a green light on the right wing, and a white light on the tail. CFRs require that these lights be displayed in flight from sunset to sunrise. POSITIVE STATIC STABILITY— The initial tendency to return to a state of equilibrium when disturbed from that state. POWER DISTRIBUTION BUS— See BUS BAR. POWER LEVER—The cockpit lever connected to the fuel control unit Glossary.qxd 5/7/04 10:46 AM Page G-11 G-12 PROPELLER SYNCHRONIZATION— A condition in which all of the propellers have their pitch automatically adjusted to maintain a constant r.p.m. among all of the engines of a multiengine aircraft. PROPELLER—A device for propelling an aircraft that, when rotated, produces by its action on the air, a thrust approximately perpendicular to its plane of rotation. It includes the control components normally supplied by its manufacturer. RAMP WEIGHT—The total weight of the aircraft while on the ramp. It differs from takeoff weight by the weight of the fuel that will be consumed in taxiing to the point of takeoff. RATE OF TURN—The rate in degrees/second of a turn. RECIPROCATING ENGINE—An engine that converts the heat energy from burning fuel into the reciprocating movement of the pistons. This movement is converted into a rotary motion by the connecting rods and crankshaft. REDUCTION GEAR—The gear arrangement in an aircraft engine that allows the engine to turn at a faster speed than the propeller. REGION OF REVERSE COMMAND—Flight regime in which flight at a higher airspeed requires a lower power setting and a lower airspeed requires a higher power setting in order to maintain altitude. REGISTRATION CERTIFICATE—A State and Federal certificate that documents aircraft ownership. RELATIVE WIND—The direction of the airflow with respect to the wing. If a wing moves forward horizontally, the relative wind moves backward horizontally. Relative wind is parallel to and opposite the flightpath of the airplane. alignment guidance during takeoff and landings. The centerline consists of a line of uniformly spaced stripes and gaps. RUNWAY EDGE LIGHTS— Runway edge lights are used to outline the edges of runways during periods of darkness or restricted visibility conditions. These light systems are classified according to the intensity or brightness they are capable of producing: they are the High Intensity Runway Lights (HIRL), Medium Intensity Runway Lights (MIRL), and the Low Intensity Runway Lights (LIRL). The HIRL and MIRL systems have variable intensity controls, whereas the LIRLs normally have one intensity setting. RUNWAY END IDENTIFIER LIGHTS (REIL)—One component of the runway lighting system. These lights are installed at many airfields to provide rapid and positive identification of the approach end of a particular runway. RUNWAY INCURSION— Any occurrence at an airport involving an aircraft, vehicle, person, or object on the ground that creates a collision hazard or results in loss of separation with an aircraft taking off, intending to takeoff, landing, or intending to land. RUNWAY THRESHOLD MARKINGS—Runway threshold markings come in two configurations. They either consist of eight longitudinal stripes of uniform dimensions disposed symmetrically about the runway centerline, or the number of stripes is related to the runway width. A threshold marking helps identify the beginning of the runway that is available for landing. In some instances, the landing threshold may be displaced. SAFETY (SQUAT) SWITCH—An electrical switch mounted on one of the landing gear struts. It is used to sense when the weight of the aircraft is on the wheels. SCAN—A procedure used by the pilot to visually identify all resources of information in flight. REVERSE THRUST—A condition where jet thrust is directed forward during landing to increase the rate of deceleration. REVERSING PROPELLER— A propeller system with a pitch change mechanism that includes full reversing capability. When the pilot moves the throttle controls to reverse, the blade angle changes to a pitch angle and produces a reverse thrust, which slows the airplane down during a landing. ROLL—The motion of the aircraft about the longitudinal axis. It is controlled by the ailerons. ROUNDOUT (FLARE)— Apitch-up during landing approach to reduce rate of descent and forward speed prior to touchdown. RUDDER—The movable primary control surface mounted on the trailing edge of the vertical fin of an airplane. Movement of the rudder rotates the airplane about its vertical axis. RUDDERVATOR—Apair of control surfaces on the tail of an aircraft arranged in the form of a V. These surfaces, when moved together by the control wheel, serve as elevators, and when moved differentially by the rudder pedals, serve as a rudder. RUNWAY CENTERLINE LIGHTS—Runway centerline lights are installed on some precision approach runways to facilitate landing under adverse visibility conditions. They are located along the runway centerline and are spaced at 50-foot intervals. When viewed from the landing threshold, the runway centerline lights are white until the last 3,000 feet of the runway. The white lights begin to alternate with red for the next 2,000 feet, and for the last 1,000 feet of