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Any deviation from the desired heading will be evident from the heading indicator. Immediate and smooth application of cyclic is used to return to the desired heading.
Small attitude and heading excursions when promptly corrected maintain good attitude control. After adjusting, scan the other performance instruments to verify the correction.
During cruise flight, if altitude cannot be maintained with cyclic, without exceeding airspeed changes of plus or minus 10 knots, power is used.
CLIMB
a) The climb is performed using the attitude-power-trim (APT) technique. Climb attitude is set using cyclic, then the power is adjusted by raising the collective to produce and maintain a 500 ft/min. rate of climb. As power is increased, the pedals must be adjusted to remain in co-ordinated flight.
b) During the climb, the heading, attitude, and airspeed are maintained by cyclic; rate of climb by collective; and trim by pedals. A lead of 10% of the rate of climb is generally accepted as the point to begin levelling off at the desired altitude. This amount can vary with the aircraft, rate of climb, and pilot technique.
c) Normal cruise is resumed using the attitude-power-trim technique. Cyclic to establish the attitude for the normal cruise airspeed, collective to set cruise power, and pedals to maintain co-ordinated flight.
DESCENTS
a) Descents are entered using the power-attitude-trim (PAT) technique. Lowering the collective to reduce the power to a setting that gives the desired rate of descent, usually 500 ft/min. Cyclic is adjusted to set the required attitude, and co-ordinated flight maintained by pedals.
b) Once established at a constant rate of descent, fine adjustments are made using collective pitch (power) changes.
c) Normal cruise is resumed using the power-attitude-trim technique once more. Prior to levelling off at the desired altitude, cruise power is applied to stop the downward movement through that altitude. A lead of 10% of the vertical rate of descent is normally required, i.e. 50 feet for 500 fpm.
d) The cruise attitude is set with cyclic, trim using pedals, and a scan started to establish level flight.
TURNS
An angle of bank of 15 to 20 degrees should not be exceeded for this exercise. Steep turns will be explained and practised for familiarization purposes.
To enter a turn, the cyclic is eased in the direction required. The initial bank is started with reference to the attitude indicator. When the desired angle of bank is reached, cyclic control pressure is held to maintain the angle of bank, but relaxed somewhat to prevent over bank. Easing the cyclic in the direction opposite to the turn will return the helicopter to straight and level flight. When doing this reference should be made to all available instruments.
Climbing and descending turns use the same technique, but usually the helicopter is established in the climb, or descent, before turning.
Turns to a specified heading should be made in the shortest direction referring to the heading indicator. Since the helicopter will continue to turn as long as the bank is held, roll out must be started before reaching the desired heading. The amount of lead used should be half the angle of bank. The technique is the same as above, except the cyclic is applied on reaching the lead heading.
The rate of 360 degrees in 2 minutes (3 degrees per second) is the standard rate turn. All timed turns are based on these criteria. The position of the sweep hand must be noted, or started, when the turn is initiated. For ease in timing, start the time when the sweep hand passes the 3, 6, 9, or 12 o’clock position. The standard rate of turn is maintained for the predetermined time and then the roll out is started.
Any turn with more than 20° of bank is considered a steep turn. Although they are seldom necessary or advisable in IMC, students will be familiarized with steep turns. This is to ensure they recognize and react quickly and smoothly to large changes in the helicopter’s attitude. The procedures are identical to any other turn manoeuvre, cyclic controlling rate of turn and attitude, collective controlling altitude and airspeed.
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直升机飞行训练手册 HELICOPTER FLIGHT TRAINING MANUAL(61)
