直升机飞行手册Rotorcraft flying handbook

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Avionic

Bus

Avionics Relay

On

Off

Avionics Master

Switch

Lights

Panel

Position

Beacon

Trim

Instr

Lndg Lt

Radio

Xpdr

Clutch

Ammeter

Mag Switch

Left

Magneto

Right

Magneto

Starter

Relay

Engine

Starter

Bus Bar

Battery

Relay

Battery

Battery

Switch

Starter

Switch

M/R Gearbox

Press Switch

Release

Hold

Engage

Clutch

Switch

Alternator

Alternator

Switch

Alternator

Control Unit

Clutch Actuator

(Internal Limit Switches

Shown in Full

Disengage Position)

24V

– +

F1 F2

–

+

Starting

Vibrator

R

R

Both

L L

Off

Ret

Adv

Adv

G

(Optional Avionics)

Figure 5-12. An electrical system scematic like this sample is

included in most POHs. Notice that the various bus bar

accessories are protected by circuit breakers. However, you

should still make sure all electrical equipment is turned off

before you start the engine. This protects sensitive components, particularly the radios, from damage which may be

caused by random voltages generated during the starting

process.

Filter

To Carb

Carb Heat

Collector

Manifold

Pipe

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Door

Filter

To Carb

Carb Heat

Collector

Manifold

Pipe

Door

Heated Air

Carb Heat Off

Carb Heat On

Figure 5-11. When you turn the carburetor heat ON, normal

air flow is blocked, and heated air from an alternate source

flows through the filter to the carburetor.

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incorporated to prevent excessive voltage, which may

damage the electrical components. The bus bar serves

to distribute the current to the various electrical components of the helicopter.

A battery is mainly used for starting the engine. In

addition, it permits limited operation of electrical

components, such as radios and lights, without the

engine running. The battery is also a valuable source

of standby or emergency electrical power in the event

of alternator or generator failure.

An ammeter or loadmeter is used to monitor the

electrical current within the system. The ammeter

reflects current flowing to and from the battery. A

charging ammeter indicates that the battery is being

charged. This is normal after an engine start since

the battery power used in starting is being replaced.

After the battery is charged, the ammeter should stabilize near zero since the alternator or generator is

supplying the electrical needs of the system. A discharging ammeter means the electrical load is

exceeding the output of the alternator or generator,

and the battery is helping to supply electrical power.

This may mean the alternator or generator is malfunctioning, or the electrical load is excessive. A

loadmeter displays the load placed on the alternator

or generator by the electrical equipment. The RFM

for a particular helicopter shows the normal load to

expect. Loss of the alternator or generator causes the

loadmeter to indicate zero.

Electrical switches are used to select electrical components. Power may be supplied directly to the component

or to a relay, which in turn provides power to the

component. Relays are used when high current and/or

heavy electrical cables are required for a particular component, which may exceed the capacity of the switch.

Circuit breakers or fuses are used to protect various

electrical components from overload. A circuit breaker

pops out when its respective component is overloaded.

The circuit breaker may be reset by pushing it back in,

unless a short or the overload still exists. In this case,

the circuit breaker continues to pop, indicating an electrical malfunction. A fuse simply burns out when it is

overloaded and needs to be replaced. Manufacturers

usually provide a holder for spare fuses in the event one

has to be replaced in flight. Caution lights on the instrument panel may be installed to show the

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malfunction of

an electrical component.

HYDRAULICS

Most helicopters, other than smaller piston powered

helicopters, incorporate the use of hydraulic actuators

to overcome high control forces. [Figure 5-13] A typical hydraulic system consists of actuators, also called

Pressure

Return

Supply

Scupper

Drain

Vent Reservoir

Pump

Pressure

Regulator

Valve

Quick

Disconnects

Filter

Solenoid

Valve

Servo

Actuator,

Lateral

Cyclic

Servo

Actuator,

Fore and

Aft

Cyclic

Servo

Actuator,

Collective

Pilot

Input

Rotor

Control

Figure 5-13. A typical hydraulic system for helicopters in the light to medium range is shown here.

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igation capabilities, such as VOR, ILS, and GPS

intercept and tracking, which is especially useful in

IFR conditions. The most advanced autopilots can

fly an instrument approach to a hover without any

additional pilot input once the initial functions have

been selected.

The autopilot system consists of electric actuators or

servos connected to the flight controls. The number and

location of these servos depends on the type of system

installed. A two-axis autopilot controls the helicopter

in pitch and roll; one servo controls fore and aft cyclic,

and another controls left and right cyclic. A three-axis

autopilot has an additional servo connected to the antitorque pedals and controls the helicopter in yaw. A

four-axis system uses a fourth servo which controls the

collective. These servos move the respective flight controls when they receive control commands from a central computer. This computer receives data input from

the flight instruments for attitude reference and from

the navigation equipment for navigation and tracking

reference. An autopilot has a control panel in the cockpit that allows you to select the desired functions, as

well as engage the autopilot.

