7-3-7. Helicopters
In a slow hover taxi or stationary hover near the
surface, helicopter main rotor(s) generate downwash
producing high velocity outwash vortices to a
distance approximately three times the diameter of
the rotor. When rotor downwash hits the surface, the
resulting outwash vortices have behavioral character-
istics similar to wing tip vortices produced by fixed
wing aircraft. However, the vortex circulation is
outward, upward, around, and away from the main
rotor(s) in all directions. Pilots of small aircraft
should avoid operating within three rotor diameters
of any helicopter in a slow hover taxi or stationary
hover. In forward flight, departing or landing
helicopters produce a pair of strong, high-speed
trailing vortices similar to wing tip vortices of larger
fixed wing aircraft. Pilots of small aircraft should use
caution when operating behind or crossing behind
landing and departing helicopters.
7-3-8. Pilot Responsibility
a. Government and industry groups are making
concerted efforts to minimize or eliminate the
hazards of trailing vortices. However, the flight
disciplines necessary to ensure vortex avoidance
during VFR operations must be exercised by the pilot.
Vortex visualization and avoidance procedures
should be exercised by the pilot using the same degree
of concern as in collision avoidance.
b. Wake turbulence may be encountered by
aircraft in flight as well as when operating on the
airport movement area.
REFERENCE-
Pilot/Controller Glossary Term- Wake Turbulence.
c. Pilots are reminded that in operations conducted
behind all aircraft, acceptance of instructions from
ATC in the following situations is an acknowledg-
ment that the pilot will ensure safe takeoff and
landing intervals and accepts the responsibility for
providing wake turbulence separation.
1. Traffic information.
2. Instructions to follow an aircraft; and
3. The acceptance of a visual approach
clearance.
d. For operations conducted behind heavy air-
craft, ATC will specify the word “heavy” when this
information is known. Pilots of heavy aircraft should
always use the word “heavy” in radio communica-
tions.
e. Heavy and large jet aircraft operators should use
the following procedures during an approach to
landing. These procedures establish a dependable
baseline from which pilots of in-trail, lighter aircraft
may reasonably expect to make effective flight path
adjustments to avoid serious wake vortex turbulence.
1. Pilots of aircraft that produce strong wake
vortices should make every attempt to fly on the
established glidepath, not above it; or, if glidepath
guidance is not available, to fly as closely as possible
to a “3-1” glidepath, not above it.
EXAMPLE-
Fly 3,000 feet at 10 miles from touchdown, 1,500 feet at 5
miles, 1,200 feet at 4 miles, and so on to touchdown.
AIM 2/14/08
7-3-7
Wake Turbulence
2. Pilots of aircraft that produce strong wake
vortices should fly as closely as possible to the
approach course centerline or to the extended
centerline of the runway of intended landing as
appropriate to conditions.
f. Pilots operating lighter aircraft on visual
approaches in-trail to aircraft producing strong wake
vortices should use the following procedures to assist
in avoiding wake turbulence. These procedures apply
only to those aircraft that are on visual approaches.
1. Pilots of lighter aircraft should fly on or
above_the glidepath. Glidepath reference may be
furnished by an ILS, by a visual approach slope
system, by other ground-based approach slope
guidance systems, or by other means. In the absence
of visible glidepath guidance, pilots may very nearly
duplicate a 3-degree glideslope by adhering to the
“3_to 1” glidepath principle.
EXAMPLE-
Fly 3,000 feet at 10 miles from touchdown, 1,500 feet at
5_miles, 1,200 feet at 4 miles, and so on to touchdown.
2. If the pilot of the lighter following aircraft has
visual contact with the preceding heavier aircraft and
also with the runway, the pilot may further adjust for
possible wake vortex turbulence by the following
practices:
(a) Pick a point of landing no less than
1,000_feet from the arrival end of the runway.
(b) Establish a line-of-sight to that landing
point that is above and in front of the heavier
preceding aircraft.
(c) When possible, note the point of landing
of the heavier preceding aircraft and adjust point of
intended landing as necessary.
EXAMPLE-
A puff of smoke may appear at the 1,000-foot markings of
the runway, showing that touchdown was that point;
therefore, adjust point of intended landing to the
1,500-foot markings.
(d) Maintain the line-of-sight to the point of
intended landing above and ahead of the heavier
preceding aircraft; maintain it to touchdown.
(e) Land beyond the point of landing of the
preceding heavier aircraft.
3. During visual approaches pilots may ask ATC
for updates on separation and groundspeed with
respect to heavier preceding aircraft, especially when
there is any question of safe separation from wake
turbulence.
7-3-9. Air Traffic Wake Turbulence
Separations
a. Because of the possible effects of wake
turbulence, controllers are required to apply no less
than specified minimum separation for aircraft
operating behind a heavy jet and, in certain instances,
behind large nonheavy aircraft (i.e., B757 aircraft).
1. Separation is applied to aircraft operating
directly behind a heavy/B757 jet at the same altitude
or less than 1,000 feet below:
(a) Heavy jet behind heavy jet-4 miles.
(b) Large/heavy behind B757 - 4 miles.
(c) Small behind B757 - 5 miles.
(d) Small/large aircraft behind heavy jet -
5_miles.
2. Also, separation, measured at the time the
preceding aircraft is over the landing threshold, is
provided to small aircraft:
(a) Small aircraft landing behind heavy jet -
6 miles.
(b) Small aircraft landing behind B757 -
5 miles.
(c) Small aircraft landing behind large
aircraft- 4 miles.
REFERENCE-
Pilot/Controller Glossary Term- Aircraft Classes.
3. Additionally, appropriate time or distance
intervals are provided to departing aircraft:
(a) Two minutes or the appropriate 4 or 5 mile
radar separation when takeoff behind a heavy/B757
jet will be:
(1) From the same threshold.
(2) On a crossing runway and projected
flight paths will cross.
(3) From the threshold of a parallel runway
when staggered ahead of that of the adjacent runway
by less than 500 feet and when the runways are
separated by less than 2,500 feet.
NOTE-
Controllers may not reduce or waive these intervals.
AIM 2/14/08
7-3-8 Wake Turbulence
b. A 3-minute interval will be provided when a
small aircraft will takeoff:
1. From an intersection on the same runway
(same or opposite direction) behind a departing large
aircraft,
2. In the opposite direction on the same runway
behind a large aircraft takeoff or low/missed
approach.
NOTE-
This 3-minute interval may be waived upon specific pilot
request.
c. A 3-minute interval will be provided for all
aircraft taking off when the operations are as
described in subparagraph b1 and 2 above, the
preceding aircraft is a heavy/B757 jet, and the
operations are on either the same runway or parallel
runways separated by less than 2,500 feet.
Controllers may not reduce or waive this interval.
d. Pilots may request additional separation i.e.,
2_minutes instead of 4 or 5 miles for wake turbulence
avoidance. This request should be made as soon as
practical on ground control and at least before taxiing
onto the runway.
NOTE14 CFR Section 91.3(a) states: “The pilot-in-command of
an aircraft is directly responsible for and is the final
authority as to the operation of that aircraft.”
e. Controllers may anticipate separation and need
not withhold a takeoff clearance for an aircraft
departing behind a large/heavy aircraft if there is
reasonable assurance the required separation will
exist when the departing aircraft starts takeoff roll.
AIM 2/14/08
7-4-1
Bird Hazards and Flight Over National Refuges, Parks, and Forests
Section 4. Bird Hazards and Flight Over National
Refuges, Parks, and Forests
7-4-1. Migratory Bird Activity
a. Bird strike risk increases because of bird
migration during the months of March through April,
and August through November.
b. The altitudes of migrating birds vary with winds
aloft, weather fronts, terrain elevations, cloud
conditions, and other environmental variables. While
over 90 percent of the reported bird strikes occur at or
below 3,000 feet AGL, strikes at higher altitudes are
common during migration. Ducks and geese are
frequently observed up to 7,000 feet AGL and pilots
are cautioned to minimize en route flying at lower
altitudes during migration.
c. Considered the greatest potential hazard to
aircraft because of their size, abundance, or habit of
flying in dense flocks are gulls, waterfowl, vultures,
hawks, owls, egrets, blackbirds, and starlings.
Four_major migratory flyways exist in the U.S. The
Atlantic flyway parallels the Atlantic Coast. The
Mississippi Flyway stretches from Canada through
the Great Lakes and follows the Mississippi River.
The Central Flyway represents a broad area east of the
Rockies, stretching from Canada through Central
America. The Pacific Flyway follows the west coast
and overflies major parts of Washington, Oregon, and
California. There are also numerous smaller flyways
which cross these major north-south migratory
routes.
7-4-2. Reducing Bird Strike Risks
a. The most serious strikes are those involving
ingestion into an engine (turboprops and turbine jet
engines) or windshield strikes. These strikes can
result in emergency situations requiring prompt
action by the pilot.
b. Engine ingestions may result in sudden loss of
power or engine failure. Review engine out
procedures, especially when operating from airports
with known bird hazards or when operating near high
bird concentrations.
c. Windshield strikes have resulted in pilots
experiencing confusion, disorientation, loss of
communications, and aircraft control problems.
Pilots are encouraged to review their emergency
procedures before flying in these areas.
d. When encountering birds en route, climb to
avoid collision, because birds in flocks generally
distribute themselves downward, with lead birds
being at the highest altitude.
e. Avoid overflight of known areas of bird
concentration and flying at low altitudes during bird
migration. Charted wildlife refuges and other natural
areas contain unusually high local concentration of
birds which may create a hazard to aircraft.
