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control varies from engine to engine. Malfunctions have occurred in-flight and on
the ground. The major challenge the flight crew faces when responding to this
malfunction is recognizing the condition and determining which engine has
malfunctioned. This condition can occur during any phase of flight.
October 31, 2006
777/787 Flight Crew Training Manual
Non-Normal Operations
Copyright © The Boeing Company. See title page for details.
FCT 777/787 Preliminary (TM) 8.7
Failure of engine or fuel control system components, or loss of thrust lever
position feedback has caused loss of engine thrust control. Control loss may not
be immediately evident since many engines fail to some fixed RPM or thrust lever
condition. This fixed RPM or thrust lever condition may be very near the
commanded thrust level and therefore difficult to recognize until the flight crew
attempts to change thrust with the thrust lever. Other engine responses include:
shutdown, operation at low RPM, or thrust at the last valid thrust lever setting (in
the case of a thrust lever feedback fault) depending on altitude or air/ground logic.
In all cases, the affected engine does not respond to thrust lever movement.
The Engine Limit/Surge/Stall NNC is written to include this malfunction. Since
recognition may be difficult, if a loss of engine control is suspected, the flight crew
should continue the takeoff or remain airborne until the Engine Limit/Surge/Stall
NNC can be accomplished. This helps with directional control and may preclude
an inadvertent shutdown of the wrong engine. In some conditions, such as during
low speed ground operations, immediate engine shutdown may be necessary to
maintain directional control.
Dual Engine Failure/Stall
Dual engine failure is a situation that demands prompt action regardless of altitude
or airspeed. Accomplish recall items and establish the appropriate airspeed to
immediately attempt a windmill restart. There is a higher probability that a
windmill start will succeed if the restart attempt is made as soon as possible (or
immediately after recognizing an engine failure) to take advantage of high engine
RPM. Use of higher airspeeds and altitudes below 30,000 feet improves the
probability of a restart. Loss of thrust at higher altitudes may require descent to a
lower altitude to improve windmill starting capability.
The inflight start envelope defines the region where windmill starts were
demonstrated during certification. It should be noted that this envelope does not
define the only areas where a windmill start may be successful. The DUAL
ENGINE FAIL/STALL NNC is written to ensure that flight crews take advantage
of the high RPM at engine failure regardless of altitude or airspeed.
A hung or stalled in-flight start is normally indicated by stagnant RPM and/or
increasing EGT. During start, engines may accelerate to idle slowly but action
should not be taken if RPM is increasing and EGT is not near or rapidly
approaching the limit.
Note: When electrical power is restored, do not confuse the establishment of
APU generator power with the establishment of engine generator power at
idle RPM and advance the thrust lever prematurely.
October 31, 2006
777/787 Flight Crew Training Manual
Non-Normal Operations
Copyright © The Boeing Company. See title page for details.
8.8 FCT 777/787 Preliminary (TM)
Engine Severe Damage Accompanied by High Vibration
Certain engine failures, such as fan blade separation can cause high levels of
airframe vibration. Although the airframe vibration may seem severe to the flight
crew, it is extremely unlikely that the vibration will damage the airplane structure
or critical systems. However, the vibration should be reduced as soon as possible
by reducing airspeed and descending. As altitude and airspeed change, the
airplane may transition through various levels of vibration. In general, vibration
levels decrease as airspeed decreases, however, at a given altitude vibration may
temporarily increase or decrease as airspeed changes.
If vibration remains unacceptable, descending to a lower altitude (terrain
permitting) allows a lower airspeed and normally lower vibration levels. Vibration
will likely become imperceptible as airspeed is further reduced during approach.
The impact of a vibrating environment on human performance is dependent on a
number of factors, including the orientation of the vibration relative to the body.
People working in a vibrating environment may find relief by leaning forward or
backward, standing, or otherwise changing their body position.
Once airframe vibration has been reduced to acceptable levels, the crew must
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787机组训练手册Flight Crew Training Manual 787(124)