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For safety purposes, an automatic disengage feature is

usually included which automatically disconnects the

autopilot in heavy turbulence or when extreme flight

attitudes are reached. Even though all autopilots can be

overridden by the pilot, there is also an autopilot disengage button located on the cyclic or collective which

allows you to completely disengage the autopilot without removing your hands from the controls. Because

autopilot systems and installations differ from one helicopter to another, it is very important that you refer to

the autopilot operating procedures located in the

Rotorcraft Flight Manual.

ENVIRONMENTAL SYSTEMS

Heating and cooling for the helicopter cabin can be

provided in different ways. The simplest form of cooling is ram air cooling. Air ducts in the front or sides of

the helicopter are opened or closed by the pilot to let

ram air into the cabin. This system is limited as it

requires forward airspeed to provide airflow and also

servos, on each flight control, a pump which is usually

driven by the main rotor gearbox, and a reservoir to

store the hydraulic fluid. A switch in the cockpit can

turn the system off, although it is left on under normal

conditions. A pressure indicator in the cockpit may also

be installed to monitor the system.

When you make a control input, the servo is activated

and provides an assisting force to move the respective

flight control, thus lightening the force required by the

pilot. These boosted flight controls ease pilot workload

and fatigue. In the event of hydraulic system failure,

you are still able to control the helicopter, but the control forces will be very heavy.

In those helicopters where the control forces are so

high that they cannot be moved without hydraulic

assistance, two or more independent hydraulic systems

may be installed. Some helicopters use hydraulic accumulators to store pressure, which can be used for a

short period of time in an emergency if the hydraulic

pump fails. This gives you enough time to land the helicopter with normal control

STABILITY AUGMENTATIONS SYSTEMS

Some helicopters incorporate stability augmentations

systems (SAS) to aid in stabilizing the helicopter in

flight and in a hover. The simplest of these systems is a

force trim system, which uses a magnetic clutch and

springs to hold the cyclic control in the position where

it was released. More advanced systems use electric

servos that actually move the flight controls. These

servos receive control commands from a computer that

senses helicopter attitude. Other inputs, such as

heading, speed, altitude, and navigation information

may be supplied to the computer to form a complete

autopilot system. The SAS may be overridden or

disconnected by the pilot at any time.

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Stability augmentation systems reduce pilot workload

by improving basic aircraft control harmony and

decreasing disturbances. These systems are very useful

when you are required to perform other duties, such as

sling loading and search and rescue operations.

AUTOPILOT

Helicopter autopilot systems are similar to stability

augmentations systems except they have additional

features. An autopilot can actually fly the helicopter

and perform certain functions selected by the pilot.

These functions depend on the type of autopilot and

systems installed in the helicopter.

The most common functions are altitude and heading

hold. Some more advanced systems include a vertical

speed or indicated airspeed (IAS) hold mode, where a

constant rate of climb/descent or indicated airspeed is

maintained by the autopilot. Some autopilots have nav-

VOR—Ground-based navigation system consisting of very high frequency omnidirectional range (VOR) stations which provide course

guidance.

ILS (Instrument Landing System)—A precision instrument approach

system, which normally consists of the following electronic components

and visual aids: localizer, glide slope, outer marker, and approach

lights.

GPS (Global Positioning System)—A satellite-based radio positioning,

navigation, and time-transfer system.

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.

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depends on the temperature of the outside air. Air conditioning provides better cooling but it is more complex and weighs more than a ram air system.

Piston powered helicopters use a heat exchanger

shroud around the exhaust manifold to provide cabin

heat. Outside air is piped to the shroud and the hot

exhaust manifold heats the air, which is then blown

into the cockpit. This warm air is heated by the exhaust

manifold but is not exhaust gas. Turbine helicopters

use a bleed air system for heat. Bleed air is hot, compressed, discharge air from the engine compressor. Hot

air is ducted from the compressor to the helicopter

cabin through a pilot-controlled, bleed air valve.

ANTI-ICING SYSTEMS

Most anti-icing equipment installed on small helicopters

is limited to engine intake anti-ice and pitot heat systems.

The anti-icing system found on most turbine-powered

helicopters uses engine bleed air. The bleed air flows

through the inlet guide vanes to prevent ice formation on

the hollow vanes. A pilot-controlled, electrically operated

valve on the compressor controls the air flow. The pitot

heat system uses an electrical element to heat the pitot

tube, thus melting or preventing ice formation.

Airframe and rotor anti-icing may be found on some

larger helicopters, but it is not common due to the

complexity, expense, and weight of such systems. The

leading edges of rotors may be heated with bleed air or

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electrical elements to prevent ice formation. Balance and

control problems might arise if ice is allowed to form

unevenly on the blades. Research is being done on

lightweight ice-phobic (anti-icing) materials or coatings.