7-4-3. Reporting Bird Strikes
Pilots are urged to report any bird or other wildlife
strike using FAA Form 5200-7, Bird/Other Wildlife
Strike Report (Appendix 1). Additional forms are
available at any FSS; at any FAA Regional Office or
at http://wildlife-mitigation.tc.faa.gov. The data
derived from these reports are used to develop
standards to cope with this potential hazard to aircraft
and for documentation of necessary habitat control on
airports.
7-4-4. Reporting Bird and Other Wildlife
Activities
If you observe birds or other animals on or near the
runway, request airport management to disperse the
wildlife before taking off. Also contact the nearest
FAA ARTCC, FSS, or tower (including non-Federal
towers) regarding large flocks of birds and report the:
a. Geographic location.
b. Bird type (geese, ducks, gulls, etc.).
c. Approximate numbers.
d. Altitude.
e. Direction of bird flight path.
AIM 2/14/08
7-4-2 Bird Hazards and Flight Over National Refuges, Parks, and Forests
7-4-5. Pilot Advisories on Bird and Other
Wildlife Hazards
Many airports advise pilots of other wildlife hazards
caused by large animals on the runway through the
A/FD and the NOTAM system. Collisions of landing
and departing aircraft and animals on the runway are
increasing and are not limited to rural airports. These
accidents have also occurred at several major
airports. Pilots should exercise extreme caution when
warned of the presence of wildlife on and in the
vicinity of airports. If you observe deer or other large
animals in close proximity to movement areas, advise
the FSS, tower, or airport management.
7-4-6. Flights Over Charted U.S. Wildlife
Refuges, Parks, and Forest Service Areas
a. The landing of aircraft is prohibited on lands or
waters administered by the National Park Service,
U.S. Fish and Wildlife Service, or U.S. Forest Service
without authorization from the respective agency.
Exceptions include:
1. When forced to land due to an emergency
beyond the control of the operator;
2. At officially designated landing sites; or
3. An approved official business of the Federal
Government.
b. Pilots are requested to maintain a minimum
altitude of 2,000 feet above the surface of the
following: National Parks, Monuments, Seashores,
Lakeshores, Recreation Areas and Scenic Riverways
administered by the National Park Service, National
Wildlife Refuges, Big Game Refuges, Game Ranges
and Wildlife Ranges administered by the U.S. Fish
and Wildlife Service, and Wilderness and Primitive
areas administered by the U.S. Forest Service.
NOTE-
FAA Advisory Circular AC 91-36, Visual Flight
Rules_(VFR) Flight Near Noise-Sensitive Areas, defines
the surface of a national park area (including parks,
forests, primitive areas, wilderness areas, recreational
areas, national seashores, national monuments, national
lakeshores, and national wildlife refuge and range areas)
as: the highest terrain within 2,000 feet laterally of the
route of flight, or the upper-most rim of a canyon or valley.
c. Federal statutes prohibit certain types of flight
activity and/or provide altitude restrictions over
designated U.S. Wildlife Refuges, Parks, and Forest
Service Areas. These designated areas, for example:
Boundary Waters Canoe Wilderness Areas,
Minnesota; Haleakala National Park, Hawaii;
Yosemite National Park, California; and Grand
Canyon National Park, Arizona, are charted on
Sectional Charts.
d. Federal regulations also prohibit airdrops by
parachute or other means of persons, cargo, or objects
from aircraft on lands administered by the three
agencies without authorization from the respective
agency. Exceptions include:
1. Emergencies involving the safety of human
life; or
2. Threat of serious property loss.
AIM 2/14/08
7-5-1
Potential Flight Hazards
Section 5. Potential Flight Hazards
7-5-1. Accident Cause Factors
a. The 10 most frequent cause factors for general
aviation accidents that involve the pilot-in-command
are:
1. Inadequate preflight preparation and/or
planning.
2. Failure to obtain and/or maintain flying
speed.
3. Failure to maintain direction control.
4. Improper level off.
5. Failure to see and avoid objects or
obstructions.
6. Mismanagement of fuel.
7. Improper inflight decisions or planning.
8. Misjudgment of distance and speed.
9. Selection of unsuitable terrain.
10. Improper operation of flight controls.
b. This list remains relatively stable and points out
the need for continued refresher training to establish
a higher level of flight proficiency for all pilots. A
part of the FAA's continuing effort to promote
increased aviation safety is the Aviation Safety
Program. For information on Aviation Safety
Program activities contact your nearest Flight
Standards District Office.
c. Alertness. Be alert at all times, especially
when the weather is good. Most pilots pay attention
to business when they are operating in full IFR
weather conditions, but strangely, air collisions
almost invariably have occurred under ideal weather
conditions. Unlimited visibility appears to encourage
a sense of security which is not at all justified.
Considerable information of value may be obtained
by listening to advisories being issued in the terminal
area, even though controller workload may prevent a
pilot from obtaining individual service.
d. Giving Way. If you think another aircraft is too
close to you, give way instead of waiting for the other
pilot to respect the right-of-way to which you may be
entitled. It is a lot safer to pursue the right-of-way
angle after you have completed your flight.
7-5-2. VFR in Congested Areas
A high percentage of near midair collisions occur
below 8,000 feet AGL and within 30 miles of an
airport. When operating VFR in these highly
congested areas, whether you intend to land at an
airport within the area or are just flying through, it is
recommended that extra vigilance be maintained and
that you monitor an appropriate control frequency.
Normally the appropriate frequency is an approach
control frequency. By such monitoring action you can
“get the picture” of the traffic in your area. When the
approach controller has radar, radar traffic advisories
may be given to VFR pilots upon request.
REFERENCE-
AIM, Paragraph 4-1-14, Radar Traffic Information Service.
7-5-3. Obstructions To Flight
a. General. Many structures exist that could
significantly affect the safety of your flight when
operating below 500_feet AGL, and particularly
below 200 feet AGL. While 14_CFR Part 91.119
allows flight below 500_AGL when over sparsely
populated areas or open water, such operations are
very dangerous. At and below 200 feet AGL there are
numerous power lines, antenna towers, etc., that are
not marked and lighted as obstructions and; therefore,
may not be seen in time to avoid a collision. Notices
to Airmen (NOTAMs) are issued on those lighted
structures experiencing temporary light outages.
However, some time may pass before the FAA is
notified of these outages, and the NOTAM issued,
thus pilot vigilance is imperative.
b. Antenna Towers. Extreme caution should be
exercised when flying less than 2,000 feet AGL
because of numerous skeletal structures, such as radio
and television antenna towers, that exceed 1,000 feet
AGL with some extending higher than 2,000 feet
AGL. Most skeletal structures are supported by guy
wires which are very difficult to see in good weather
and can be invisible at dusk or during periods of
reduced visibility. These wires can extend about
1,500 feet horizontally from a structure; therefore, all
skeletal structures should be avoided horizontally by
AIM 2/14/7-5-2 Potential Flight Hazards
at least 2,000 feet. Additionally, new towers may not
be on your current chart because the information was
not received prior to the printing of the chart.
c. Overhead Wires. Overhead transmission and
utility lines often span approaches to runways,
natural flyways such as lakes, rivers, gorges, and
canyons, and cross other landmarks pilots frequently
follow such as highways, railroad tracks, etc. As with
antenna towers, these high voltage/power lines or the
supporting structures of these lines may not always be
readily visible and the wires may be virtually
impossible to see under certain conditions. In some
locations, the supporting structures of overhead
transmission lines are equipped with unique sequence
flashing white strobe light systems to indicate that
there are wires between the structures. However,
many power lines do not require notice to the FAA
and, therefore, are not marked and/or lighted. Many
of those that do require notice do not exceed 200 feet
AGL or meet the Obstruction Standard of 14 CFR
Part 77 and, therefore, are not marked and/or lighted.
All pilots are cautioned to remain extremely vigilant
for these power lines or their supporting structures
when following natural flyways or during the
approach and landing phase. This is particularly
important for seaplane and/or float equipped aircraft
when landing on, or departing from, unfamiliar lakes
or rivers.
d. Other Objects/Structures. There are other
objects or structures that could adversely affect your
flight such as construction cranes near an airport,
newly constructed buildings, new towers, etc. Many
of these structures do not meet charting requirements
or may not yet be charted because of the charting
cycle. Some structures do not require obstruction
marking and/or lighting and some may not be marked
and lighted even though the FAA recommended it.
7-5-4. Avoid Flight Beneath Unmanned
Balloons
a. The majority of unmanned free balloons
currently being operated have, extending below
them, either a suspension device to which the payload
or instrument package is attached, or a trailing wire
antenna, or both. In many instances these balloon
subsystems may be invisible to the pilot until the
aircraft is close to the balloon, thereby creating a
potentially dangerous situation. Therefore, good
judgment on the part of the pilot dictates that aircraft
should remain well clear of all unmanned free
balloons and flight below them should be avoided at
all times.
b. Pilots are urged to report any unmanned free
balloons sighted to the nearest FAA ground facility
with which communication is established. Such
information will assist FAA ATC facilities to identify
and flight follow unmanned free balloons operating
in the airspace.
7-5-5. Unmanned Aircraft Systems
a. Unmanned Aircraft Systems (UAS), formerly
referred to as “Unmanned Aerial Vehicles” (UAVs)
or “drones,” are having an increasing operational
presence in the NAS. Once the exclusive domain of
the military, UAS are now being operated by various
entities. Although these aircraft are “unmanned,”
UAS are flown by a remotely located pilot and crew.
