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Instrument Flying Handbook
Helicopter Attitude Instrument Flying
Turns

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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

Altimeter and turn indicator readings should remain constant
throughout the turn. The altimeter is primary for pitch control,
and the turn needle is primary for bank control. Manifold
pressure is primary for power control while the airspeed is
changing. As the airspeed approaches the new indication, the
airspeed indicator becomes primary for power control.

Two methods of changing airspeed in turns may be used.
In the first method, airspeed is changed after the turn is
established, in the second method, the airspeed change
is initiated simultaneously with the turn entry. The first
method is easier, but regardless of the method used, the rate
of cross-check must be increased as power is reduced. As
the helicopter decelerates, check the altimeter and VSI for
needed pitch changes, and the bank instruments for needed
bank changes. if the needle of the turn-and-slip indicator
shows a deviation from the desired deflection, change the
bank. Adjust pitch attitude to maintain altitude. When the
airspeed approaches that desired, the airspeed indicator
becomes primary for power control. Adjust the power to
maintain the desired airspeed. Use pedal trim to ensure the
maneuver is coordinated.

Until control technique is very smooth, frequently cross-
check the attitude indicator to keep from overcontrolling
and to provide approximate hank angles appropriate for the
changing airspeeds.

Compass Turns
The use of gyroscopic heading indicators makes heading
control very easy. However, if the heading indicator fails
or the helicopter is not equipped with one, use the magnetic
compass for heading reference. When making compass-only
turns, a pilot needs to adjust for the lead or lag created by
acceleration and deceleration errors so that the helicopter
tolls out on the desired heading. When turning to a heading
of north, the lead for the roll-out must include the number of
degrees of latitude plus the lead normally used in recovery
From turns. During a turn to a south heading, maintain the
turn until the compass passes south the number of degrees
of latitude, minus the normal roll-out lead. For example,
when turning from an easterly direction to north, where the
latitude is 30°, start the roll-out when the compass reads
37° (30° plus one-half the 15° angle of hank, or whatever
amount is appropriate for the rate of roll-out). When turning
from an easterly direction to south, start the roll-out when
the magnetic compass reads 203° (180° plus 30° minus one-
half the angle of bank). When making similar turns from a
westerly direction the appropriate points at which to begin
the roll-out would he 323° for a turn to north, and 157° for
a turn to south.

30° Bank Turn
A turn using 30° of bank is seldom necessary or advisable
in instrument meteorological conditions (IMC), and is
considered an unusual attitude in a helicopter. However, it
is an excellent maneuver to practice to increase the ability to
react quickly and smoothly to rapid changes of attitude. Even
though the entry and recovery techniques are the same as for
any other turn, it is more difficult to control pitch because
of the decrease in vertical lift as the bank increases. Also,
because of the decrease in vertical lift, there is a tendency
to lose altitude and/or airspeed. Therefore, to maintain a
constant altitude and airspeed, additional power is required.
Do not initiate a correction, however, until the instruments
indicate the need for one. During the maneuver, note the
need for a correction on the altimeter and VSI, check the
attitude indicator, and then make the necessary adjustments.
After making a change, check the altimeter and VSI again to
determine whether or not the correction was adequate.

Climbing and Descending Turns
For climbing and descending turns, the techniques described
previously for straight climbs, descents, and standard rate
turns are combined. For practice, simultaneously turn and
start the climb or descent. The primary and supporting
instruments for a stabilized constant airspeed left climbing
turn is illustrated in Figure 6-15. The level off from a
climbing or descending turn is the same as the level off from
a straight climb or descent. To return to straight-and-level
flight, stop the turn and then level off, or level off and then
stop the turn, or simultaneously level off and stop the turn.
During climbing and descending turns, keep the ball of the
turn indicator centered with pedal trim.

Common Errors During Turns

1. Failure to maintain desired turn rate

2. Failure to maintain altitude in level turns

3. Failure to maintain desired airspeed

4. Variation in the rate of entry and recovery

5. Failure to use proper lead in turns to a heading

6. Failure to properly compute time during timed turns

7. Failure to use proper leads and lags during the compass
turns

8. Improper use of power

9. Failure to use proper pedal trim

 
6-15