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If the current flight level is above the maximum start altitude, the maximum start
altitude and respective airspeed range are displayed.
Secondary engine indications are displayed automatically when a FUEL
CONTROL switch is moved to CUTOFF in flight or if N2 RPM goes below idle
RPM while in flight. A start assist indication is displayed above to the N3
indication if airspeed is below that recommended for a windmilling start.
Refer to Engine In–Flight Start, Chapter NNC.7 for the in–flight start procedure.
For in–flight starts, autostart makes continuous start attempts until the engine
either starts or the pilot aborts the start attempt by positioning the FUEL
CONTROL switch to CUTOFF (and positioning the START switch to NORM if
it was a starter assisted attempt)
During a windmilling in–flight start, the EEC monitors engine parameters to
provide the best fuel schedule to ensure the shortest possible start time.
Engine Ignition
Each engine has two ignitors. The EEC automatically selects the appropriate
ignitor(s). The EEC alternates ignitors for successive engine ground starts. Dual
ignitors are always used for in–flight starts.
DC power is the normal power source for ignition.
Auto–Relight
(TBD).
787 Flight Crew Operations Manual
Engines, APU -
Engine System Description
7.20.8 Boeing Proprietary
Engine Start and Ignition System Schematic
VALVE
FUEL
ENGINE
IGNITOR IGNITOR
SPAR
VALVE
FUEL
STARTER/
EEC
FUEL
FUEL CONTROL
RUN
CUTOFF
L R
START START
NORM NORM
START
ELECTRICAL
POWER
GENERATORS
787 Flight Crew Operations Manual
Engines, APU -
Engine System Description
Boeing Proprietary 7.20.9
Engine Fuel System
Fuel is supplied by fuel pumps located in the fuel tanks. The fuel flows through a
spar fuel valve located in the main tank. It then passes through the first stage
engine fuel pump where additional pressure is added. It flows through a fuel/oil
heat exchanger where it is preheated. A fuel filter removes contaminants. The
second stage of the engine fuel pump adds more pressure before the fuel reaches
the fuel metering unit. The fuel metering unit adjusts fuel flow to meet thrust
requirements. The fuel then flows through the engine fuel valve into the engine.
The spar and engine fuel valves allow fuel flow to the engine when both valves
are open. The spar fuel valve opens when the engine fire switch is IN and either
the START selector is in START or the FUEL CONTROL switch is in RUN. The
engine fuel valve opens when the engine fire switch is IN and the FUEL
CONTROL switch is in RUN. Both valves close when the engine fire switch is
OUT or the FUEL CONTROL switch is in CUTOFF and the START selector is
in NORM.
Fuel flow is measured after passing through the engine fuel valve. Fuel flow is
displayed on the secondary engine display. Fuel flow information is also provided
to the FMS.
787 Flight Crew Operations Manual
Engines, APU -
Engine System Description
7.20.10 Boeing Proprietary
Engine Fuel System Schematic
FUEL
ENGINE FIRE EEC
SWITCH
DISCH
1 2RIGHT
FUEL CONTROL
RUN
CUTOFF
L R
B
FUEL
METERING
UNIT
STAGE
SECOND
EXCHANGER
FUEL/OIL HEAT
FUEL
FILTER
FIRST
STAGE
OIL
SPAR FUEL
VALVE
787 Flight Crew Operations Manual
Engines, APU -
Engine System Description
Boeing Proprietary 7.20.11
Engine Oil System
The oil system provides pressurized oil to lubricate and cool the engine main
bearings, gears and accessory drives. The oil system also provides automatic fuel
heating for fuel system icing protection.
There is no minimum oil quantity limit (no amber or red line limit); however, a
low oil quantity causes automatic display of the secondary engine display and
reverses the display indication to show black numbers on a white background.
There are no operating limitations for the engine oil quantity; therefore, there are
no flight crew procedures based solely on a response to low oil quantity.
Engine Oil System
Schematic
Thrust Reverser System
Each engine has an hydraulically actuated fan air thrust reverser. Reverse thrust is
available only on the ground.
The reverse thrust levers can be raised only when the forward thrust levers are in
the idle position. When the reverse thrust levers are raised, the EEC opens the
reverser isolation valve. The EEC inhibits reverser isolation valve actuation and
reverser deployment unless the airplane is on the ground with the engine running.
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787机组操作手册Flight Crew Operations Manual 2(55)