Physical and performance characteristics of unmanned aircraft (UA) vary greatly and unlike model
aircraft that typically operate lower than 400 feet
AGL, UA may be found operating at virtually any
altitude and any speed. Sizes of UA can be as small
as several pounds to as large as a commercial
transport aircraft. UAS come in various categories
including airplane, rotorcraft, powered-lift (tilt-
rotor), and lighter-than-air. Propulsion systems of
UAS include a broad range of alternatives from
piston powered and turbojet engines to battery and
solar-powered electric motors.
b. To ensure segregation of UAS operations from
other aircraft, the military typically conducts UAS
operations within restricted or other special use
airspace. However, UAS operations are now being
approved in the NAS outside of special use airspace
through the use of FAA-issued Certificates of Waiver
or Authorization (COA) or through the issuance of a
special airworthiness certificate. COA and special
airworthiness approvals authorize UAS flight
operations to be contained within specific geographic
boundaries and altitudes, usually require coordination with an ATC facility, and typically require the
issuance of a NOTAM describing the operation to be
conducted. UAS approvals also require observers to
provide “see-and-avoid” capability to the UAS crew
and to provide the necessary compliance with 14 CFR
Section 91.113. For UAS operations approved at or
above FL180, UAS operate under the same
requirements as that of manned aircraft (i.e., flights
3/15/07 7110.65R CHG 2 AIM 7/31/08
AIM 2/14/08
7-5-3
Potential Flight Hazards
are operated under instrument flight rules, are in
communication with ATC, and are appropriately
equipped).
c. UAS operations may be approved at either
controlled or uncontrolled airports and are typically
disseminated by NOTAM. In all cases, approved
UAS operations shall comply with all applicable
regulations and/or special provisions specified in the
COA or in the operating limitations of the special
airworthiness certificate. At uncontrolled airports,
UAS operations are advised to operate well clear of
all known manned aircraft operations. Pilots of
manned aircraft are advised to follow normal
operating procedures and are urged to monitor the
CTAF for any potential UAS activity. At controlled
airports, local ATC procedures may be in place to
handle UAS operations and should not require any
special procedures from manned aircraft entering or
departing the traffic pattern or operating in the
vicinity of the airport.
d. In addition to approved UAS operations
described above, a recently approved agreement
between the FAA and the Department of Defense
authorizes small UAS operations wholly contained
within Class G airspace, and in no instance, greater
than 1200 feet AGL over military owned or leased
property. These operations do not require any special
authorization as long as the UA remains within the
lateral boundaries of the military installation as well
as other provisions including the issuance of a
NOTAM. Unlike special use airspace, these areas
may not be depicted on an aeronautical chart.
e. There are several factors a pilot should consider
regarding UAS activity in an effort to reduce
potential flight hazards. Pilots are urged to exercise
increased vigilance when operating in the vicinity of
restricted or other special use airspace, military
operations areas, and any military installation. Areas
with a preponderance of UAS activity are typically
noted on sectional charts advising pilots of this
activity. Since the size of a UA can be very small, they
may be difficult to see and track. If a UA is
encountered during flight, as with manned aircraft,
never assume that the pilot or crew of the UAS can see
you, maintain increased vigilance with the UA and
always be prepared for evasive action if necessary.
Always check NOTAMs for potential UAS activity
along the intended route of flight and exercise
increased vigilance in areas specified in the NOTAM.
7-5-6. Mountain Flying
a. Your first experience of flying over mountainous terrain (particularly if most of your flight time has
been over the flatlands of the midwest) could be a
never-to-be-forgotten nightmare if proper planning is
not done and if you are not aware of the potential
hazards awaiting. Those familiar section lines are not
present in the mountains; those flat, level fields for
forced landings are practically nonexistent; abrupt
changes in wind direction and velocity occur; severe
updrafts and downdrafts are common, particularly
near or above abrupt changes of terrain such as cliffs
or rugged areas; even the clouds look different and
can build up with startling rapidity. Mountain flying
need not be hazardous if you follow the recommendations below.
b. File a Flight Plan. Plan your route to avoid
topography which would prevent a safe forced
landing. The route should be over populated areas and
well known mountain passes. Sufficient altitude
should be maintained to permit gliding to a safe
landing in the event of engine failure.
c. Don’t fly a light aircraft when the winds aloft, at
your proposed altitude, exceed 35 miles per hour.
Expect the winds to be of much greater velocity over
mountain passes than reported a few miles from them.
Approach mountain passes with as much altitude as
possible. Downdrafts of from 1,500 to 2,000 feet per
minute are not uncommon on the leeward side.
d. Don’t fly near or above abrupt changes in
terrain. Severe turbulence can be expected, especially
in high wind conditions.
e. Understand Mountain Obscuration. The
term Mountain Obscuration (MTOS) is used to
describe a visibility condition that is distinguished
from IFR because ceilings, by definition, are
described as “above ground level” (AGL). In
mountainous terrain clouds can form at altitudes
significantly higher than the weather reporting
station and at the same time nearby mountaintops
may be obscured by low visibility. In these areas the
ground level can also vary greatly over a small area.
Beware if operating VFR-on-top. You could be
operating closer to the terrain than you think because
the tops of mountains are hidden in a cloud deck
below. MTOS areas are identified daily on The
Aviation Weather Center located at:
http://www.aviationweather.gov.
7/31/08 AIM
AIM 2/14/7-5-4 Potential Flight Hazards
f. Some canyons run into a dead end. Don’t fly so
far up a canyon that you get trapped. ALWAYS BE
ABLE TO MAKE A 180 DEGREE TURN!
g. VFR flight operations may be conducted at
night in mountainous terrain with the application of
sound judgment and common sense. Proper pre-flight
planning, giving ample consideration to winds and
weather, knowledge of the terrain and pilot
experience in mountain flying are prerequisites for
safety of flight. Continuous visual contact with the
surface and obstructions is a major concern and flight
operations under an overcast or in the vicinity of
clouds should be approached with extreme caution.
h. When landing at a high altitude field, the same
indicated airspeed should be used as at low elevation
fields. Remember: that due to the less dense air at
altitude, this same indicated airspeed actually results
in higher true airspeed, a faster landing speed, and
more important, a longer landing distance. During
gusty wind conditions which often prevail at high
altitude fields, a power approach and power landing
is recommended. Additionally, due to the faster
groundspeed, your takeoff distance will increase
considerably over that required at low altitudes.
i. Effects of Density Altitude. Performance
figures in the aircraft owner’s handbook for length of
takeoff run, horsepower, rate of climb, etc., are
generally based on standard atmosphere conditions
(59 degrees Fahrenheit (15 degrees Celsius), pressure
29.92 inches of mercury) at sea level. However,
inexperienced pilots, as well as experienced pilots,
may run into trouble when they encounter an
altogether different set of conditions. This is
particularly true in hot weather and at higher
elevations. Aircraft operations at altitudes above sea
level and at higher than standard temperatures are
commonplace in mountainous areas. Such operations
quite often result in a drastic reduction of aircraft
performance capabilities because of the changing air
density. Density altitude is a measure of air density.
It is not to be confused with pressure altitude, true
altitude or absolute altitude. It is not to be used as a
height reference, but as a determining criteria in the
performance capability of an aircraft. Air density
decreases with altitude. As air density decreases,
density altitude increases. The further effects of high
temperature and high humidity are cumulative,
resulting in an increasing high density altitude
condition. High density altitude reduces all aircraft
performance parameters. To the pilot, this means that
the normal horsepower output is reduced, propeller
efficiency is reduced and a higher true airspeed is
required to sustain the aircraft throughout its
operating parameters. It means an increase in runway
length requirements for takeoff and landings, and
decreased rate of climb. An average small airplane,
for example, requiring 1,000 feet for takeoff at sea
level under standard atmospheric conditions will
require a takeoff run of approximately 2,000 feet at an
operational altitude of 5,000 feet.
NOTE-
A turbo-charged aircraft engine provides some slight
advantage in that it provides sea level horsepower up to a
specified altitude above sea level.
1. Density Altitude Advisories. At airports
with elevations of 2,000 feet and higher, control
towers and FSSs will broadcast the advisory “Check
Density Altitude” when the temperature reaches a
predetermined level. These advisories will be
broadcast on appropriate tower frequencies or, where
available, ATIS. FSSs will broadcast these advisories
as a part of Local Airport Advisory, and on TWEB.
2. These advisories are provided by air traffic
facilities, as a reminder to pilots that high
temperatures and high field elevations will cause
significant changes in aircraft characteristics. The
pilot retains the responsibility to compute density
altitude, when appropriate, as a part of preflight
duties.
NOTE-
All FSSs will compute the current density altitude upon
request.
j. Mountain Wave. Many pilots go all their lives
without understanding what a mountain wave is.
Quite a few have lost their lives because of this lack
of understanding. One need not be a licensed
meteorologist to understand the mountain wave
phenomenon.
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Potential Flight Hazards
1. Mountain waves occur when air is being
blown over a mountain range or even the ridge of a
sharp bluff area. As the air hits the upwind side of the
range, it starts to climb, thus creating what is
generally a smooth updraft which turns into a
turbulent downdraft as the air passes the crest of the
ridge. From this point, for many miles downwind,
there will be a series of downdrafts and updrafts.
Satellite photos of the Rockies have shown mountain
waves extending as far as 700 miles downwind of the
range. Along the east coast area, such photos of the
Appalachian chain have picked up the mountain
wave phenomenon over a hundred miles eastward.
All it takes to form a mountain wave is wind blowing
across the range at 15 knots or better at an intersection
angle of not less than 30 degrees.
2. Pilots from flatland areas should understand
a few things about mountain waves in order to stay
out of trouble. When approaching a mountain range
from the upwind side (generally the west), there will
usually be a smooth updraft; therefore, it is not quite
as dangerous an area as the lee of the range. From the
leeward side, it is always a good idea to add an extra
thousand feet or so of altitude because downdrafts
can exceed the climb capability of the aircraft. Never
expect an updraft when approaching a mountain
chain from the leeward. Always be prepared to cope
with a downdraft and turbulence.
