787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Engines, APU -
Engine System Description
Copyright © The Boeing Company. See title page for details.
D615Z003-TBC 7.20.9
[Option – GE engines]
Flight deck indications, when the thrust is actively being reduced by the TAP
function, are indicated on the EICAS engine display for the high thrust engine. As
TAP reduces thrust, the maximum and commanded N1 tics move down to the
reduced TAP thrust value, and the actual N1 indication follows. The
reference/target N1 indication and the thrust levers do not move. As TAP increases
thrust back to normal, the maximum and commanded N1 tics on the high thrust
engine indication moves up until they again match the reference/target N1
indication.
[Option – RR engines]
Flight deck indications, when the thrust is actively being reduced by the TAP
function, is indicated on the EICAS engine display for the high thrust engine. As
TAP reduces thrust, the maximum and commanded TPR tics move down to the
reduced TAP thrust value, and the actual TPR indication follows. The
reference/target TPR indication and the thrust levers do not move. As TAP
increases thrust back to normal, the maximum and commanded TPR tics on the
high thrust engine indication move up until they again match the reference/target
TPR indication.
The EICAS advisory message THRUST ASYM PROT is displayed if the TAP
function is inoperative.
For additional information on TAP, refer to:
• Alerts Displayed on the PFD
, Ch. 15, Sec. 10
• Alerts Displayed on the HUD
, Ch. 15, Sec. 10
• Thrust Asymmetry Minimum Speed (TAMS)
, Ch. 15, Sec. 20
EEC Idle Selection
The EEC selects minimum idle or approach idle automatically. Minimum idle is a
lower thrust than approach idle. Minimum idle is selected for ground operation
and most phases of flight. Approach idle is selected in flight when:
• engine anti–ice is operating, or
• the flaps are commanded to 25 or greater, or
• the landing gear is selected DOWN
Approach idle decreases acceleration time for go–around. Approach idle is
maintained until after touchdown when the EEC selects minimum idle.
Engine Start and Ignition System
The engines can only be started using the autostart system.
February 15, 2010
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