the runway, all centerline lights are red. RUNWAY CENTERLINE MARKINGS— The runway centerline identifies the center of the runway and provides Glossary.qxd 5/7/04 10:46 AM Page G-12 G-13 SEA LEVEL—A reference height used to determine standard atmospheric conditions and altitude measurements. SEGMENTED CIRCLE—A visual ground based structure to provide traffic pattern information. SERVICE CEILING— The maximum density altitude where the best rate-of-climb airspeed will produce a 100 feet-per-minute climb at maximum weight while in a clean configuration with maximum continuous power. SERVO TAB—An auxiliary control mounted on a primary control surface, which automatically moves in the direction opposite the primary control to provide an aerodynamic assist in the movement of the control. SHAFT HORSE POWER (SHP)— Turboshaft engines are rated in shaft horsepower and calculated by use of a dynamometer device. Shaft horsepower is exhaust thrust converted to a rotating shaft. SHOCK WAVES—A compression wave formed when a body moves through the air at a speed greater than the speed of sound. SIDESLIP—A slip in which the airplane’s longitudinal axis remains parallel to the original flightpath, but the airplane no longer flies straight ahead. Instead, the horizontal component of wing lift forces the airplane to move sideways toward the low wing. SINGLE ENGINE ABSOLUTE CEILING—The altitude that a twinengine airplane can no longer climb with one engine inoperative. SINGLE ENGINE SERVICE CEILING—The altitude that a twinengine airplane can no longer climb at a rate greater then 50 f.p.m. with one engine inoperative. SKID—A condition where the tail of the airplane follows a path outside the path of the nose during a turn. SPLIT SHAFT TURBINE ENGINE—See FREE POWER TURBINE ENGINE. SPOILERS—High-drag devices that can be raised into the air flowing over an airfoil, reducing lift and increasing drag. Spoilers are used for roll control on some aircraft. Deploying spoilers on both wings at the same time allows the aircraft to descend without gaining speed. Spoilers are also used to shorten the ground roll after landing. SPOOL—A shaft in a turbine engine which drives one or more compressors with the power derived from one or more turbines. STABILATOR—A single-piece horizontal tail surface on an airplane that pivots around a central hinge point. A stabilator serves the purposes of both the horizontal stabilizer and the elevator. STABILITY—The inherent quality of an airplane to correct for conditions that may disturb its equilibrium, and to return or to continue on the original flightpath. It is primarily an airplane design characteristic. STABILIZED APPROACH—A landing approach in which the pilot establishes and maintains a constant angle glidepath towards a predetermined point on the landing runway. It is based on the pilot’s judgment of certain visual cues, and depends on the maintenance of a constant final descent airspeed and configuration. STALL—A rapid decrease in lift caused by the separation of airflow from the wing’s surface brought on by exceeding the critical angle of attack. A stall can occur at any pitch attitude or airspeed. STALL STRIPS—Aspoiler attached to the inboard leading edge of some wings to cause the center section of the wing to stall before the tips. This assures lateral control throughout the stall. SLIP—An intentional maneuver to decrease airspeed or increase rate of descent, and to compensate for a crosswind on landing. A slip can also be unintentional when the pilot fails to maintain the aircraft in coordinated flight. SPECIFIC FUEL CONSUMPTION— Number of pounds of fuel consumed in 1 hour to produce 1 HP. SPEED—The distance traveled in a given time. SPEED BRAKES—A control system that extends from the airplane structure into the airstream to produce drag and slow the airplane. SPEED INSTABILITY— A condition in the region of reverse command where a disturbance that causes the airspeed to decrease causes total drag to increase, which in turn, causes the airspeed to decrease further. SPEED SENSE—The ability to sense instantly and react to any reasonable variation of airspeed. SPIN—An aggravated stall that results in what is termed an “autorotation” wherein the airplane follows a downward corkscrew path. As the airplane rotates around the vertical axis, the rising wing is less stalled than the descending wing creating a rolling, yawing, and pitching motion. SPIRAL INSTABILITY— A condition that exists when the static directional stability of the airplane is very strong as compared to the effect of its dihedral in maintaining lateral equilibrium. SPIRALING SLIPSTREAM—The slipstream of a propeller-driven airplane rotates around the airplane. This slipstream strikes the left side of the vertical fin, causing the airplane to yaw slightly. Vertical stabilizer offset is sometimes used by aircraft designers to counteract this tendency. Glossary.qxd 5/7/04 10:46 AM Page G-13 G-14 STANDARD ATMOSPHERE— At sea level, the standard atmosphere consists of a barometric pressure of 29.92 inches of mercury (in. Hg.) or 1013.2 millibars, and a temperature of 15°C (59°F). Pressure and temperature