3. When approaching a mountain ridge from the
downwind side, it is recommended that the ridge be
approached at approximately a 45 degree angle to the
horizontal direction of the ridge. This permits a safer
retreat from the ridge with less stress on the aircraft
should severe turbulence and downdraft be experienced. If severe turbulence is encountered,
simultaneously reduce power and adjust pitch until
aircraft approaches maneuvering speed, then adjust
power and trim to maintain maneuvering speed and
fly away from the turbulent area.
7-5-7. Use of Runway Half-way Signs at
Unimproved Airports
When installed, runway half-way signs provide the
pilot with a reference point to judge takeoff
acceleration trends. Assuming that the runway length
is appropriate for takeoff (considering runway
condition and slope, elevation, aircraft weight, wind,
and temperature), typical takeoff acceleration should
allow the airplane to reach 70 percent of lift-off
airspeed by the midpoint of the runway. The “rule of
thumb” is that should airplane acceleration not allow
the airspeed to reach this value by the midpoint, the
takeoff should be aborted, as it may not be possible to
liftoff in the remaining runway.
Several points are important when considering using
this “rule of thumb”:
a. Airspeed indicators in small airplanes are not
required to be evaluated at speeds below stalling, and
may not be usable at 70 percent of liftoff airspeed.
b. This “rule of thumb” is based on a uniform
surface condition. Puddles, soft spots, areas of tall
and/or wet grass, loose gravel, etc., may impede
acceleration or even cause deceleration. Even if the
airplane achieves 70 percent of liftoff airspeed by the
midpoint, the condition of the remainder of the runway
may not allow further acceleration. The entire length
of the runway should be inspected prior to takeoff to
ensure a usable surface.
c. This “rule of thumb” applies only to runway
required for actual liftoff. In the event that obstacles
affect the takeoff climb path, appropriate distance
must be available after liftoff to accelerate to best angle
of climb speed and to clear the obstacles. This will, in
effect, require the airplane to accelerate to a higher
speed by midpoint, particularly if the obstacles are
close to the end of the runway. In addition, this
technique does not take into account the effects of
upslope or tailwinds on takeoff performance. These
factors will also require greater acceleration than
normal and, under some circumstances, prevent
takeoff entirely.
d. Use of this “rule of thumb” does not alleviate the
pilot’s responsibility to comply with applicable
Federal Aviation Regulations, the limitations and
performance data provided in the FAA approved
Airplane Flight Manual (AFM), or, in the absence of
an FAA approved AFM, other data provided by the
aircraft manufacturer.
In addition to their use during takeoff, runway
half-way signs offer the pilot increased awareness of
his or her position along the runway during landing
operations.
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NOTE-
No FAA standard exists for the appearance of the runway
half-way sign. FIG 7-5-1 shows a graphical depiction of
a typical runway half-way sign.
7-5-8. Seaplane Safety
a. Acquiring a seaplane class rating affords access
to many areas not available to landplane pilots.
Adding a seaplane class rating to your pilot certificate
can be relatively uncomplicated and inexpensive.
However, more effort is required to become a safe,
efficient, competent “bush” pilot. The natural hazards
of the backwoods have given way to modern
man-made hazards. Except for the far north, the
available bodies of water are no longer the exclusive
domain of the airman. Seaplane pilots must be
vigilant for hazards such as electric power lines,
power, sail and rowboats, rafts, mooring lines, water
skiers, swimmers, etc.
FIG 7-5-1
Typical Runway Half-way Sign
b. Seaplane pilots must have a thorough understanding of the right-of-way rules as they apply to
aircraft versus other vessels. Seaplane pilots are
expected to know and adhere to both the U.S. Coast
Guard's (USCG) Navigation Rules, International-Inland, and 14 CFR Section 91.115, Right-of-Way
Rules; Water Operations. The navigation rules of the
road are a set of collision avoidance rules as they
apply to aircraft on the water. A seaplane is
considered a vessel when on the water for the
purposes of these collision avoidance rules. In
general, a seaplane on the water shall keep well clear
of all vessels and avoid impeding their navigation.
The CFR requires, in part, that aircraft operating on
the water “. . . shall, insofar as possible, keep clear of
all vessels and avoid impeding their navigation, and
shall give way to any vessel or other aircraft that is
given the right-of-way . . . .” This means that a
seaplane should avoid boats and commercial
shipping when on the water. If on a collision course,
the seaplane should slow, stop, or maneuver to the
right, away from the bow of the oncoming vessel.
Also, while on the surface with an engine running, an
aircraft must give way to all nonpowered vessels.
Since a seaplane in the water may not be as
maneuverable as one in the air, the aircraft on the
water has right-of-way over one in the air, and one
taking off has right-of-way over one landing. A
seaplane is exempt from the USCG safety equipment
requirements, including the requirements for Personal Flotation Devices (PFD). Requiring seaplanes on
the water to comply with USCG equipment
requirements in addition to the FAA equipment
requirements would be an unnecessary burden on
seaplane owners and operators.
c. Unless they are under Federal jurisdiction,
navigable bodies of water are under the jurisdiction
of the state, or in a few cases, privately owned. Unless
they are specifically restricted, aircraft have as much
right to operate on these bodies of water as other
vessels. To avoid problems, check with Federal or
local officials in advance of operating on unfamiliar
waters. In addition to the agencies listed in
TBL 7-5-1, the nearest Flight Standards District
Office can usually offer some practical suggestions as
well as regulatory information. If you land on a
restricted body of water because of an inflight
emergency, or in ignorance of the restrictions you
have violated, report as quickly as practical to the
nearest local official having jurisdiction and explain
your situation.
d. When operating a seaplane over or into remote
areas, appropriate attention should be given to
survival gear. Minimum kits are recommended for
summer and winter, and are required by law for flight
into sparsely settled areas of Canada and Alaska.
Alaska State Department of Transportation and
Canadian Ministry of Transport officials can provide
specific information on survival gear requirements.
The kit should be assembled in one container and be
easily reachable and preferably floatable.
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Potential Flight Hazards
TBL 7-5-1
Jurisdictions Controlling Navigable Bodies of Water
Authority to Consult For Use of a Body of Water
Location Authority Contact
Wilderness Area U.S. Department
of Agriculture,
Forest Service
Local forest ranger
National Forest USDA Forest
Service
Local forest ranger
National Park U.S. Department
of the Interior,
National Park
Service
Local park ranger
Indian Reservation USDI, Bureau of
Indian Affairs
Local Bureau
office
State Park State government
or state forestry or
park service
Local state
aviation office for
further
information
Canadian National
and Provincial
Parks
Supervised and
restricted on an
individual basis
from province to
province and by
different
departments of the
Canadian
government;
consult Canadian
Flight Information
Manual and/or
Water Aerodrome
Supplement
Park
Superintendent in
an emergency
e. The FAA recommends that each seaplane owner
or operator provide flotation gear for occupants any
time a seaplane operates on or near water. 14 CFR
Section 91.205(b)(12) requires approved flotation
gear for aircraft operated for hire over water and
beyond power-off gliding distance from shore.
FAA-approved gear differs from that required for
navigable waterways under USCG rules. FAA-approved life vests are inflatable designs as compared
to the USCG’s noninflatable PFD’s that may consist
of solid, bulky material. Such USCG PFDs are
impractical for seaplanes and other aircraft because
they may block passage through the relatively narrow
exits available to pilots and passengers. Life vests
approved under Technical Standard Order (TSO)
TSO-C13E contain fully inflatable compartments.
The wearer inflates the compartments (AFTER
exiting the aircraft) primarily by independent CO2
cartridges, with an oral inflation tube as a backup. The
flotation gear also contains a water-activated,
self-illuminating signal light. The fact that pilots and
passengers can easily don and wear inflatable life
vests (when not inflated) provides maximum
effectiveness and allows for unrestricted movement.
It is imperative that passengers are briefed on the
location and proper use of available PFDs prior to
leaving the dock.
f. The FAA recommends that seaplane owners and
operators obtain Advisory Circular (AC) 91-69,
Seaplane Safety for 14 CFR Part 91 Operations, free
from the U.S. Department of Transportation,
Subsequent Distribution Office, SVC-121.23, Ardmore East Business Center, 3341 Q 75th Avenue,
Landover, MD 20785; fax: (301) 386-5394. The
USCG Navigation Rules International-Inland
(COMDTINSTM 16672.2B) is available for a fee
from the Government Printing Office by facsimile
request to (202) 512-2250, and can be ordered using
Mastercard or Visa.
7-5-9. Flight Operations in Volcanic Ash
a. Severe volcanic eruptions which send ash into
the upper atmosphere occur somewhere around the
world several times each year. Flying into a volcanic
ash cloud can be exceedingly dangerous. A
B747-200 lost all four engines after such an
encounter and a B747-400 had the same nearly
catastrophic experience. Piston-powered aircraft are
less likely to lose power but severe damage is almost
certain to ensue after an encounter with a volcanic ash
cloud which is only a few hours old.
b. Most important is to avoid any encounter with
volcanic ash. The ash plume may not be visible,
especially in instrument conditions or at night; and
even if visible, it is difficult to distinguish visually
between an ash cloud and an ordinary weather cloud.
Volcanic ash clouds are not displayed on airborne or
ATC radar. The pilot must rely on reports from air
traffic controllers and other pilots to determine the
location of the ash cloud and use that information to
remain well clear of the area. Every attempt should be
made to remain on the upwind side of the volcano.
c. It is recommended that pilots encountering an
ash cloud should immediately reduce thrust to idle
(altitude permitting), and reverse course in order to
escape from the cloud. Ash clouds may extend for
hundreds of miles and pilots should not attempt to fly
through or climb out of the cloud. In addition, the
following procedures are recommended:
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1. Disengage the autothrottle if engaged. This
will prevent the autothrottle from increasing engine
thrust;
2. Turn on continuous ignition;
3. Turn on all accessory airbleeds including all
air conditioning packs, nacelles, and wing anti-ice.
