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 bank 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 rolls
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 bank 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 be 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 are illustrated in Figure 8-15 . 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
A O M
N 3 33
2 I
VERTICAL SPEED
THOUSAND FT PER MIN
UP
DOWN
.5
.5
33 30
2I
I5 I2
2 MIN TURN
DC ELEC
L R
30.0 29.9 29.8
I00 FEET
4 5 6
CALIBRATED
TO
20,000 FEET
ALT
20 20
I0 I0
I0 I0
20 20
TEST STBY PWR
IN Hg
ALg.
MANIFOLD
PRESS
E R
%RPM
Primary pitch Supporting pitch and bank
Primary bank Supporting pitch
Remains constant
Figure 6-12. Flight instrument indications for a stabilized left climbing turn at a constant airspeed.
Primary power
Figure 8-15. Flight instrument indications for a stabilized left climbing turn at a constant airspeed.
Unusual Attitudes
Any maneuver not required for normal helicopter instrument
flight is an unusual attitude and may be caused by any one
or combination of factors, such as turbulence, disorientation,
instrument failure, confusion, preoccupation with flight deck
duties, carelessness in cross-checking, errors in instrument
interpretation, or lack of proficiency in aircraft control. Due
to the instability characteristics of the helicopter, unusual
attitudes can be extremely critical. As soon as an unusual
attitude is detected, make a recovery to straight-and-level
flight as soon as possible with a minimum loss of altitude.
To recover from an unusual attitude, a pilot should correct
bank-and-pitch attitude and adjust power as necessary. All
components are changed almost simultaneously, with little
lead of one over the other. A pilot must be able to perform
this task with and without the attitude indicator. If the
helicopter is in a climbing or descending turn, adjust bank,
pitch, and power. The bank attitude should be corrected
by referring to the turn-and-slip indicator and attitude
indicator. Pitch attitude should be corrected by reference to
the altimeter, airspeed indicator, VSI, and attitude indicator.
Adjust power by referring to the airspeed indicator and
manifold pressure.
Since the displacement of the controls used in recovery from
unusual attitudes may be greater than those used for normal
flight, make careful adjustments as straight-and-level flight
is approached. Cross-check the other instruments closely to
avoid overcontrolling.
Common Errors During Unusual Attitude
Recoveries
1. Failure to make proper pitch correction
2. Failure to make proper bank correction
3. Failure to make proper power correction
4. Overcontrolling pitch and/or bank attitude
5. Overcontrolling power
6. Excessive loss of altitude
Emergencies
Emergencies during instrument flight are handled similarly
to those occurring during VFR flight. A thorough knowledge
of the helicopter and its systems, as well as good aeronautical
knowledge and judgment, is the best preparation for
emergency situations. Safe operations begin with preflight
planning and a thorough preflight inspection. Plan a route
of flight to include adequate landing sites in the event of an
emergency landing. Make sure all resources, such as maps,
publications, flashlights, and fire extinguishers, are readily
available for use in an emergency.
During any emergency, first fly the aircraft. This means
ensure the helicopter is under control, and determine
emergency landing sites. Then perform the emergency
checklist memory items, followed by items written in the
rotorcraft flight manual (RFM). When all these items are
under control, notify air traffic control (ATC). Declare any
emergency on the last assigned ATC frequency. If one was
not issued, transmit on the emergency frequency 121.5. Set
the transponder to the emergency squawk code 7700. This
code triggers an alarm or special indicator in radar facilities.
When experiencing most in-flight emergencies, such as low
fuel or complete electrical failure, land as soon as possible.
In the event of an electrical fire, turn off all nonessential
equipment and land immediately. Some essential electrical
instruments, such as the attitude indicator, may be required
for a safe landing. A navigation radio failure may not require
an immediate landing if the flight can continue safely. In
this case, land as soon as practical. ATC may be able to
provide vectors to a safe landing area. For specific details
on what to do during an emergency, refer to the RFM for
the helicopter.
Autorotations
Both straight-ahead and turning autorotations should be
practiced by reference to instruments. This training ensures
prompt corrective action to maintain positive aircraft control
in the event of an engine failure.
To enter autorotation, reduce collective pitch smoothly to
maintain a safe rotor RPM and apply pedal trim to keep the
ball of the turn-and-slip indicator centered. The pitch attitude
of the helicopter should be approximately level as shown by
the attitude indicator. The airspeed indicator is the primary
pitch instrument and should be adjusted to the recommended
autorotation speed. The heading indicator is primary for bank
in a straight-ahead autorotation. In a turning autorotation, a
standard rate turn should be maintained by reference to the
needle of the turn-and-slip indicator.
Common Errors During Autorotations
1. Uncoordinated entry due to improper pedal trim
2. Poor airspeed control due to improper pitch attitude
3. Poor heading control in straight-ahead autorotations
4. Failure to maintain proper rotor RPM
5. Failure to maintain a standard rate turn during turning
autorotations
Servo Failure
Most helicopters certified for single-pilot IFR flight are required
to have autopilots, which greatly reduces pilot workload. If an
autopilot servo fails, however, resume manual control of the
helicopter. The amount of workload increase depends on which
servo fails. If a cyclic servo fails, a pilot may want to land
immediately because the workload increases tremendously. If
an antitorque or collective servo fails, continuing to the next
suitable landing site might be possible.