normally decrease as altitude increases. The standard lapse rate in the lower atmosphere for each 1,000 feet of altitude is approximately 1 in. Hg. and 2°C (3.5°F). For example, the standard pressure and temperature at 3,000 feet mean sea level (MSL) is 26.92 in. Hg. (29.92 - 3) and 9°C (15°C - 6°C). STANDARD DAY— See STANDARD ATMOSPHERE. STANDARD EMPTY WEIGHT (GAMA)—This weight consists of the airframe, engines, and all items of operating equipment that have fixed locations and are permanently installed in the airplane; including fixed ballast, hydraulic fluid, unusable fuel, and full engine oil. STANDARD WEIGHTS—These have been established for numerous items involved in weight and balance computations. These weights should not be used if actual weights are available. STANDARD-RATE TURN—A turn at the rate of 3º per second which enables the airplane to complete a 360º turn in 2 minutes. STARTER/GENERATOR— A combined unit used on turbine engines. The device acts as a starter for rotating the engine, and after running, internal circuits are shifted to convert the device into a generator. STATIC STABILITY—The initial tendency an aircraft displays when disturbed from a state of equilibrium. STATION—A location in the airplane that is identified by a number designating its distance in inches from the datum. The datum is, therefore, identified as station zero. An item located at station +50 would have an arm of 50 inches. TAXIWAY LIGHTS— Omnidirectional lights that outline the edges of the taxiway and are blue in color. TAXIWAY TURNOFF LIGHTS— Flush lights which emit a steady green color. TETRAHEDRON— A large, triangular-shaped, kite-like object installed near the runway. Tetrahedrons are mounted on a pivot and are free to swing with the wind to show the pilot the direction of the wind as an aid in takeoffs and landings. THROTTLE—The valve in a carburetor or fuel control unit that determines the amount of fuel-air mixture that is fed to the engine. THRUST LINE—An imaginary line passing through the center of the propeller hub, perpendicular to the plane of the propeller rotation. THRUST REVERSERS—Devices which redirect the flow of jet exhaust to reverse the direction of thrust. THRUST—The force which imparts a change in the velocity of a mass. This force is measured in pounds but has no element of time or rate. The term, thrust required, is generally associated with jet engines. A forward force which propels the airplane through the air. TIMING—The application of muscular coordination at the proper instant to make flight, and all maneuvers incident thereto, a constant smooth process. TIRE CORD—Woven metal wire laminated into the tire to provide extra strength. A tire showing any cord must be replaced prior to any further flight. TORQUE METER—An indicator used on some large reciprocating engines or on turboprop engines to indicate the amount of torque the engine is producing. STICK PULLER—A device that applies aft pressure on the control column when the airplane is approaching the maximum operating speed. STICK PUSHER—A device that applies an abrupt and large forward force on the control column when the airplane is nearing an angle of attack where a stall could occur. STICK SHAKER—An artificial stall warning device that vibrates the control column. STRESS RISERS— A scratch, groove, rivet hole, forging defect or other structural discontinuity that causes a concentration of stress. SUBSONIC—Speed below the speed of sound. SUPERCHARGER—An engine- or exhaust-driven air compressor used to provide additional pressure to the induction air so the engine can produce additional power. SUPERSONIC—Speed above the speed of sound. SUPPLEMENTAL TYPE CERTIFICATE (STC)— A certificate authorizing an alteration to an airframe, engine, or component that has been granted an Approved Type Certificate. SWEPT WING—A wing planform in which the tips of the wing are farther back than the wing root. TAILWHEEL AIRCRAFT— SEE CONVENTIONAL LANDING GEAR. TAKEOFF ROLL (GROUND ROLL)—The total distance required for an aircraft to become airborne. TARGET REVERSER—A thrust reverser in a jet engine in which clamshell doors swivel from the stowed position at the engine tailpipe to block all of the outflow and redirect some component of the thrust forward. Glossary.qxd 5/7/04 10:46 AM Page G-14 G-15 TORQUE SENSOR— See TORQUE METER. TORQUE—1.Aresistance to turning or twisting. 2. Forces that produce a twisting or rotating motion. 