This will provide an additional engine stall margin by
reducing engine pressure.
d. The following has been reported by flightcrews
who have experienced encounters with volcanic dust
clouds:
1. Smoke or dust appearing in the cockpit.
2. An acrid odor similar to electrical smoke.
3. Multiple engine malfunctions, such as
compressor stalls, increasing EGT, torching from
tailpipe, and flameouts.
4. At night, St. Elmo’s fire or other static
discharges accompanied by a bright orange glow in
the engine inlets.
5. A fire warning in the forward cargo area.
e. It may become necessary to shut down and then
restart engines to prevent exceeding EGT limits.
Volcanic ash may block the pitot system and result in
unreliable airspeed indications.
f. If you see a volcanic eruption and have not been
previously notified of it, you may have been the first
person to observe it. In this case, immediately contact
ATC and alert them to the existence of the eruption.
If possible, use the Volcanic Activity Reporting form
(VAR) depicted in Appendix 2 of this manual.
Items 1 through 8 of the VAR should be transmitted
immediately. The information requested in
items 9 through 16 should be passed after landing. If
a VAR form is not immediately available, relay
enough information to identify the position and
nature of the volcanic activity. Do not become
unnecessarily alarmed if there is merely steam or very
low-level eruptions of ash.
g. When landing at airports where volcanic ash has
been deposited on the runway, be aware that even a
thin layer of dry ash can be detrimental to braking
action. Wet ash on the runway may also reduce
effectiveness of braking. It is recommended that
reverse thrust be limited to minimum practical to
reduce the possibility of reduced visibility and engine
ingestion of airborne ash.
h. When departing from airports where volcanic
ash has been deposited, it is recommended that pilots
avoid operating in visible airborne ash. Allow ash to
settle before initiating takeoff roll. It is also
recommended that flap extension be delayed until
initiating the before takeoff checklist and that a
rolling takeoff be executed to avoid blowing ash back
into the air.
7-5-10. Emergency Airborne Inspection of
Other Aircraft
a. Providing airborne assistance to another aircraft
may involve flying in very close proximity to that
aircraft. Most pilots receive little, if any, formal
training or instruction in this type of flying activity.
Close proximity flying without sufficient time to plan
(i.e., in an emergency situation), coupled with the
stress involved in a perceived emergency can be
hazardous.
b. The pilot in the best position to assess the
situation should take the responsibility of coordinating the airborne intercept and inspection, and take
into account the unique flight characteristics and
differences of the category(s) of aircraft involved.
c. Some of the safety considerations are:
1. Area, direction and speed of the intercept;
2. Aerodynamic effects (i.e., rotorcraft downwash);
3. Minimum safe separation distances;
4. Communications requirements, lost communications procedures, coordination with ATC;
5. Suitability of diverting the distressed aircraft
to the nearest safe airport; and
6. Emergency actions to terminate the intercept.
d. Close proximity, inflight inspection of another
aircraft is uniquely hazardous. The pilot-in-
command of the aircraft experiencing the
problem/emergency must not relinquish control of
the situation and/or jeopardize the safety of their
aircraft. The maneuver must be accomplished with
minimum risk to both aircraft.
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Potential Flight Hazards
7-5-11. Precipitation Static
a. Precipitation static is caused by aircraft in flight
coming in contact with uncharged particles. These
particles can be rain, snow, fog, sleet, hail, volcanic
ash, dust; any solid or liquid particles. When the
aircraft strikes these neutral particles the positive
element of the particle is reflected away from the
aircraft and the negative particle adheres to the skin
of the aircraft. In a very short period of time a
substantial negative charge will develop on the skin
of the aircraft. If the aircraft is not equipped with
static dischargers, or has an ineffective static
discharger system, when a sufficient negative voltage
level is reached, the aircraft may go into
“CORONA.” That is, it will discharge the static
electricity from the extremities of the aircraft, such as
the wing tips, horizontal stabilizer, vertical stabilizer,
antenna, propeller tips, etc. This discharge of static
electricity is what you will hear in your headphones
and is what we call P-static.
b. A review of pilot reports often shows different
symptoms with each problem that is encountered.
The following list of problems is a summary of many
pilot reports from many different aircraft. Each
problem was caused by P-static:
1. Complete loss of VHF communications.
2. Erroneous magnetic compass readings
(30 percent in error).
3. High pitched squeal on audio.
4. Motor boat sound on audio.
5. Loss of all avionics in clouds.
6. VLF navigation system inoperative most of
the time.
7. Erratic instrument readouts.
8. Weak transmissions and poor receptivity of
radios.
9. “St. Elmo’s Fire” on windshield.
c. Each of these symptoms is caused by one
general problem on the airframe. This problem is the
inability of the accumulated charge to flow easily to
the wing tips and tail of the airframe, and properly
discharge to the airstream.
d. Static dischargers work on the principal of
creating a relatively easy path for discharging
negative charges that develop on the aircraft by using
a discharger with fine metal points, carbon coated
rods, or carbon wicks rather than wait until a large
charge is developed and discharged off the trailing
edges of the aircraft that will interfere with avionics
equipment. This process offers approximately
50 decibels (dB) static noise reduction which is
adequate in most cases to be below the threshold of
noise that would cause interference in avionics
equipment.
e. It is important to remember that precipitation
static problems can only be corrected with the proper
number of quality static dischargers, properly
installed on a properly bonded aircraft. P-static is
indeed a problem in the all weather operation of the
aircraft, but there are effective ways to combat it. All
possible methods of reducing the effects of P-static
should be considered so as to provide the best
possible performance in the flight environment.
f. A wide variety of discharger designs is available
on the commercial market. The inclusion of
well-designed dischargers may be expected to
improve airframe noise in P-static conditions by as
much as 50 dB. Essentially, the discharger provides
a path by which accumulated charge may leave the
airframe quietly. This is generally accomplished by
providing a group of tiny corona points to permit
onset of corona-current flow at a low aircraft
potential. Additionally, aerodynamic design of
dischargers to permit corona to occur at the lowest
possible atmospheric pressure also lowers the corona
threshold. In addition to permitting a low-potential
discharge, the discharger will minimize the radiation
of radio frequency (RF) energy which accompanies
the corona discharge, in order to minimize effects of
RF components at communications and navigation
frequencies on avionics performance. These effects
are reduced through resistive attachment of the
corona point(s) to the airframe, preserving direct
current connection but attenuating the higher-frequency components of the discharge.
g. Each manufacturer of static dischargers offers
information concerning appropriate discharger location on specific airframes. Such locations emphasize
the trailing outboard surfaces of wings and horizontal
tail surfaces, plus the tip of the vertical stabilizer,
where charge tends to accumulate on the airframe.
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Sufficient dischargers must be provided to allow for
current-carrying capacity which will maintain
airframe potential below the corona threshold of the
trailing edges.
h. In order to achieve full performance of avionic
equipment, the static discharge system will require
periodic maintenance. A pilot knowledgeable of
P-static causes and effects is an important element in
assuring optimum performance by early recognition
of these types of problems.
7-5-12. Light Amplification by Stimulated
Emission of Radiation (Laser) Operations
and Reporting Illumination of Aircraft
a. Lasers have many applications. Of concern to
users of the National Airspace System are those laser
events that may affect pilots, e.g., outdoor laser light
shows or demonstrations for entertainment and
advertisements at special events and theme parks.
Generally, the beams from these events appear as
bright blue-green in color; however, they may be red,
yellow, or white. However, some laser systems
produce light which is invisible to the human eye.
b. FAA regulations prohibit the disruption of
aviation activity by any person on the ground or in the
air. The FAA and the Food and Drug Administration
(the Federal agency that has the responsibility to
enforce compliance with Federal requirements for
laser systems and laser light show products) are
working together to ensure that operators of these
devices do not pose a hazard to aircraft operators.
c. Pilots should be aware that illumination from
these laser operations are able to create temporary
vision impairment miles from the actual location. In
addition, these operations can produce permanent eye
damage. Pilots should make themselves aware of
where these activities are being conducted and avoid
these areas if possible.
d. Recent and increasing incidents of unauthorized illumination of aircraft by lasers, as well as the
proliferation and increasing sophistication of laser
devices available to the general public, dictates that
the FAA, in coordination with other government
agencies, take action to safeguard flights from these
unauthorized illuminations.
e. Pilots should report laser illumination activity to
the controlling Air Traffic Control facilities, Federal
Contract Towers or Flight Service Stations as soon as
possible after the event. The following information
should be included:
1. UTC Date and Time of Event.
2. Call Sign or Aircraft Registration Number.
3. Type Aircraft.
4. Nearest Major City.
5. Altitude.
6. Location of Event (Latitude/Longitude and/
or Fixed Radial Distance (FRD)).
7. Brief Description of the Event and any other
Pertinent Information.
f. Pilots are also encouraged to complete the Laser
Beam Exposure Questionnaire (See Appendix 3), and
fax it to the Washington Operations Center Complex
(WOCC) as soon as possible after landing.
g. When a laser event is reported to an air traffic
facility, a general caution warning will be broadcasted on all appropriate frequencies every
five minutes for 20 minutes and broadcasted on the
ATIS for one hour following the report.
PHRASEOLOGY-
UNAUTHORIZED LASER ILLUMINATION EVENT,
(UTC time), (location), (altitude), (color), (direction).
