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Instrument Flying Handbook
Helicopter Attitude Instrument Flying
Straight-and-Level Flight

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Instrument Flying
Handbook

Preface

Table of Contents

Chapter 1. Human Factors
Chapter 2. Aerodynamic Factors
Chapter 3. Flight Instruments
Chapter 4. Section I
Airplane Attitude Instrument
Flying
Using Analog Instrumentation
Chapter 4. Section II
Airplane Attitude Instrument
Flying
Using an Electronic Flight
Display

Chapter 5. Section I
Airplane Basic
Flight Maneuvers
Using Analog Instrumentation
Chapter 5. Section II
Airplane Basic
Flight Maneuvers
Using an Electronic Flight
Display

Chapter 6. Helicopter
Attitude Instrument Flying

Chapter 7. Navigation Systems
Chapter 8. The National
Airspace System

Chapter 9. The Air Traffic
Control System

Chapter 10. IFR Flight
Chapter 11. Emergency
Operations

If the altitude is held constant, power determines the airspeed.
For example, at a constant altitude, cruising power results
in cruising airspeed. Any deviation from the cruising power
setting results in a change of airspeed. When power is added
to increase airspeed, the nose of the helicopter pitches up and
yaws to the right in a helicopter with a counterclockwise main
rotor blade rotation. [Figure 6-7] When power is reduced to
decrease airspeed, the rinse pitches down and yaws to the
left. [Figure 6-8] The yawing effect is most pronounced in
single-rotor helicopters, and is absent in helicopters with
counter-rotating rotors. To counteract the yawing tendency
of the helicopter, apply pedal trim during power changes.

To maintain a constant altitude and airspeed in level flight,
coordinate pitch attitude and power control. The relationship
between altitude and airspeed determines the need for a
change in power and/or pitch attitude. if the altitude is
constant and the airspeed is high or low, change the power to
obtain the desired airspeed. During the change in power, make
an accurate interpretation of the altimeter, then counteract
any deviation from the desired altitude by an appropriate
change of pitch attitude. if the altitude is low and the airspeed
is high, or vice versa, a change in pitch attitude alone may
return the helicopter to the proper altitude and airspeed. if
both airspeed and altitude are low, or if both are high, changes
in both power and pitch attitude are necessary.

To make power control easy when changing airspeed, it is
necessary to know the approximate power settings for the
various airspeeds at which the helicopter is flown. When the
airspeed is to he changed by any appreciable amount, adjust
the power so that it is over or under that setting necessary
to maintain the new airspeed. As the power approaches the
desired selling, include the manifold pressure in the cross-
check to determine when the proper adjustment has been
accomplished. As the airspeed is changing, adjust the pitch
attitude to maintain a constant altitude. A constant heading
should be maintained through out the change. As the desired
airspeed is approached, adjust power to the new cruising
power setting and further adjust pitch attitude to maintain
altitude. The instrument indications for straight-and-level
flight at normal cruise and during the transition from normal
cruise to slow cruise are illustrated in Figures 6-9 and 6-10.
After the airspeed stabilizes at slow cruise, the attitude
indicator shows an approximate level pitch attitude.

The altimeter is the primary pitch instrument during level
flight, whether flying at a constant airspeed or during a
change in airspeed. Altitude should not change during
airspeed transitions, and the heading indicator remains the
primary bank instrument. Whenever the airspeed is changed
by an appreciable amount, the manifold pressure gauge is
momentarily the primary instrument for power control.
When the airspeed approaches the desired reading, the
airspeed indicator again becomes the primary instrument
for power control.

Flight instrument indications in. straight-and-level flight with power increasing.
Figure 6-7. Flight instrument indications in. straight-and-level flight with power increasing.
 
6-8