旋翼机飞行手册 ROTORCRAFT FLYING HANDBOOK

时间：2011-04-05 11:32来源：蓝天飞行翻译 作者：航空 点击：次

To view this page ensure that Adobe Flash Player version 9.0.124 or greater is installed.

Just prior to touchdown, place the helicopter in a level attitude with the cyclic, and maintain heading with the antitorque pedals. Use the cyclic to keep the heading and ground track identical (position 3). Allow the helicopter to descend gently to the surface in a straight-and-level attitude, cushioning the landing with the collective. After surface contact, move the cyclic slightly forward to ensure clearance between the tailboom and the rotor disc. You should also use the cyclic to maintain the surface track. (position 4). You normally hold the collective stationary until the helicopter stops; however, if you want more braking action, you can lower the collective slightly. Keep in mind that due to the increased ground friction when you lower the collective, the helicopter’s nose might pitch forward. Exercise caution not to correct this pitching movement with aft cyclic since this movement could result in the rotor making contact with the tailboom. During the landing, maintain normal r.p.m. with the throttle and directional control with the antitorque pedals.
For wheeled helicopters, use the same technique except after landing, lower the collective, neutralize the controls, and apply the brakes, as necessary, to slow the helicopter. Do not use aft cyclic when bringing the helicopter to a stop.

COMMON ERRORS
1 Assuming excessive nose-high attitude to slow the helicopter near the surface.
2 Insufficient collective and throttle to cushion landing.
3 Failing to add proper antitorque pedal as collective is added to cushion landing, resulting in a touchdown while the helicopter is moving sideward.
4 Failing to maintain a speed that takes advantage of effective translational lift.

1 Touching down at an excessive groundspeed for the existing conditions. (Some helicopters have maximum touchdown groundspeeds.)
2 Failing to touch down in a level attitude.
3 Failing to maintain proper r.p.m. during and after touchdown.
4 Poor directional control during touchdown.

SLOPE OPERATIONS
Prior to conducting any slope operations, you should be thoroughly familiar with the characteristics of dynamic rollover and mast bumping, which are discussed in Chapter 11—Helicopter Emergencies. The approach to a slope is similar to the approach to any other landing area. During slope operations, make allowances for wind, barriers, and forced landing sites in case of engine failure. Since the slope may constitute an obstruction to wind passage, you should anticipate turbulence and downdrafts.
SLOPE LANDING
You usually land a helicopter across the slope rather than with the slope. Landing with the helicopter facing down the slope or downhill is not recommended because of the possibility of striking the tail rotor on the surface.
TECHNIQUE
Refer to figure 10-6. At the termination of the approach, move the helicopter slowly toward the slope, being careful not to turn the tail upslope. Position the helicopter across the slope at a stabilized hover headed into the wind over the spot of intended landing (frame 1). Downward pressure on the collective starts the helicopter descending. As the upslope skid touches the ground, hesitate momentarily in a level attitude, then apply lateral cyclic in the direction of the slope (frame 2). This holds the skid against the slope while you continue lowering the downslope skid with the collective. As you lower the collective, continue to move the cyclic toward the slope to maintain a fixed position (frame 3). The slope must be shallow enough so you can hold the helicopter against it with the cyclic during the entire landing. A slope of 5° is considered maximum for normal operation of most helicopters.

直升机翻译 www.aviation.cn
本文链接地址：旋翼机飞行手册 ROTORCRAFT FLYING HANDBOOK