EXAMPLE-
“Unauthorized laser illumination event, at 0100z, 8 mile
final runway 18R at 3,000 feet, green laser from the
southwest.”
REFERENCE-
FAAO 7110.65, Unauthorized Laser Illumination of Aircraft,
Para 10-2-14.
FAAO 7210.3, Reporting Laser Illumination of Aircraft, Para 2-1-27.
h. When these activities become known to the
FAA, Notices to Airmen (NOTAMs) are issued to
inform the aviation community of the events. Pilots
should consult NOTAMs or the Special Notices
section of the Airport/Facility Directory for information regarding these activities.
7-5-13. Flying in Flat Light and White Out
Conditions
a. Flat Light. Flat light is an optical illusion, also
known as “sector or partial white out.” It is not as
severe as “white out” but the condition causes pilots
to lose their depth-of-field and contrast in vision.
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Potential Flight Hazards
Flat light conditions are usually accompanied by
overcast skies inhibiting any visual clues. Such
conditions can occur anywhere in the world,
primarily in snow covered areas but can occur in dust,
sand, mud flats, or on glassy water. Flat light can
completely obscure features of the terrain, creating an
inability to distinguish distances and closure rates.
As a result of this reflected light, it can give pilots the
illusion that they are ascending or descending when
they may actually be flying level. However, with
good judgment and proper training and planning, it is
possible to safely operate an aircraft in flat light
conditions.
b. White Out. As defined in meteorological
terms, white out occurs when a person becomes
engulfed in a uniformly white glow. The glow is a
result of being surrounded by blowing snow, dust,
sand, mud or water. There are no shadows, no horizon
or clouds and all depth-of-field and orientation are
lost. A white out situation is severe in that there are
no visual references. Flying is not recommended in
any white out situation. Flat light conditions can lead
to a white out environment quite rapidly, and both
atmospheric conditions are insidious; they sneak up
on you as your visual references slowly begin to
disappear. White out has been the cause of several
aviation accidents.
c. Self Induced White Out. This effect typically
occurs when a helicopter takes off or lands on a
snow-covered area. The rotor down wash picks up
particles and re-circulates them through the rotor
down wash. The effect can vary in intensity
depending upon the amount of light on the surface.
This can happen on the sunniest, brightest day with
good contrast everywhere. However, when it
happens, there can be a complete loss of visual clues.
If the pilot has not prepared for this immediate loss of
visibility, the results can be disastrous. Good
planning does not prevent one from encountering flat
light or white out conditions.
d. Never take off in a white out situation.
1. Realize that in flat light conditions it may be
possible to depart but not to return to that site. During
takeoff, make sure you have a reference point. Do not
lose sight of it until you have a departure reference
point in view. Be prepared to return to the takeoff
reference if the departure reference does not come
into view.
2. Flat light is common to snow skiers. One way
to compensate for the lack of visual contrast and
depth-of-field loss is by wearing amber tinted lenses
(also known as blue blockers). Special note of
caution: Eyewear is not ideal for every pilot. Take
into consideration personal factors -age, light
sensitivity, and ambient lighting conditions.
3. So what should a pilot do when all visual
references are lost?
(a) Trust the cockpit instruments.
(b) Execute a 180 degree turnaround and start
looking for outside references.
(c) Above all -fly the aircraft.
e. Landing in Low Light Conditions. When
landing in a low light condition -use extreme
caution. Look for intermediate reference points, in
addition to checkpoints along each leg of the route for
course confirmation and timing. The lower the
ambient light becomes, the more reference points a
pilot should use.
f. Airport Landings.
1. Look for features around the airport or
approach path that can be used in determining depth
perception. Buildings, towers, vehicles or other
aircraft serve well for this measurement. Use
something that will provide you with a sense of height
above the ground, in addition to orienting you to the
runway.
2. Be cautious of snowdrifts and snow banks -
anything that can distinguish the edge of the runway.
Look for subtle changes in snow texture or shading to
identify ridges or changes in snow depth.
g. Off-Airport Landings.
1. In the event of an off-airport landing, pilots
have used a number of different visual cues to gain
reference. Use whatever you must to create the
contrast you need. Natural references seem to work
best (trees, rocks, snow ribs, etc.)
(a) Over flight.
(b) Use of markers.
(c) Weighted flags.
(d) Smoke bombs.
(e) Any colored rags.
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(f) Dye markers.
(g) Kool-aid.
(h) Trees or tree branches.
2. It is difficult to determine the depth of snow
in areas that are level. Dropping items from the
aircraft to use as reference points should be used as a
visual aid only and not as a primary landing reference.
Unless your marker is biodegradable, be sure to
retrieve it after landing. Never put yourself in a
position where no visual references exist.
3. Abort landing if blowing snow obscures your
reference. Make your decisions early. Don’t assume
you can pick up a lost reference point when you get
closer.
4. Exercise extreme caution when flying from
sunlight into shade. Physical awareness may tell you
that you are flying straight but you may actually be in
a spiral dive with centrifugal force pressing against
you. Having no visual references enhances this
illusion. Just because you have a good visual
reference does not mean that it’s safe to continue.
There may be snow-covered terrain not visible in the
direction that you are traveling. Getting caught in a no
visual reference situation can be fatal.
h. Flying Around a Lake.
1. When flying along lakeshores, use them as a
reference point. Even if you can see the other side,
realize that your depth perception may be poor. It is
easy to fly into the surface. If you must cross the lake,
check the altimeter frequently and maintain a safe
altitude while you still have a good reference. Don’t
descend below that altitude.
2. The same rules apply to seemingly flat areas
of snow. If you don’t have good references, avoid
going there.
i. Other Traffic. Be on the look out for other
traffic in the area. Other aircraft may be using your
same reference point. Chances are greater of
colliding with someone traveling in the same
direction as you, than someone flying in the opposite
direction.
j. Ceilings. Low ceilings have caught many pilots
off guard. Clouds do not always form parallel to the
surface, or at the same altitude. Pilots may try to
compensate for this by flying with a slight bank and
thus creating a descending turn.
k. Glaciers. Be conscious of your altitude when
flying over glaciers. The glaciers may be rising faster
than you are climbing.
7-5-14. Operations in Ground Icing
Conditions
a. The presence of aircraft airframe icing during
takeoff, typically caused by improper or no deicing of
the aircraft being accomplished prior to flight has
contributed to many recent accidents in turbine
aircraft. The General Aviation Joint Steering
Committee (GAJSC) is the primary vehicle for
government-industry cooperation, communication,
and coordination on GA accident mitigation. The
Turbine Aircraft Operations Subgroup (TAOS)
works to mitigate accidents in turbine accident
aviation. While there is sufficient information and
guidance currently available regarding the effects of
icing on aircraft and methods for deicing, the TAOS
has developed a list of recommended actions to
further assist pilots and operators in this area.
While the efforts of the TAOS specifically focus on
turbine aircraft, it is recognized that their recommendations are applicable to and can be adapted for the
pilot of a small, piston powered aircraft too.
b. The following recommendations are offered:
1. Ensure that your aircraft’s lift-generating
surfaces are COMPLETELY free of contamination
before flight through a tactile (hands on) check of the
critical surfaces when feasible. Even when otherwise
permitted, operators should avoid smooth or polished
frost on lift-generating surfaces as an acceptable
preflight condition.
2. Review and refresh your cold weather
standard operating procedures.
3. Review and be familiar with the Airplane
Flight Manual (AFM) limitations and procedures
necessary to deal with icing conditions prior to flight,
as well as in flight.
4. Protect your aircraft while on the ground, if
possible, from sleet and freezing rain by taking
advantage of aircraft hangars.
5. Take full advantage of the opportunities
available at airports for deicing. Do not refuse deicing
services simply because of cost.
3/15/07 7110.65R CHG 2 AIM 7/31/08
AIM 2/14/08
7-5-13
Potential Flight Hazards
6. Always consider canceling or delaying a
flight if weather conditions do not support a safe
operation.
c. If you haven’t already developed a set of
Standard Operating Procedures for cold weather
operations, they should include:
1. Procedures based on information that is
applicable to the aircraft operated, such as AFM
limitations and procedures;
2. Concise and easy to understand guidance that
outlines best operational practices;
3. A systematic procedure for recognizing,
evaluating and addressing the associated icing risk,
and offer clear guidance to mitigate this risk;
4. An aid (such as a checklist or reference cards)
that is readily available during normal day-to-day
aircraft operations.
d. There are several sources for guidance relating
to airframe icing, including:
1. http://aircrafticing.grc.nasa.gov/index.html
2. http://www.ibac.org/is-bao/isbao.htm
3. http://www.natasafety1st.org/bus_deice.htm
4. Advisory Circular (AC) 91-74, Pilot Guide,
Flight in Icing Conditions.
5. AC 135-17, Pilot Guide Small Aircraft
Ground Deicing.
6. AC 135-9, FAR Part 135 Icing Limitations.
7. AC 120-60, Ground Deicing and Anti-icing
Program.
8. AC 135-16, Ground Deicing and Anti-icing
Training and Checking.
The FAA Approved Deicing Program Updates is
published annually as a Flight Standards Information
Bulletin for Air Transportation and contains detailed
information on deicing and anti-icing procedures and
holdover times. It may be accessed at the following
web site by selecting the current year’s information
bulletins:
http://www.faa.gov/library/manuals/examiners_inspe
ctors/8400/fsat
7/31/08 AIM
AIM 2/14/08
7-6-1
Safety, Accident, and Hazard Reports
Section 6. Safety, Accident, and Hazard Reports
7-6-1. Aviation Safety Reporting Program
a. The FAA has established a voluntary Aviation
Safety Reporting Program designed to stimulate the
free and unrestricted flow of information concerning
deficiencies and discrepancies in the aviation system.
