Helicopter Instrument Straight-and-Level Flight[PDF]
Straight-and-level unaccelerated flight is controlling pitch, bank and power of the helicopter to maintain a constant altitude, heading, airspeed and pedal trim.
For straight-and-level flight:
- Altimeter is primary instrument for pitch
- Heading indicator is primary instrument for bank
- Torque/manifold pressure is primary instrument for power
- Attitude indicator is supporting instrument for pitch and bank
- Variometer is supporting instrument for pitch
- Turn-and-slip indicator is supporting instrument for bank control
Straight means constant heading, level means constant altitude and unaccelerated means constant airspeed. Straight-and-level unaccelerated flight in IFR is accomplished by keeping the desired heading, altitude and airspeed by reference to the instruments.
Pitch attitude of a helicopter should be established to maintain the desired altitude and airspeed reference to the pitch instruments.
Use the attitude indicator to establish the required pitch to reach target altitude. When altitude has been established, cross-check other pitch instruments to maintain constant altitude.
- When losing altitude, raise the pitch attitude and adjust power as necessary. When gaining altitude, lower the pitch attitude and adjust power as necessary.
- If the airspeed increases, the nose is too low and should be raised. If the airspeed decreases, the nose is too high and should be lowered.
- After making a correction, cross-check the other pitch instruments to determine whether the pitch attitude change is sufficient.
The Bank attitude of a helicopter should be established to maintain the desired heading reference to the bank instruments.
Use the attitude indicator and the turn indicator to establish the required bank to reach target heading. When heading has been established, cross-check the bank instruments to maintain constant heading.
- To maintain a straight course, keep the miniature aircraft and the horizon bar of the attitude indicator in a position which ensures no deviation in the heading indicator.
- If a turn is noticed, apply opposite cyclic until the heading indicator indicates the desired heading, simultaneously ensuring the ball is centered.
To produce straight-and-level flight, the cross-check of the pitch-and-bank instruments should be combined with the power control instruments. With a constant power setting, a normal cross-check should be satisfactory. When changing power, the speed of the cross-check must be increased to cover the pitch and bank instruments adequately. This is necessary to counteract any deviations immediately.
- At constant altitude, cruising airspeed maintained with cruising power results in level flight.
- If a pilot increases the power setting and holds the airspeed constant, the helicopter climbs.
- If the pilot decreases power and holds the airspeed constant, the helicopter descends.
- 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.
- Instrument Flying Handbook (FAA-H-8083-15B)
- VID 522050- Creation
DATE OF SUBMISSION
- 12:49, 23 February 2021
- This documentation is copyrighted as part of the intellectual property of the International Virtual Aviation Organisation.
- The content of this documentation is intended for aviation simulation only and must not be used for real aviation operations.