3. In an airplane, the tendency of the aircraft to turn (roll) in the opposite direction of rotation of the engine and propeller. TOTAL DRAG—The sum of the parasite and induced drag. TOUCHDOWN ZONE LIGHTS— Two rows of transverse light bars disposed symmetrically about the runway centerline in the runway touchdown zone. TRACK—The actual path made over the ground in flight. TRAILING EDGE—The portion of the airfoil where the airflow over the upper surface rejoins the lower surface airflow. TRANSITION LINER— The portion of the combustor that directs the gases into the turbine plenum. TRANSONIC—At the speed of sound. TRANSPONDER—The airborne portion of the secondary surveillance radar system. The transponder emits a reply when queried by a radar facility. TRICYCLE GEAR—Landing gear employing a third wheel located on the nose of the aircraft. TRIM TAB—A small auxiliary hinged portion of a movable control surface that can be adjusted during flight to a position resulting in a balance of control forces. TRIPLE SPOOL ENGINE— Usually a turbofan engine design where the fan is the N1 compressor, followed by the N2 intermediate compressor, and the N3 high pressure compressor, all of which rotate on separate shafts at different speeds. TURBINE SECTION—The section of the engine that converts high pressure high temperature gas into rotational energy. TURBOCHARGER— An air compressor driven by exhaust gases, which increases the pressure of the air going into the engine through the carburetor or fuel injection system. TURBOFAN ENGINE—A turbojet engine in which additional propulsive thrust is gained by extending a portion of the compressor or turbine blades outside the inner engine case. The extended blades propel bypass air along the engine axis but between the inner and outer casing. The air is not combusted but does provide additional thrust. TURBOJET ENGINE—A jet engine incorporating a turbine-driven air compressor to take in and compress air for the combustion of fuel, the gases of combustion being used both to rotate the turbine and create a thrust producing jet. TURBOPROP ENGINE—Aturbine engine that drives a propeller through a reduction gearing arrangement. Most of the energy in the exhaust gases is converted into torque, rather than its acceleration being used to propel the aircraft. TURBULENCE—An occurrence in which a flow of fluid is unsteady. TURN COORDINATOR—A rate gyro that senses both roll and yaw due to the gimbal being canted. Has largely replaced the turn-and-slip indicator in modern aircraft. TURN-AND-SLIP INDICATOR— Aflight instrument consisting of a rate gyro to indicate the rate of yaw and a curved glass inclinometer to indicate the relationship between gravity and centrifugal force. The turn-and-slip indicator indicates the relationship between angle of bank and rate of yaw. Also called a turn-and-bank indicator. TROPOPAUSE—The boundary layer between the troposphere and the mesosphere which acts as a lid to confine most of the water vapor, and the associated weather, to the troposphere. TROPOSPHERE—The layer of the atmosphere extending from the surface to a height of 20,000 to 60,000 feet depending on latitude. TRUE AIRSPEED (TAS)— Calibrated airspeed corrected for altitude and nonstandard temperature. Because air density decreases with an increase in altitude, an airplane has to be flown faster at higher altitudes to cause the same pressure difference between pitot impact pressure and static pressure. Therefore, for a given calibrated airspeed, true airspeed increases as altitude increases; or for a given true airspeed, calibrated airspeed decreases as altitude increases. TRUE ALTITUDE—The vertical distance of the airplane above sea level—the actual altitude. It is often expressed as feet above mean sea level (MSL). Airport, terrain, and obstacle elevations on aeronautical charts are true altitudes. T-TAIL—An aircraft with the horizontal stabilizer mounted on the top of the vertical stabilizer, forming a T. TURBINE BLADES—The portion of the turbine assembly that absorbs the energy of the expanding gases and converts it into rotational energy. TURBINE OUTLET TEMPERATURE (TOT)— The temperature of the gases as they exit the turbine section. TURBINE PLENUM—The portion of the combustor where the gases are collected to be evenly distributed to the turbine blades. TURBINE ROTORS—The portion of the turbine assembly that mounts to the shaft and holds the turbine blades in place. Glossary.qxd 5/7/04 10:46 AM Page G-15 G-16 TURNING ERROR—One of the errors inherent in a magnetic compass caused by the dip compensating weight. It shows up only on turns to or from northerly headings in the Northern Hemisphere and southerly headings in the Southern Hemisphere. Turning error causes the compass to lead turns to the north or south and lag turns away from the north or south. ULTIMATE LOAD FACTOR— In stress analysis, the load that causes physical breakdown in an aircraft or aircraft component during a strength test, or the load that according to computations, should cause such a breakdown. UNFEATHERING ACCUMULATOR—Tanks that hold oil under pressure which can be used to unfeather a propeller. UNICOM— A nongovernment air/ground radio communication station which may provide airport information at public use airports where there is no tower or FSS. UNUSABLE FUEL—Fuel that cannot be consumed by the engine. This fuel is considered part of the empty weight of the aircraft. USEFUL LOAD—The weight of the pilot, copilot, passengers, baggage, usable fuel, and drainable oil. It is the basic empty weight subtracted from the maximum allowable gross weight. This term applies to general aviation aircraft only. UTILITY CATEGORY— An airplane that has a seating configuration, excluding pilot seats, of nine or less, a maximum certificated takeoff weight of 12,500 pounds or less, and intended for limited