This is a positive program intended to ensure the
safest possible system by identifying and correcting
unsafe conditions before they lead to accidents. The
primary objective of the program is to obtain
information to evaluate and enhance the safety and
efficiency of the present system.
b. This cooperative safety reporting program
invites pilots, controllers, flight attendants, mainte-
nance personnel and other users of the airspace
system, or any other person, to file written reports of
actual or potential discrepancies and deficiencies
involving the safety of aviation operations. The
operations covered by the program include departure,
en route, approach, and landing operations and
procedures, air traffic control procedures and
equipment, crew and air traffic control communica-
tions, aircraft cabin operations, aircraft movement on
the airport, near midair collisions, aircraft mainte-
nance and record keeping and airport conditions or
services.
c. The report should give the date, time, location,
persons and aircraft involved (if applicable), nature
of the event, and all pertinent details.
d. To ensure receipt of this information, the
program provides for the waiver of certain
disciplinary actions against persons, including pilots
and air traffic controllers, who file timely written
reports concerning potentially unsafe incidents. To be
considered timely, reports must be delivered or
postmarked within 10 days of the incident unless that
period is extended for good cause. Reports should be
submitted on NASA ARC Forms_277, which are
available free of charge, postage prepaid, at FAA
Flight Standards District Offices and Flight Service
Stations, and from NASA, ASRS, PO Box 189,
Moffet Field, CA 94035.
e. The FAA utilizes the National Aeronautics and
Space Administration (NASA) to act as an
independent third party to receive and analyze reports
submitted under the program. This program is
described in AC_00-46, Aviation Safety Reporting
Program.
7-6-2. Aircraft Accident and Incident
Reporting
a. Occurrences Requiring Notification. The
operator of an aircraft shall immediately, and by the
most expeditious means available, notify the nearest
National Transportation Safety Board (NTSB) Field
Office when:
1. An aircraft accident or any of the following
listed incidents occur:
(a) Flight control system malfunction or
failure.
(b) Inability of any required flight crew
member to perform their normal flight duties as a
result of injury or illness.
(c) Failure of structural components of a
turbine engine excluding compressor and turbine
blades and vanes.
(d) Inflight fire.
(e) Aircraft collide in flight.
(f) Damage to property, other than the
aircraft, estimated to exceed $25,000 for repair
(including materials and labor) or fair market value in
the event of total loss, whichever is less.
(g) For large multi-engine aircraft (more than
12,500 pounds maximum certificated takeoff
weight):
(1) Inflight failure of electrical systems
which requires the sustained use of an emergency bus
powered by a back-up source such as a battery,
auxiliary power unit, or air-driven generator to retain
flight control or essential instruments;
(2) Inflight failure of hydraulic systems
that results in sustained reliance on the sole remaining
hydraulic or mechanical system for movement of
flight control surfaces;
(3) Sustained loss of the power or thrust
produced by two or more engines; and
(4) An evacuation of aircraft in which an
emergency egress system is utilized.
AIM 2/14/08
7-6-2 Safety, Accident, and Hazard Reports
2. An aircraft is overdue and is believed to have
been involved in an accident.
b. Manner of Notification.
1. The most expeditious method of notification
to the NTSB by the operator will be determined by the
circumstances existing at that time. The NTSB has
advised that any of the following would be
considered examples of the type of notification that
would be acceptable:
(a) Direct telephone notification.
(b) Telegraphic notification.
(c) Notification to the FAA who would in turn
notify the NTSB by direct communication; i.e.,_dis-
patch or telephone.
c. Items to be Included in Notification. The
notification required above shall contain the
following information, if available:
1. Type, nationality, and registration marks of
the aircraft.
2. Name of owner and operator of the aircraft.
3. Name of the pilot-in-command.
4. Date and time of the accident, or incident.
5. Last point of departure, and point of intended
landing of the aircraft.
6. Position of the aircraft with reference to some
easily defined geographical point.
7. Number of persons aboard, number killed,
and number seriously injured.
8. Nature of the accident, or incident, the
weather, and the extent of damage to the aircraft so far
as is known; and
9. A description of any explosives, radioactive
materials, or other dangerous articles carried.
d. Follow-up Reports.
1. The operator shall file a report on NTSB
Form 6120.1 or 6120.2, available from NTSB Field
Offices or from the NTSB, Washington, DC, 20594:
(a) Within 10 days after an accident;
(b) When, after 7 days, an overdue aircraft is
still missing;
(c) A report on an incident for which
notification is required as described in subpara-
graph_a(1) shall be filed only as requested by an
authorized representative of the NTSB.
2. Each crewmember, if physically able at the
time the report is submitted, shall attach a statement
setting forth the facts, conditions, and circumstances
relating to the accident or incident as they appeared.
If the crewmember is incapacitated, a statement shall
be submitted as soon as physically possible.
e. Where to File the Reports.
1. The operator of an aircraft shall file with the
NTSB Field Office nearest the accident or incident
any report required by this section.
2. The NTSB Field Offices are listed under U.S.
Government in the telephone directories in the
following cities: Anchorage, AK; Atlanta, GA;
Chicago, IL; Denver, CO; Fort Worth, TX;
Los_Angeles, CA; Miami, FL; Parsippany, NJ;
Seattle, WA.
7-6-3. Near Midair Collision Reporting
a. Purpose and Data Uses. The primary purpose
of the Near Midair Collision (NMAC) Reporting
Program is to provide information for use in
enhancing the safety and efficiency of the National
Airspace System. Data obtained from NMAC reports
are used by the FAA to improve the quality of FAA
services to users and to develop programs, policies,
and procedures aimed at the reduction of NMAC
occurrences. All NMAC reports are thoroughly
investigated by Flight Standards Facilities in
coordination with Air Traffic Facilities. Data from
these investigations are transmitted to FAA Head-
quarters in Washington, DC, where they are compiled
and analyzed, and where safety programs and
recommendations are developed.
b. Definition. A near midair collision is defined
as an incident associated with the operation of an
aircraft in which a possibility of collision occurs as a
result of proximity of less than 500 feet to another
aircraft, or a report is received from a pilot or a flight
crew member stating that a collision hazard existed
between two or more aircraft.
c. Reporting Responsibility. It is the responsi-
bility of the pilot and/or flight crew to determine
whether a near midair collision did actually occur
and, if so, to initiate a NMAC report. Be specific, as
AIM 2/14/08
7-6-3
Safety, Accident, and Hazard Reports
ATC will not interpret a casual remark to mean that
a NMAC is being reported. The pilot should state “I
wish to report a near midair collision.”
d. Where to File Reports. Pilots and/or flight
crew members involved in NMAC occurrences are
urged to report each incident immediately:
1. By radio or telephone to the nearest FAA ATC
facility or FSS.
2. In writing, in lieu of the above, to the nearest
Flight Standards District Office (FSDO).
e. Items to be Reported.
1. Date and time (UTC) of incident.
2. Location of incident and altitude.
3. Identification and type of reporting aircraft,
aircrew destination, name and home base of pilot.
4. Identification and type of other aircraft,
aircrew destination, name and home base of pilot.
5. Type of flight plans; station altimeter setting
used.
6. Detailed weather conditions at altitude or
flight level.
7. Approximate courses of both aircraft:
indicate if one or both aircraft were climbing or
descending.
8. Reported separation in distance at first
sighting, proximity at closest point horizontally and
vertically, and length of time in sight prior to evasive
action.
9. Degree of evasive action taken, if any (from
both aircraft, if possible).
10. Injuries, if any.
f. Investigation. The FSDO in whose area the
incident occurred is responsible for the investigation
and reporting of NMACs.
g. Existing radar, communication, and weather
data will be examined in the conduct of the
investigation. When possible, all cockpit crew
members will be interviewed regarding factors
involving the NMAC incident. Air traffic controllers
will be interviewed in cases where one or more of the
involved aircraft was provided ATC service. Both
flight and ATC procedures will be evaluated. When
the investigation reveals a violation of an FAA
regulation, enforcement action will be pursued.
7-6-4. Unidentified Flying Object (UFO)
Reports
a. Persons wanting to report UFO/Unexplained
Phenomena activity should contact an UFO/Unex-
plained Phenomena Reporting Data Collection
Center, such as the National Institute for Discovery
Sciences (NIDS), the National UFO Reporting
Center, etc.
b. If concern is expressed that life or property
might be endangered, report the activity to the local
law enforcement department.
AIM 2/14/08
8-1-1
Fitness for Flight
Chapter 8. Medical Facts for Pilots
Section 1. Fitness for Flight
8-1-1. Fitness For Flight
a. Medical Certification.
1. All pilots except those flying gliders and free
air balloons must possess valid medical certificates in
order to exercise the privileges of their airman
certificates. The periodic medical examinations
required for medical certification are conducted by
designated Aviation Medical Examiners, who are
physicians with a special interest in aviation safety
and training in aviation medicine.
2. The standards for medical certification are
contained in 14 CFR Part 67. Pilots who have a
history of certain medical conditions described in
these standards are mandatorily disqualified from
flying. These medical conditions include a
personality disorder manifested by overt acts, a
psychosis, alcoholism, drug dependence, epilepsy,
an_unexplained disturbance of consciousness,
myocardial infarction, angina pectoris and diabetes
requiring medication for its control. Other medical
conditions may be temporarily disqualifying, such as
acute infections, anemia, and peptic ulcer. Pilots who
do not meet medical standards may still be qualified
under special issuance provisions or the exemption
process. This may require that either additional
medical information be provided or practical flight
tests be conducted.
3. Student pilots should visit an Aviation
Medical Examiner as soon as possible in their flight
training in order to avoid unnecessary training
expenses should they not meet the medical standards.