These materials placed in strategic areas could significantly reduce ice formation and improve performance.

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6-1

Title 14 of the Code of Federal Regulations (14 CFR)

part 91 requires that pilots comply with the operating

limitations specified in approved rotorcraft flight manuals, markings, and placards. Originally, flight manuals

were often characterized by a lack of essential information and followed whatever format and content the

manufacturer felt was appropriate. This changed with

the acceptance of the General Aviation Manufacturers

Association’s (GAMA) Specification for Pilot’s

Operating Handbook, which established a standardized

format for all general aviation airplane and rotorcraft

flight manuals. The term “Pilot’s Operating Handbook

(POH)” is often used in place of “Rotorcraft Flight

Manual (RFM).” However, if “Pilot’s Operating

Handbook” is used as the main title instead of “Rotorcraft

Flight Manual,” a statement must be included on the title

page indicating that the document is the FAA-Approved

Rotorcraft Flight Manual. [Figure 6-1]

Besides the preliminary pages, an FAA-Approved

Rotorcraft Flight Manual may contain as many as ten sections. These sections are: General Information; Operating

Limitations; Emergency Procedures; Normal Procedures;

Performance; Weight and Balance; Aircraft and Systems

Description; Handling, Servicing, and Maintenance; and

Supplements. Manufacturers have the option of including

a tenth section on Safety and Operational Tips and an

alphabetical index at the end of the handbook.

PRELIMINARY PAGES

While rotorcraft flight manuals may appear similar for

the same make and model of aircraft, each flight man-

ual is unique since it contains specific information

about a particular aircraft, such as the equipment

installed, and weight and balance information.

Therefore, manufacturers are required to include the

serial number and registration on the title page to identify the aircraft to which the flight manual belongs. If a

flight manual does not indicate a specific aircraft registration and serial number, it is limited to general study

purposes only.

Most manufacturers include a table of contents, which

identifies the order of the entire manual by section number and title. Usually, each section also contains its own

table of contents. Page numbers reflect the section you

are reading, 1-1, 2-1, 3-1, and so on. If the flight manual

is published in looseleaf form, each section is usually

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marked with a divider tab indicating the section number

or title, or both. The Emergency Procedures section may

have a red tab for quick identification and reference.

GENERAL INFORMATION

The General Information section provides the basic

descriptive information on the rotorcraft and the powerplant. In some manuals there is a three-view drawing of

the rotorcraft that provides the dimensions of various

components, including the overall length and width, and

the diameter of the rotor systems. This is a good place to

quickly familiarize yourself with the aircraft.

You can find definitions, abbreviations, explanations of

symbology, and some of the terminology used in the

manual at the end of this section. At the option of the

manufacturer, metric and other conversion tables may

also be included.

OPERATING LIMITATIONS

The Operating Limitations section contains only those

limitations required by regulation or that are necessary

for the safe operation of the rotorcraft, powerplant, systems, and equipment. It includes operating limitations,

instrument markings, color coding, and basic placards.

Some of the areas included are: airspeed, altitude, rotor,

and powerplant limitations, including fuel and oil

requirements; weight and loading distribution; and

flight limitations.

AIRSPEED LIMITATIONS

Airspeed limitations are shown on the airspeed indicator by color coding and on placards or graphs in the

Figure 6-1. The Rotorcraft Flight Manual is a regulatory document in terms of the maneuvers, procedures, and operating

limitations described therein.

6-2

aircraft. A red line on the airspeed indicator shows the

airspeed limit beyond which structural damage could

occur. This is called the never exceed speed, or VNE.

The normal operating speed range is depicted by a green

arc. A blue line is sometimes added to show the maximum safe autorotation speed. [Figure 6-2]

ALTITUDE LIMITATIONS

If the rotorcraft has a maximum operating density altitude, it is indicated in this section of the flight manual.

Sometimes the maximum altitude varies based on different gross weights.

ROTOR LIMITATIONS

Low rotor r.p.m. does not produce sufficient lift, and

high r.p.m. may cause structural damage, therefore

rotor r.p.m. limitations have minimum and maximum

values. A green arc depicts the normal operating range

with red lines showing the minimum and maximum

limits. [Figure 6-3]

There are two different rotor r.p.m. limitations: power-on

and power-off. Power-on limitations apply anytime the

engine is turning the rotor and is depicted by a fairly narrow green band. A yellow arc may be included to show a

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transition range, which means that operation within this

range is limited. Power-off limitations apply anytime the

engine is not turning the rotor, such as when in an autorotation. In this case, the green arc is wider than the poweron arc, indicating a larger operating range.