acrobatic operation. V-BARS—The flight director displays on the attitude indicator that provide control guidance to the pilot. V-SPEEDS—Designated speeds for a specific flight condition. VFE—The maximum speed with the flaps extended. The upper limit of the white arc. VFO—The maximum speed that the flaps can be extended or retracted. VFR TERMINAL AREA CHARTS (1:250,000)— Depict Class B airspace which provides for the control or segregation of all the aircraft within the Class B airspace. The chart depicts topographic information and aeronautical information which includes visual and radio aids to navigation, airports, controlled airspace, restricted areas, obstructions, and related data. V-G DIAGRAM—A chart that relates velocity to load factor. It is valid only for a specific weight, configuration, and altitude and shows the maximum amount of positive or negative lift the airplane is capable of generating at a given speed. Also shows the safe load factor limits and the load factor that the aircraft can sustain at various speeds. VISUAL APPROACH SLOPE INDICATOR (VASI)— The most common visual glidepath system in use. The VASI provides obstruction clearance within 10° of the extended runway centerline, and to 4 nautical miles (NM) from the runway threshold. VISUAL FLIGHT RULES (VFR)— Code of Federal Regulations that govern the procedures for conducting flight under visual conditions. VLE—Landing gear extended speed. The maximum speed at which an airplane can be safely flown with the landing gear extended. VLOF—Lift-off speed. The speed at which the aircraft departs the runway during takeoff. VLO—Landing gear operating speed. The maximum speed for extending or retracting the landing gear if using an airplane equipped with retractable landing gear. VAPOR LOCK—A condition in which air enters the fuel system and it may be difficult, or impossible, to restart the engine. Vapor lock may occur as a result of running a fuel tank completely dry, allowing air to enter the fuel system. On fuel-injected engines, the fuel may become so hot it vaporizes in the fuel line, not allowing fuel to reach the cylinders. VA—The design maneuvering speed. This is the “rough air” speed and the maximum speed for abrupt maneuvers. If during flight, rough air or severe turbulence is encountered, reduce the airspeed to maneuvering speed or less to minimize stress on the airplane structure. It is important to consider weight when referencing this speed. For example, VA may be 100 knots when an airplane is heavily loaded, but only 90 knots when the load is light. VECTOR—A force vector is a graphic representation of a force and shows both the magnitude and direction of the force. VELOCITY—The speed or rate of movement in a certain direction. VERTICAL AXIS—An imaginary line passing vertically through the center of gravity of an aircraft. The vertical axis is called the z-axis or the yaw axis. VERTICAL CARD COMPASS— Amagnetic compass that consists of an azimuth on a vertical card, resembling a heading indicator with a fixed miniature airplane to accurately present the heading of the aircraft. The design uses eddy current damping to minimize lead and lag during turns. VERTICAL SPEED INDICATOR (VSI)— An instrument that uses static pressure to display a rate of climb or descent in feet per minute. The VSI can also sometimes be called a vertical velocity indicator (VVI). VERTICAL STABILITY—Stability about an aircraft’s vertical axis. Also called yawing or directional stability. Glossary.qxd 5/7/04 10:46 AM Page G-16 G-17 VMC—Minimum control airspeed. This is the minimum flight speed at which a twin-engine airplane can be satisfactorily controlled when an engine suddenly becomes inoperative and the remaining engine is at takeoff power. VMD—Minimum drag speed. VMO—Maximum operating speed expressed in knots. VNE—Never-exceed speed. Operating above this speed is prohibited since it may result in damage or structural failure. The red line on the airspeed indicator. VNO—Maximum structural cruising speed. Do not exceed this speed except in smooth air. The upper limit of the green arc. VP—Minimum dynamic hydroplaning speed. The minimum speed required to start dynamic hydroplaning. VR—Rotation speed. The speed that the pilot begins rotating the aircraft prior to lift-off. VS0—Stalling speed or the minimum steady flight speed in the landing configuration. In small airplanes, this is the power-off stall speed at the maximum landing weight in the landing configuration (gear and flaps down). The lower limit of the white arc. VS1—Stalling speed or the minimum steady flight speed obtained in a specified configuration. For most airplanes, this is the power-off stall speed at the maximum takeoff weight in the clean configuration (gear up, if retractable, and flaps up). The lower limit of the green arc. VSSE—Safe, intentional one-engine inoperative speed. The minimum speed to intentionally render the critical engine inoperative. V-TAIL—A design which utilizes two slanted tail surfaces to perform equal to the mass of the body times the local value of gravitational acceleration. One of the four main forces acting on an aircraft. Equivalent