787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Engines, APU -
Engine System Description
Copyright © The Boeing Company. See title page for details.
7.20.8 D615Z003-TBC
Delayed engine response due to thrust ramping may be noticed by flight crews
during conditions of high altitude and high ambient temperature that necessitate
maximum takeoff thrust settings. Thrust ramping is only active on the ground with
the EEC in normal mode.
Note: Due to thrust ramping, maximum takeoff thrust may not be available until
reaching 65 KIAS.
Thrust Control Malfunction Accommodation
Thrust Control Malfunction Accommodation is an EEC function that provides
protection against idle thrust asymmetry conditions while on the ground.
The EEC commands shutdown of the affected engine when the:
• airplane is on the ground, and
• thrust lever is at idle, and
• engine is above idle speed and not decelerating normally
The EICAS caution message ENG FAIL (L or R) is displayed with an aural beeper
once the engine falls below idle speed.
Thrust Asymmetry Protection (TAP)
Thrust Asymmetry Protection only functions when there is a large thrust
asymmetry during takeoff or go-around. TAP automatically reduces thrust on the
operating engine when there is a large thrust to weight ratio, but does so while
maintaining the required climb performance. The TAP function applied during an
engine out takeoff provides directional control protection but only when airspeed
drops below the normal operating speeds. The TAP function applied during an
engine out go-around is similar to the application of a fixed derate for takeoff,
whereby TAP is able to reduce the minimum control speed restriction.
TAP does not reduce thrust during normal all engine operations, or during engine
out takeoffs where the correct operational thrust (i.e. thrust levers are not
advanced during a derated takeoff) and speeds are maintained. This applies to all
takeoff thrust conditions; full rated thrust, assumed temperature derate, and fixed
thrust derate. TAP may encounter conditions during an engine out go-around
where it reduces thrust even when flown at the correct operational speeds.
TAP is available only when the EEC and the flight controls are operating in the
normal or alternate modes.
February 15, 2010
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