POWERPLANT LIMITATIONS

The Powerplant Limitations area describes operating

limitations on the rotorcraft’s engine including such

items as r.p.m. range, power limitations, operating temperatures, and fuel and oil requirements. Most turbine

engines and some reciprocating engines have a maximum power and a maximum continuous power rating.

The “maximum power” rating is the maximum power

the engine can generate and is usually limited by time.

The maximum power range is depicted by a yellow arc

on the engine power instruments, with a red line indicating the maximum power that must not be exceeded.

“Maximum continuous power” is the maximum power

the engine can generate continually, and is depicted by

a green arc. [Figure 6-4]

Like on a torque and turbine outlet temperature gauge,

the red line on a manifold pressure gauge indicates the

maximum amount of power. A yellow arc on the gauge

warns of pressures approaching the limit of rated

power. A placard near the gauge lists the maximum

readings for specific conditions. [Figure 6-5]

WEIGHT AND LOADING DISTRIBUTION

The Weight and Loading Distribution area contains the

maximum certificated weights, as well as the center of

gravity (CG) range. The location of the reference datum

used in balance computations should also be included in

this section. Weight and balance computations are not

provided here, but rather in the Weight and Balance

Section of the FAA-Approved Rotocraft Flight Manual.

150 20

40

60

80

100

120

AIRSPEED

KNOTS

17

14

12

8

6

4

MPH

X 10

Figure 6-2. Typical airspeed indicator limitations and markings.

ROTOR

ENGINE

RPM

100

5

l0

l

2

3

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4

5

l5

20

25

30

35

40

Figure 6-3. Markings on a typical dual-needle tachometer in a

reciprocating-engine helicopter. The outer band shows the

limits of the superimposed needles when the engine is turning the rotor. The inner band indicates the power-off limits.

40

50

60 70

80

90

100

110

120

0

10

20

30

TORQUE

PERCENT

1

2

3

4

5

6

7

8

9

TURB

OUT

TEMP

°C X 100

Figure 6-4. Torque and turbine outlet temperature (TOT)

gauges are commonly used with turbine-powered aircraft.

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FLIGHT LIMITATIONS

This area lists any maneuvers which are prohibited,

such as acrobatic flight or flight into known icing conditions. If the rotorcraft can only be flown in VFR

conditions, it will be noted in this area. Also included

are the minimum crew requirements, and the pilot seat

location, if applicable, where solo flights must be conducted.

PLACARDS

All rotorcraft generally have one or more placards displayed that have a direct and important bearing on the

safe operation of the rotorcraft. These placards are

located in a conspicuous place within the cabin and

normally appear in the Limitations Section. Since VNE

changes with altitude, this placard can be found in all

helicopters. [Figure 6-6]

EMERGENCY PROCEDURES

Concise checklists describing the recommended procedures and airspeeds for coping with various types of

emergencies or critical situations can be found in this

section. Some of the emergencies covered include:

engine failure in a hover and at altitude, tail rotor failures, fires, and systems failures. The procedures for

restarting an engine and for ditching in the water might

also be included.

Manufacturers may first show the emergencies checklists in an abbreviated form with the order of

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items

reflecting the sequence of action. This is followed by

amplified checklists providing additional information

to help you understand the procedure. To be prepared

for an abnormal or emergency situation, memorize the

first steps of each checklist, if not all the steps. If time

permits, you can then refer to the checklist to make sure

all items have been covered. (For more information on

emergencies, refer to Chapter 11—Helicopter Emergencies

and Chapter 21—Gyroplane Emergencies.)

Manufacturers also are encouraged to include an optional

area titled “Abnormal Procedures,” which describes recommended procedures for handling malfunctions that are

not considered to be emergencies. This information

would most likely be found in larger helicopters.

NORMAL PROCEDURES

The Normal Procedures is the section you will probably use the most. It usually begins with a listing of the

airspeeds, which may enhance the safety of normal

operations. It is a good idea to memorize the airspeeds

that are used for normal flight operations. The next part

of the section includes several checklists, which take

you through the preflight inspection, before starting

procedure, how to start the engine, rotor engagement,

ground checks, takeoff, approach, landing, and shutdown. Some manufacturers also include the procedures

for practice autorotations. To avoid skipping an important step, you should always use a checklist when one is

available. (More information on maneuvers can be

found in Chapter 9—Basic Maneuvers, Chapter 10—

Advanced Maneuvers, and Chapter 20—Gyroplane

Flight Operations.)

PERFORMANCE

The Performance Section contains all the information

required by the regulations, and any additional performance information the manufacturer feels may

enhance your ability to safely operate the rotorcraft.

l5

l0

20

25

35 5

30

MANIFOLD

PRESSURE

INCHES

OF MERCURY

Figure 6-5. A manifold pressure gauge is commonly used

with piston-powered aircraft.

Press Alt.

1,000 FT

F OAT 8 4 6 8 10 12 14

0 109 109 105 84 61 -- --

109 109 109 109 98 77 58