to the actual weight of the aircraft. It acts downward through the aircraft’s center of gravity toward the center of the Earth. Weight opposes lift. WEIGHT AND BALANCE—The aircraft is said to be in weight and balance when the gross weight of the aircraft is under the max gross weight, and the center of gravity is within limits and will remain in limits for the duration of the flight. WHEELBARROWING— A condition caused when forward yoke or stick pressure during takeoff or landing causes the aircraft to ride on the nosewheel alone. WIND CORRECTION ANGLE— Correction applied to the course to establish a heading so that track will coincide with course. WIND DIRECTION INDICATORS— Indicators that include a wind sock, wind tee, or tetrahedron. Visual reference will determine wind direction and runway in use. WIND SHEAR—A sudden, drastic shift in windspeed, direction, or both that may occur in the horizontal or vertical plane. WINDMILLING—When the air moving through a propeller creates the rotational energy. WINDSOCK—A truncated cloth cone open at both ends and mounted on a freewheeling pivot that indicates the direction from which the wind is blowing. WING—Airfoil attached to each side of the fuselage and are the main lifting surfaces that support the airplane in flight. the same functions as the surfaces of a conventional elevator and rudder configuration. The fixed surfaces act as both horizontal and vertical stabilizers. VX—Best angle-of-climb speed. The airspeed at which an airplane gains the greatest amount of altitude in a given distance. It is used during a short-field takeoff to clear an obstacle. VXSE—Best angle of climb speed with one engine inoperative. The airspeed at which an airplane gains the greatest amount of altitude in a given distance in a light, twin-engine airplane following an engine failure. VY—Best rate-of-climb speed. This airspeed provides the most altitude gain in a given period of time. VYSE—Best rate-of-climb speed with one engine inoperative. This airspeed provides the most altitude gain in a given period of time in a light, twinengine airplane following an engine failure. WAKE TURBULENCE—Wingtip vortices that are created when an airplane generates lift. When an airplane generates lift, air spills over the wingtips from the high pressure areas below the wings to the low pressure areas above them. This flow causes rapidly rotating whirlpools of air called wingtip vortices or wake turbulence. WASTE GATE—A controllable valve in the tailpipe of an aircraft reciprocating engine equipped with a turbocharger. The valve is controlled to vary the amount of exhaust gases forced through the turbocharger turbine. WEATHERVANE—The tendency of the aircraft to turn into the relative wind. WEIGHT—A measure of the heaviness of an object. The force by which a body is attracted toward the center of the Earth (or another celestial body) by gravity. Weight is Glossary.qxd 5/7/04 10:46 AM Page G-17 G-18 WING AREA—The total surface of the wing (square feet), which includes control surfaces and may include wing area covered by the fuselage (main body of the airplane), and engine nacelles. WING SPAN— The maximum distance from wingtip to wingtip. WINGTIP VORTICES— The rapidly rotating air that spills over an airplane’s wings during flight. The intensity of the turbulence depends on the airplane’s weight, speed, and configuration. It is also referred to as ZERO FUEL WEIGHT— The weight of the aircraft to include all useful load except fuel. ZERO SIDESLIP—Amaneuver in a twin-engine airplane with one engine inoperative that involves a small amount of bank and slightly uncoordinated flight to align the fuselage with the direction of travel and minimize drag. ZERO THRUST (SIMULATED FEATHER)— An engine configuration with a low power setting that simulates a propeller feathered condition. wake turbulence. Vortices from heavy aircraft may be extremely hazardous to small aircraft. WING TWIST—A design feature incorporated into some wings to improve aileron control effectiveness at high angles of attack during an approach to a stall. YAW—Rotation about the vertical axis of an aircraft. YAW STRING—Astring on the nose or windshield of an aircraft in view of the pilot that indicates any slipping or skidding of the aircraft. Glossary.qxd 5/7/04 10:46 AM Page G-18 I-1 180° POWER-OFF APPROACH 8-23 360° POWER-OFF APPROACH 8-24 90° POWER-OFF APPROACH 8-21 A ABSOLUTE CEILING 12-8 ACCELERATED STALL 4-9 ACCELERATE-GO DISTANCE 12-8 ACCELERATE-STOP DISTANCE 12-8 ACCURACYAPPROACH 8-21 180° power-off 8-23 360° power-off 8-24 90° power-off 8-21 ADVERSE YAW3-8 AFTER LANDING 2-11 crosswind tailwheel 13-5 roll 8-7 tailwheel 13-4 AIMING POINT 8-8 AIRCRAFT LOGBOOKS 2-1 AIRFOIL TYPES 11-1 AIRMANSHIP 1-1 skills 1-1 AIRPLANE EQUIPMENT, Night 10-3 AIRPLANE FEEL 3-2 AIRPLANE LIGHTING, Night 10-3 AIRPORT LIGHTING 10-4 AIRPORT TRAFFIC PATTERN 7-1 base leg 7-3 crosswind leg 7-4 departure leg 7-4 downwind leg 7-3 entry leg 7-3 final approach leg 7-3 upwind leg 7-3 AIRWORTHINESS DIRECTIVES 2-1 ALTERNATOR/GENERATOR 12-7 ALTITUDE TURBOCHARGING 11-7 ANTI-ICING 12-7 APPROACH AND LANDING 8-1 after-landing roll 8-7 base