For the same reason, the student pilot who plans to
enter commercial aviation should apply for the
highest class of medical certificate that might be
necessary in the pilot's career.
CAUTION-
The CFRs prohibit a pilot who possesses a current
medical certificate from performing crewmember duties
while the pilot has a known medical condition or increase
of a known medical condition that would make the pilot
unable to meet the standards for the medical certificate.
b. Illness.
1. Even a minor illness suffered in day-to-day
living can seriously degrade performance of many
piloting tasks vital to safe flight. Illness can produce
fever and distracting symptoms that can impair
judgment, memory, alertness, and the ability to make
calculations. Although symptoms from an illness
may be under adequate control with a medication, the
medication itself may decrease pilot performance.
2. The safest rule is not to fly while suffering
from any illness. If this rule is considered too
stringent for a particular illness, the pilot should
contact an Aviation Medical Examiner for advice.
c. Medication.
1. Pilot performance can be seriously degraded
by both prescribed and over-the-counter medications,
as well as by the medical conditions for which they
are taken. Many medications, such as tranquilizers,
sedatives, strong pain relievers, and cough-suppres-
sant preparations, have primary effects that may
impair judgment, memory, alertness, coordination,
vision, and the ability to make calculations. Others,
such as antihistamines, blood pressure drugs, muscle
relaxants, and agents to control diarrhea and motion
sickness, have side effects that may impair the same
critical functions. Any medication that depresses the
nervous system, such as a sedative, tranquilizer or
antihistamine, can make a pilot much more
susceptible to hypoxia.
2. The CFRs prohibit pilots from performing
crewmember duties while using any medication that
affects the faculties in any way contrary to safety. The
safest rule is not to fly as a crewmember while taking
any medication, unless approved to do so by the FAA.
d. Alcohol.
1. Extensive research has provided a number of
facts about the hazards of alcohol consumption and
flying. As little as one ounce of liquor, one bottle of
beer or four ounces of wine can impair flying skills,
with the alcohol consumed in these drinks being
detectable in the breath and blood for at least 3 hours.
Even after the body completely destroys a moderate
amount of alcohol, a pilot can still be severely
AIM 2/14/08
8-1-2 Fitness for Flight
impaired for many hours by hangover. There is
simply no way of increasing the destruction of
alcohol or alleviating a hangover. Alcohol also
renders a pilot much more susceptible to disorienta-
tion and hypoxia.
2. A consistently high alcohol related fatal
aircraft accident rate serves to emphasize that alcohol
and flying are a potentially lethal combination. The
CFRs prohibit pilots from performing crewmember
duties within 8 hours after drinking any alcoholic
beverage or while under the influence of alcohol.
However, due to the slow destruction of alcohol, a
pilot may still be under influence 8 hours after
drinking a moderate amount of alcohol. Therefore, an
excellent rule is to allow at least 12 to 24 hours
between “bottle and throttle,” depending on the
amount of alcoholic beverage consumed.
e. Fatigue.
1. Fatigue continues to be one of the most
treacherous hazards to flight safety, as it may not be
apparent to a pilot until serious errors are made.
Fatigue is best described as either acute (short-term)
or chronic (long-term).
2. A normal occurrence of everyday living,
acute fatigue is the tiredness felt after long periods of
physical and mental strain, including strenuous
muscular effort, immobility, heavy mental workload,
strong emotional pressure, monotony, and lack of
sleep. Consequently, coordination and alertness, so
vital to safe pilot performance, can be reduced. Acute
fatigue is prevented by adequate rest and sleep, as
well as by regular exercise and proper nutrition.
3. Chronic fatigue occurs when there is not
enough time for full recovery between episodes of
acute fatigue. Performance continues to fall off, and
judgment becomes impaired so that unwarranted
risks may be taken. Recovery from chronic fatigue
requires a prolonged period of rest.
f. Stress.
1. Stress from the pressures of everyday living
can impair pilot performance, often in very subtle
ways. Difficulties, particularly at work, can occupy
thought processes enough to markedly decrease
alertness. Distraction can so interfere with judgment
that unwarranted risks are taken, such as flying into
deteriorating weather conditions to keep on schedule.
Stress and fatigue (see above) can be an extremely
hazardous combination.
2. Most pilots do not leave stress “on the
ground.” Therefore, when more than usual difficul-
ties are being experienced, a pilot should consider
delaying flight until these difficulties are satisfac-
torily resolved.
g. Emotion.
Certain emotionally upsetting events, including a
serious argument, death of a family member,
separation or divorce, loss of job, and financial
catastrophe, can render a pilot unable to fly an aircraft
safely. The emotions of anger, depression, and
anxiety from such events not only decrease alertness
but also may lead to taking risks that border on
self-destruction. Any pilot who experiences an
emotionally upsetting event should not fly until
satisfactorily recovered from it.
h. Personal Checklist. Aircraft accident statis-
tics show that pilots should be conducting preflight
checklists on themselves as well as their aircraft for
pilot impairment contributes to many more accidents
than failures of aircraft systems. A personal checklist,
which includes all of the categories of pilot
impairment as discussed in this section, that can be
easily committed to memory is being distributed by
the FAA in the form of a wallet-sized card.
i. PERSONAL CHECKLIST. I'm physically
and mentally safe to fly; not being impaired by:
Illness
Medication
Stress
Alcohol
Fatigue
Emotion
AIM 2/14/08
8-1-3
Fitness for Flight
8-1-2. Effects of Altitude
a. Hypoxia.
1. Hypoxia is a state of oxygen deficiency in the
body sufficient to impair functions of the brain and
other organs. Hypoxia from exposure to altitude is
due only to the reduced barometric pressures
encountered at altitude, for the concentration of
oxygen in the atmosphere remains about 21 percent
from the ground out to space.
2. Although a deterioration in night vision
occurs at a cabin pressure altitude as low as
5,000_feet, other significant effects of altitude
hypoxia usually do not occur in the normal healthy
pilot below 12,000 feet. From 12,000 to 15,000 feet
of altitude, judgment, memory, alertness, coordina-
tion and ability to make calculations are impaired,
and headache, drowsiness, dizziness and either a
sense of well-being (euphoria) or belligerence occur.
The effects appear following increasingly shorter
periods of exposure to increasing altitude. In fact,
pilot performance can seriously deteriorate within
15_minutes at 15,000 feet.
3. At cabin pressure altitudes above 15,000 feet,
the periphery of the visual field grays out to a point
where only central vision remains (tunnel vision). A
blue coloration (cyanosis) of the fingernails and lips
develops. The ability to take corrective and protective
action is lost in 20 to 30 minutes at 18,000 feet and
5_to 12 minutes at 20,000 feet, followed soon
thereafter by unconsciousness.
4. The altitude at which significant effects of
hypoxia occur can be lowered by a number of factors.
Carbon monoxide inhaled in smoking or from
exhaust fumes, lowered hemoglobin (anemia), and
certain medications can reduce the oxygen-carrying
capacity of the blood to the degree that the amount of
oxygen provided to body tissues will already be
equivalent to the oxygen provided to the tissues when
exposed to a cabin pressure altitude of several
thousand feet. Small amounts of alcohol and low
doses of certain drugs, such as antihistamines,
tranquilizers, sedatives and analgesics can, through
their depressant action, render the brain much more
susceptible to hypoxia. Extreme heat and cold, fever,
and anxiety increase the body's demand for oxygen,
and hence its susceptibility to hypoxia.
5. The effects of hypoxia are usually quite
difficult to recognize, especially when they occur
gradually. Since symptoms of hypoxia do not vary in
an individual, the ability to recognize hypoxia can be
greatly improved by experiencing and witnessing the
effects of hypoxia during an altitude chamber
“flight.” The FAA provides this opportunity through
aviation physiology training, which is conducted at
the FAA Civil Aeromedical Institute and at many
military facilities across the U.S. To attend the
Physiological Training Program at the Civil
Aeromedical Institute, Mike Monroney Aeronautical
Center, Oklahoma City, OK, contact by telephone
(405) 954-6212, or by writing Aerospace Medical
Education Division, AAM-400, CAMI, Mike
Monroney Aeronautical Center, P.O. Box 25082,
Oklahoma_City, OK 73125.
NOTE-
To attend the physiological training program at one of the
military installations having the training capability, an
application form and a fee must be submitted. Full
particulars about location, fees, scheduling procedures,
course content, individual requirements, etc., are con-
tained in the Physiological Training Application, Form
Number AC 3150-7, which is obtained by contacting the
accident prevention specialist or the office forms manager
in the nearest FAA office.
6. Hypoxia is prevented by heeding factors that
reduce tolerance to altitude, by enriching the inspired
air with oxygen from an appropriate oxygen system,
and by maintaining a comfortable, safe cabin
pressure altitude. For optimum protection, pilots are
encouraged to use supplemental oxygen above
10,000 feet during the day, and above 5,000 feet at
night. The CFRs require that at the minimum, flight
crew be provided with and use supplemental oxygen
after 30 minutes of exposure to cabin pressure
altitudes between 12,500 and 14,000 feet and
immediately on exposure to cabin pressure altitudes
above 14,000 feet. Every occupant of the aircraft
must be provided with supplemental oxygen at cabin
pressure altitudes above 15,000 feet.
b. Ear Block.
1. As the aircraft cabin pressure decreases
during ascent, the expanding air in the middle ear
pushes the eustachian tube open, and by escaping
down it to the nasal passages, equalizes in pressure
with the cabin pressure. But during descent, the pilot
must periodically open the eustachian tube to
equalize pressure. This can be accomplished by
swallowing, yawning, tensing muscles in the throat,
or if these do not work, by a combination of closing
AIM 2/14/08