Instrument Takeoff
The procedures and techniques described here should be
modified as necessary to conform to those set forth in the
operating instructions for the particular helicopter being
flown. During training, instrument takeoffs should not
be attempted except when receiving instruction from an
appropriately certificated, proficient flight instructor pilot.
Adjust the miniature aircraft in the attitude indicator, as
appropriate, for the aircraft being flown. After the helicopter
is aligned with the runway or takeoff pad, to prevent forward
movement of a helicopter equipped with a wheel-type landing
gear, set the parking brakes or apply the toe brakes. If the
parking brake is used, it must be unlocked after the takeoff
has been completed. Apply sufficient friction to the collective
pitch control to minimize overcontrolling and to prevent
creeping. Excessive friction should be avoided since it limits
collective pitch movement.
After checking all instruments for proper indications, start
the takeoff by applying collective pitch and a predetermined
power setting. Add power smoothly and steadily to gain
airspeed and altitude simultaneously and to prevent settling to
the ground. As power is applied and the helicopter becomes
airborne, use the antitorque pedals initially to maintain the
desired heading. At the same time, apply forward cyclic to
begin accelerating to climbing airspeed. During the initial
acceleration, the pitch attitude of the helicopter, as read on the
attitude indicator, should be one- to two-bar widths low. The
primary and supporting instruments after becoming airborne
are illustrated in Figure 8-16. As the airspeed increases to the
appropriate climb airspeed, adjust pitch gradually to climb
attitude. As climb airspeed is reached, reduce power to the
climb power setting and transition to a fully coordinated
straight climb.
During the initial climb out, minor heading corrections
should be made with pedals only until sufficient airspeed is
attained to transition to fully coordinated flight. Throughout
the instrument takeoff, instrument cross-check and
interpretations must be rapid and accurate and aircraft control
positive and smooth.
A O M
N 3 33
2 I
VERTICAL SPEED
THOUSAND FT PER MIN
UP
DOWN
.5
.5
30 24
2I
I2 6
2 MIN TURN
DC ELEC
L R
30.0 29.9 29.8
I00 FEET
4 5 6
CALIBRATED
TO
20,000 FEET
ALT
20 20
I0 I0
I0 I0
20 20
TEST STBY PWR
IN Hg
ALg.
MANIFOLD
PRESS
E R
%RPM
Supporting pitch
Primary pitch and supporting bank
Supporting bank Supporting pitch
Supporting pitch
Primary bank
Remains constant
Figure 6-13. Flight instrument indications during an instrument takeoff. Figure 8-16. Flight instrument indications during an instrument takeoff.
Common Errors During Instrument Takeoffs
1. Failure to maintain heading
2. Overcontrolling pedals
3. Failure to use required power
4. Failure to adjust pitch attitude as climbing airspeed
is reached
Changing Technology
Advances in technology have brought about changes in
the instrumentation found in all types of aircraft, including
helicopters. Electronic displays commonly referred to as
“glass cockpits” are becoming more common. Primary flight
displays (PFDs) and multi-function displays (MFDs) are
changing not only what information is available to a pilot
but also how that information is displayed.
Illustrations of technological advancements in instrumentation
are described as follows. In Figure 8-17, a typical PFD
depicts an aircraft flying straight-and-level at 3,000 feet and
100 knots. Figure 8-18 illustrates a nose-low pitch attitude in
a right turn. MFDs can be configured to provide navigation
information, such as the moving map in Figure 8-19 or
information pertaining to aircraft systems as in Figure 8-20.
XPDR 5537 IDNT LCL23:00:34
VOR 1
270°
TAS 100KT
OAT 7°C
NAV1 108.00 113.00
NAV2 108.00 110.60
134.000 118.000 COM1
123.800 118.000 COM2
WPT _ _ _ _ _ _ DIS _ _ ._ NM DTK _ _ _° TRK 360°
PFD depicts flying straight and level
Figure 8-17. PFD indications during straight-and-level flight.
XPDR 5537 IDNT LCL23:00:34
VOR 1
270°
-500
TAS 107KT
OAT 7°C
NAV1 108.00 113.00
NAV2 108.00 110.60
134.000 118.000 COM1
123.800 118.000 COM2
WPT _ _ _ _ _ _ DIS _ _ ._ NM DTK _ _ _° TRK 360°
-125
-250
-375
Pitch attitude nose-low right turn
Figure 8-18. PFD indications during a nose-low pitch attitude in a right turn.
XPDR 5537 IDNT LCL23:00:34
VOR 1
270°
T AS 100KT
OA T 7°C
13.7
23.0
NA V1 108.00 113.00
NA V2 108.00 110.60
134.000 118.000 COM1
123.800 118.000 COM2
WPT _ _ _ _ _ _ DIS _ _ . _ NM DTK _ _ _°T TRK 360°T
MFD provide navigation information - moving map
Figure 8-19. MFD display of a moving map.
Figure 8-20. MFD display of aircraft systems.