leg 8-1 crosswind 8-15 emergency 8-25 estimating height and movement 8-4 faulty 8-27 final approach 8-2 go-around 8-11 multiengine 12-14 night 10-6 normal 8-1 roundout (flare) 8-5 short-field 8-17 soft-field 8-19 stabilized approach 8-7 touchdown 8-6 turbulent air 8-17 use of flaps 8-3 ATTITUDE FLYING 3-2 AUTOPILOT 12-6 AXIAL FLOW 14-5 B BACK SIDE OF THE POWER CURVE 8-19 BALLOONING 8-3, 8-30 BANK ATTITUDE 3-2 BASE LEG 7-3, 8-1 BEFORE TAKEOFF CHECK 2-11 BEST ANGLE OF CLIMB (VX) 3-13, 12-1 one engine inoperative (VXSE) 12-1 BEST GLIDE SPEED 3-16 BEST RATE OF CLIMB 3-13, 12-1 one engine inoperative (VYSE) 12-1 BETA RANGE 14-7 BLACK HOLE APPROACH 10-2 BOUNCING 8-30 BUS BAR 14-8 BUS TIE 14-9 BYPASS AIR 15-2 BYPASS RATIO 15-2 C CASCADE REVERSER 15-14 CENTRIFUGAL COMPRESSOR STAGE 14-5 CHANDELLE 9-4 CHECKLISTS, Use of, 1-6 CIRCUIT BREAKER 14-9 CLEAR OF RUNWAY 2-11 CLIMB GRADIENT 12-8 Index.qxd 5/7/04 10:52 AM Page I-1 I-2 CLIMBS 3-13 maximum performance 5-8 night 10-5 COCKPIT MANAGEMENT 2-7 COLLISION AVOIDANCE 1-4 COMBUSTION CHAMBER 14-1 COMBUSTION HEATER 12-6 COMPLEX AIRPLANE 11-1 COMPRESSION RATIO 15-1 COMPRESSOR 14-1 CONDITION LEVER 14-4 CONES 10-1 CONFINED AREA 16-4 CONSTANT-SPEED PROPELLER 11-4 blade angle control 11-5 governing range 11-5 operation 11-5 CONTROLLABLE-PITCH PROPELLER 11-3 CONVENTIONAL GEAR AIRPLANE 13-1 CORE AIRFLOW 15-2 CRAZING 2-2 CRITICALALTITUDE 11-7 CRITICAL MACH 15-7 CROSS-CONTROL STALL 4-10 CROSSWIND APPROACH AND LANDING 8-13 CROSSWIND COMPONENT 5-6 CROSSWIND LEG 7-4 CROSSWIND TAKEOFF 5-5 CURRENT LIMITER 14-9 D DEICING 12-7 DEPARTURE LEG 7-4 DESCENTS 3-15 minimum safe airspeed 3-16 partial power 3-16 DITCHING 16-1 DOWNWASH 8-3 DOWNWIND LEG 7-3 DRAG DEVICES 15-13 DRIFT 6-2 DUCTED FAN 15-2 E EGT 11-8 EIGHTS ACROSS A ROAD 6-11 EIGHTS ALONG A ROAD 6-9 EIGHTS AROUND PYLONS 6-11 EIGHTS-ON-PYLONS 6-12 ELEMENTARY EIGHTS 6-9 ELEVATOR TRIM STALL 4-11 ELT 2-1 EMERGENCIES abnormal instrument indications 16-11 door open in flight 16-12 electrical system 16-10 engine failure 16-5 fires 16-7 flap failure 16-8 landing gear malfunction 16-9 loss of elevator control 16-9 night 10-8 pitot-static system 16-11 VFR flight into IMC 16-12 EMERGENCYAPPROACH AND LANDING 8-25 EMERGENCY DESCENTS 16-6 EMERGENCY GEAR EXTENSION SYSTEM 11-10 EMERGENCY LANDINGS 16-1 airplane configuration 16-3 psychological hazards 16-1 safety concepts 16-2 terrain selection 16-3 terrain types 16-4 EMERGENCY LOCATOR TRANSMITTER 2-1 ENGINE FAILURE AFTER TAKEOFF 16-5 ENGINE FAILURE, MULTIENGINE approach and landing 12-22 during flight 12-21 flight principles 12-23 takeoff 12-18 ENGINE SHUTDOWN 2-12 ENGINE STARTING 2-7 ENTRY LEG 7-3 EXHAUST GAS TEMPERATURE 11-8 EXHAUST MANIFOLD 11-7 EXHAUST SECTION 14-1 F FALSE START 14-10 FAULTYAPPROACHES 8-27 ballooning 8-30 floating 8-29 high final 8-27 high roundout 8-28 low final 8-27 slow final 8-28 FEATHERING 12-3 FEDERALAVIATION ADMINISTRATION (FAA) 1-1 FEEL OF THE AIRPLANE 3-2 FINAL APPROACH 8-2 FINAL APPROACH LEG 7-3 FIRES cabin 16-8 electrical 16-7 engine 16-7 Index.qxd 5/7/04 10:52 AM Page I-2 I-3 FIXED SHAFT ENGINE 14-3 FLAP EXTENSION SPEED (VFE) 12-15 FLAPS 11-1 effectiveness 11-2 function 11-1 operational procedures 11-2 use of 8-3 FLARE 8-5 FLIGHT CONTROLS 3-1 FLIGHT DIRECTOR 12-6 FLIGHT IDLE 14-7 FLIGHT INSTRUCTOR, ROLE OF 1-3 FLIGHT SAFETY 1-4 FLIGHT STANDARDS DISTRICT OFFICE (FSDO) 1-2 FLIGHT TRAINING SCHOOLS 1-3 FLOATING 8-29 FORCED LANDING 16-1 FORWARD SLIP 8-10 FOUR FUNDAMENTALS 3-1 FREE TURBINE ENGINE 14-5 FUEL CONTROL UNIT 14-6 FUEL CONTROLLER 14-1 FUEL CROSSFEED 12-5 FUEL HEATER 15-3 G GAS GENERATOR 15-2 GAS TURBINE ENGINE 14-1 GLIDE 3-16 GLIDE RATIO 3-16 GO-AROUND (REJECTED LANDING) 8-11, 12-17 GOVERNING RANGE 11-5 GROUND BOOSTING 11-7 GROUND EFFECT 5-7, 8-13 GROUND INSPECTION 2-1 GROUND LOOP 8-33, 13-6 GROUND OPERATIONS 2-7 GROUND REFERENCE MANEUVERS 6-1 drift and ground track control 6-2 eights across a road 6-11 eights along a road 6-9 eights around pylons 6-11 eights-on-pylons (pylon eights) 6-12 rectangular course 6-4 s-turns across a road 6-6 turns around a point 6-7 GROUND ROLL 5-1 GROUND TRACK CONTROL 6-2 GROUNDSPEED 6-3 HAND PROPPING 2-8 HAND SIGNALS 2-7 HIGH PERFORMANCE AIRPLANE 11-1 HOT START 14-10 HUNG START 14-10 HYDROPLANING 8-34 I ILLUSIONS 10-2 INITIAL CLIMB 5-1 INTAKE MANIFOLD 11-7 INTEGRATED FLIGHT INSTRUCTION 3-3 INTENTIONAL SPIN 4-15 INVERTER 14-8 JET AIRPLANE 15-1 approach and landing 15-19 low speed flight 15-10 pilot sensations 15-15 rotation and lift-off 15-18 stalls 15-10 takeoff and climb 15-16 touchdown and rollout 15-24 J JET ENGINE 15-1 efficiency 15-5 fuel heater 15-3 ignition 15-3 operating 15-2 K KINESTHESIA 3-2 L L/DMAX 3-16 LANDING GEAR controls 11-10 electrical 11-9 electrohydraulic 11-9 emergency extension 11-10 hydraulic 11-9 malfunction 16-9 operational procedures 11-12 position indicators 11-10 retractable 11-9 safety devices 11-10 tailwheel 13-1 LATERALAXIS 3-2 LAZY EIGHT 9-6 LEVEL FLIGHT 3-4 LIFT-OFF 5-1 LIFT-OFF SPEED (VLOF) 12-1 Index.qxd 5/7/04 10:52 AM Page I-3 I-4 LONGITUDINAL AXIS 3-2 LOSS OF DIRECTIONAL CONTROL DEMONSTRATION 12-27 M MACH 15-7 MACH BUFFET BOUNDARIES 15-8 MACH TUCK 15-7 MANEUVERING