GENERAL
When recovering from an unusual attitude or aircraft upset, the following three steps should be used as appropriate to the situation:
PUSH -Autopilot & autothrottles off -Forward pressure (or relaxed back pressure) on the yoke to keep angle of attack low (provides best acceleration & roll rate) -Trim as required
ROLL -Roll shortest direction to the horizon: toward bank angle indicator -Lead with rudder (more roll authority at high angle of attack)
PULL -Back pressure on yoke to return to level -To avoid ground contact: in and out of stick shaker, avoid stall
Stall Characteristics
Stall speeds are defined as the minimum steady flight speed at which a constant altitude can be maintained (or the minimum steady flight speed at which the angle of attach for maximum lift is attained). During initial stages of stall, local airflow separation results in buffeting, giving natural warning of an approach to a stall.
Initial buffet is caused by airflow separation. Stall warning is considered to be any warning readily identifiable by the pilot, either artificial (stick shaker) or initial buffet (stabilizer shake, aileron shake, or wing shake). Recovery from an approach to stall will be initiated at the earliest recognizable stall warning, initial buffet, or stick shaker.
Due to the effectiveness of the full span leading edge slats, the MD-80 does not exhibit the usual buffeting associated with stalling, nor is there a pronounced loss in lift after the maximum lift is reached. As a result, the usual cues which warn of impending stall and indicate the actual stall are not apparent to the pilot. In simple language, it is very difficult to tell the point where the 1G stall occurs. Therefore, the Supplementary Stall Recognition System (SSRS) has been devised to provide:
.
Unmistakable stall warning through stick shakers.
.
Positive stall recognition through the loud, urgent sound of a horn, accompanied by a blinking red STALL light on the glare shield. On aircraft equipped with the vocal warning system, the words, “STALL, STALL” will be heard.
.
If the stall is detected by both stall detection systems and the slats are fully extended, the control columns will be absolutely moved forward by a post stall Stick Pusher system.
Stall Recovery
Initiate recovery at first indication of a stall warning (buffet or stick shaker). The objective of the recovery action is to accelerate to the normal maneuvering airspeed with minimum altitude loss. This is accomplished by pushing the throttles to their furthest forward position, calling “MAX THROTTLES” and leveling the wings if in a turn. Smoothly adjust attitude as necessary to hold altitude (terrain avoidance), or manage altitude to minimum loss. If a pitch change is required, it should be smooth and gradual. At most configurations and gross weights, the aircraft will accelerate away from the stall warning without changing pitch attitude. Less altitude is lost and the recovery is simplified by not changing flap position.
The recovery procedures outlined above are for low altitude, minimum altitude loss situations with terrain a factor. If an indication of an impending stall is encountered at cruising altitude, it may be necessary to lower the pitch attitude below the horizon (10° nose low) to trade altitude for airspeed. Autopilot should be disengaged during recovery maneuver.
At intermediate altitude when terrain contact is not a factor, the pitch attitude should be lowered to approximately 5 degrees ANU while acceptable acceleration is achieved.
All recoveries from approaches to stalls are performed as if an actual stall has occurred. During stall recovery, smooth control inputs will help avoid or minimize altitude loss.
Gear and flaps should be retracted only after altitude loss is arrested, and the aircraft has accelerated to the maneuvering speed for the existing flap setting.
SIMULATOR TRAINING RECOVERY MANUEVERS
中國航空網 www.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：MD-80 Flight Manual 麥道80飛行手冊 2(62)
