737 MAX Flight Crew Operations Manual
Engines, APU -
Engine System Description
MN-FLT-OH-201
7.20.3
Electronic Engine Control (EEC)
Each engine has a full authority digital EEC. Each EEC has two independent
control channels, with automatic channel transfer if the operating channel fails.
With each engine start or start attempt, the EEC alternates between control
channels. The EEC uses thrust lever inputs to automatically control forward and
reverse thrust. N1 is used by the EEC to set thrust in two control modes: normal
and alternate. Manual selection of the control mode can be made with the EEC
switches on engine panel.
EEC Normal Mode
In the normal mode, the EEC uses sensed flight conditions and bleed air demand
to calculate N1 thrust ratings. The EEC compares commanded N1 to actual N1
and adjusts fuel flow to achieve the commanded N1.
The full rated takeoff thrust for the installed engine is available at a thrust lever
position less than the forward stop. Fixed or assumed temperature derated takeoff
thrust ratings are set at thrust lever positions less than full rated takeoff. The EEC
limits the maximum thrust according to the airplane model as follows:
Note:
Typical engine ratings based on model/series airplane. For actual engine
ratings refer to Performance Dispatch chapter.
1B785, 1B786, 1B807, 1B808, 1J585 - 1J594
• 737-8 – LEAP-1B27 rating
1B401, 1B402, 1B809 - 1B824
• 737-8 – LEAP-1B28 rating
• 737-8 – LEAP-1B28B1 rating
Takeoff Bump Thrust
1B801 - 1B806
Takeoff bump thrust is available when increased thrust is needed for takeoff,
above the normal maximum takeoff thrust setting. When selected using the FMC
N1 LIMIT page, takeoff thrust is increased by either the flight crew or the
autothrottle positioning the thrust levers to set N1 to the reference N1 bug.
Bump thrust is available for takeoff thrust, and is the applied thrust rating for
Go-around thrust. Thrust bump is not applied to max continuous or climb thrust
ratings.
March 1, 2021
