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continuous stick shaker activation accompanied by one or more of the following:
• buffeting which could be heavy at times
• lack of pitch authority and/or roll control
• inability to arrest descent rate.
October 31, 2006
777/787 Flight Crew Training Manual
Maneuvers
Copyright © The Boeing Company. See title page for details.
7.28 FCT 777/787 Preliminary (TM)
If the airplane is stalled, recovery from the stall must be accomplished first by
applying and maintaining nose down elevator until stall recovery is complete and
stick shaker activation ceases. Under certain conditions, it may be necessary to
reduce some thrust in order to prevent the angle of attack from continuing to
increase. Once stall recovery is complete, upset recovery actions may be taken and
thrust reapplied as needed.
Nose High, Wings Level
In a situation where the airplane pitch attitude is unintentionally more than 25
degrees nose high and increasing, the airspeed is decreasing rapidly. As airspeed
decreases, the pilot's ability to maneuver the airplane also decreases. If the
stabilizer trim setting is nose up, as for slow-speed flight, it partially reduces the
nose-down authority of the elevator. Further complicating this situation, as the
airspeed decreases, the pilot could intuitively make a large thrust increase. This
causes an additional pitch up. At full thrust settings and very low airspeeds, the
elevator, working in opposition to the stabilizer, has limited control to reduce the
pitch attitude.
In this situation the pilot should trade altitude for airspeed, and maneuver the
airplane's flight path back toward the horizon. This is accomplished by the input
of up to full nose-down elevator and the use of some nose-down stabilizer trim.
These actions should provide sufficient elevator control power to produce a
nose-down pitch rate. It may be difficult to know how much stabilizer trim to use,
and care must be taken to avoid using too much trim. Pilots should not fly the
airplane using stabilizer trim, and should stop trimming nose down when they feel
the g force on the airplane lessen or the required elevator force lessen. This use of
stabilizer trim may correct an out-of-trim airplane and solve a less-critical
problem before the pilot must apply further recovery measures. Because a large
nose-down pitch rate results in a condition of less than 1 g, at this point the pitch
rate should be controlled by modifying control inputs to maintain between 0 to 1
g. If altitude permits, flight tests have determined that an effective way to achieve
a nose-down pitch rate is to reduce some thrust.
If normal pitch control inputs do not stop an increasing pitch rate, rolling the
airplane to a bank angle that starts the nose down should work. Bank angles of
about 45 degrees, up to a maximum of 60 degrees, could be needed. Unloading the
wing by maintaining continuous nose-down elevator pressure keeps the wing
angle of attack as low as possible, making the normal roll controls as effective as
possible. With airspeed as low as stick shaker onset, normal roll controls - up to
full deflection of ailerons and spoilers - may be used. The rolling maneuver
changes the pitch rate into a turning maneuver, allowing the pitch to decrease.
Finally, if normal pitch control then roll control is ineffective, careful rudder input
in the direction of the desired roll may be required to induce a rolling maneuver
for recovery.
October 31, 2006
777/787 Flight Crew Training Manual
Maneuvers
Copyright © The Boeing Company. See title page for details.
FCT 777/787 Preliminary (TM) 7.29
Only a small amount of rudder is needed. Too much rudder applied too quickly or
held too long may result in loss of lateral and directional control. Because of the
low energy condition, pilots should exercise caution when applying rudder.
The reduced pitch attitude allows airspeed to increase, thereby improving elevator
and aileron control effectiveness. After the pitch attitude and airspeed return to a
desired range the pilot can reduce angle of bank with normal lateral flight controls
and return the airplane to normal flight.
Nose Low, Wings Level
In a situation where the airplane pitch attitude is unintentionally more than 10
degrees nose low and going lower, the airspeed is increasing rapidly. A pilot
would likely reduce thrust and extend the speedbrakes. Thrust reduction causes an
additional nose-down pitching moment. Speedbrake extension causes a nose-up
pitching moment, an increase in drag, and a decrease in lift for the same angle of
attack. At airspeeds well above VMO/MMO, the ability to command a nose-up
pitch rate with elevator may be reduced because of the extreme aerodynamic loads
　
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本文鏈接地址：787機組訓練手冊Flight Crew Training Manual 787(117)