SPEED 9-1 MAXIMUM OPERATING SPEED 15-6 MAXIMUM PERFORMANCE CLIMB 5-8 MAXIMUM SAFE CROSSWIND VELOCITIES 8-16 MINIMUM CONTROL SPEED (VMC) 12-2 MINIMUM CONTROLLABLE AIRSPEED 4-1 MINIMUM DRAG SPEED 4-2 MULTIENGINE AIRPLANE 12-1 approach and landing 12-14 crosswind approach and landing 12-16 engine failure during flight 12-21 engine failure on takeoff 12-18 fuel crossfeed 12-5 go-around 12-17 ground operation 12-12 level off and cruise 12-14 one engine inoperative approach and landing 12-22 propeller 12-3 propeller synchronization 12-5 rejected takeoff 12-18 short-field operations 12-16 slow flight 12-25 stalls 12-25 takeoff and climb 12-12 weight and balance 12-10 MUSHING 3-2 N NIGHT OPERATIONS airplane equipment 10-3 airplane lighting 10-3 airport and navigation lighting aids 10-4 approach and landing 10-6 emergencies 10-8 illusions 10-2 orientation and navigation 10-6 pilot equipment 10-3 preparation and preflight 10-4 start, taxi, and runup 10-5 takeoff and climb 10-5 NIGHT VISION 10-1 NOISE ABATEMENT 5-11 NORMAL TAKEOFF 5-2 NOSE BAGGAGE COMPARTMENT 12-7 O ONE-ENGINE-INOPERATIVE SPEED (VSSE) 12-1 OVERBANKING TENDENCY 3-9 OVERBOOST CONDITION 11-9 OVERSPEED 15-8 P PARALLAX ERROR 3-11 PARKING 2-11 PILOT EQUIPMENT, Night 10-3 PILOT EXAMINER, Role of 1-2 PITCH AND POWER 3-19 PITCH ATTITUDE 3-2 PIVOTALALTITUDE 6-14 PORPOISING 8-31 POSITION LIGHTS 10-3 POSITIVE TRANSFER OF CONTROLS 1-6 POSTFLIGHT 2-12 POWER CURVE 8-19 POWER LEVER 14-4 PRACTICAL SLIP LIMIT 8-11 PRACTICAL TEST STANDARDS (PTS) 1-4 PRECAUTIONARY LANDING 16-1 PREFLIGHT INSPECTION 2-2 PRESSURE CONTROLLER 11-7 PROPELLER 11-3, 12-3 PROPELLER BLADE ANGLE 11-4 control 11-5 PROPELLER CONTROL 11-4 PROPELLER SYNCHRONIZATION 12-5 PSYCHOLOGICAL HAZARDS 16-1 PYLON EIGHTS 6-12 R RADIUS OF TURN 3-10 RECTANGULAR COURSE 6-4 REGION OF REVERSE COMMAND 8-19 REJECTED LANDING 8-11 REJECTED TAKEOFF 5-11, 12-18 RETRACTABLE LANDING GEAR 11-9 approach and landing 11-13 controls 11-10 electrical 11-9 electrohydraulic 11-9 emergency extension 11-10 hydraulic 11-9 Index.qxd 5/7/04 10:52 AM Page I-4 I-5 operational procedures 11-12 position indicators 11-10 safety devices 11-10 takeoff and climb 11-13 transition training 11-14 REVERSE THRUST 14-7 RODS 10-1 ROTATING BEACON 10-4 ROTATION 5-1 ROTATION SPEED (VR) 12-1 ROUGH-FIELD TAKEOFF 5-10 ROUNDOUT 8-5 ballooning 8-3 floating 8-29 high 8-28 late or rapid 8-29 RUNWAY INCURSION 1-5 RUNWAY LIGHTS 10-4 S SAFETY CONCEPTS 16-2 SECONDARY STALL 4-9 SECURING 2-12 SEGMENTED CIRCLE 7-3 SERVICE CEILING 12-8 SERVICING 2-12 SHORT-FIELD approach and landing 8-17 tailwheel 13-3 takeoff 5-8 SIDESLIP 5-6, 8-10 SINK RATE 16-3 SKID 3-8 SLIP 3-8, 8-10 SLOW FLIGHT 4-1, 12-25 SOFT FIELD approach and landing 8-19 tailwheel 13-4 takeoff 5-10 SPEED BRAKE 15-13 SPEED INSTABILITY 4-2 SPIN AWARENESS 12-26 SPINS 4-12 developed phase 4-14 entry phase 4-13 incipient phase 4-13 intentional 4-15 procedures 4-13 recovery phase 4-14 weight and balance requirements 4-16 SPLIT SHAFT ENGINE 14-5 SPOILERS 15-13 SQUAT SWITCH 11-10 STABILIZED APPROACH 8-7, 15-21 STALLAWARENESS 1-6 STALLS 4-3 accelerated 4-9 characteristics 4-6 cross-control 4-10 elevator trim 4-11 imminent 4-6 jet airplane 15-10 multiengine 12-25 power-off 4-7 power-on 4-8 recognition 4-3 recovery 4-4 secondary 4-9 use of ailerons/rudders 4-5 STEEP SPIRAL 9-3 STEEP TURNS 9-1 STRAIGHT FLIGHT 3-5 STRAIGHT-AND-LEVEL FLIGHT 3-4 S-TURNS ACROSS A ROAD 6-6 T TAILWHEELAIRPLANES 13-1 crosswind landing 13-5 crosswind takeoff 13-3 short-field landing 13-6 short-field takeoff 13-3 soft-field landing 13-6 soft-field takeoff 13-4 takeoff 13-3 takeoff roll 13-2 taxiing 13-1 touchdown 13-4 wheel landing 13-6 TAKEOFF crosswind 5-5 ground effect 5-7 multiengine 12-2 night 10-5 normal 5-2 rejected 5-11 roll 5-1 short field 5-8 soft/rough field 5-10 tailwheel 13-3 tailwheel crosswind 13-3 tailwheel short-field 13-3 tailwheel soft-field 13-4 TARGET REVERSER 15-14 TAXIING 2-9 tailwheel 13-1 THRUST LEVER 15-4 THRUST REVERSERS 15-14 TOUCHDOWN 8-6 bounce 8-30 crab 8-32 drift 8-32 Index.qxd 5/7/04 10:52 AM Page I-5 I-6 ground loop 8-33 hard landing 8-32 porpoise 8-31 tailwheel 13-4 wheelbarrowing 8-32 wing rise 8-33 TRACK 6-2 TRAFFIC PATTERN INDICATOR 7-3 TRANSITION TRAINING complex airplane 11-14 high performance airplane 11-14 jet powered airplanes 15-1 multiengine airplane 12-31 tailwheel airplanes 13-1 turbopropeller powered airplanes 14-12 TRANSONIC FLOW 15-7 TRIM CONTROL 3-6 TURBINE INLET TEMPERATURE 11-8 TURBINE SECTION 14-1 TURBOCHARGER 11-7 failure 11-9 heat management 11-8 operating characteristics 11-8 TURBOFAN ENGINE 15-2 TURBOPROPAIRPLANE 14-1 electrical system 14-8 operational considerations 14-10 TURBOPROP ENGINES 14-2 TURBULENT AIR APPROACH AND LANDING 8-17 TURNS 3-7 climbing 3-15 coordinated 3-9 gliding 3-18 level 3-7 medium 3-7 shallow 3-7 steep 3-8 TURNS AROUND A POINT 6-7 U UPWIND LEG 7-3 V VFR FLIGHT INTO IMC CONDITIONS 16-12 VISUAL GROUND INSPECTION 2-1 V-SPEEDS 12-1, 15-16, 15-19 W WASTE GATE 11-7 WEATHERVANE 5-5 WEIGHT AND BALANCE 12-10 WHEEL LANDING 13-6 WHEELBARROWING 5-9, 8-17, 8-32 WINDSOCK 7-3 WINGTIPWASHOUT 4-5 Y YAW 3-2 YAW DAMPER 12-6 Index.qxd 5/7/04 10:52 AM Page I-6