737 MAX Flight Crew Operations Manual
Flight Controls -
System Description
9.20.4
MN-FLT-OH-201
Flight Spoilers
Four flight spoilers are located on the upper surface of each wing. Each hydraulic
system, A and B, is dedicated to a different set of spoiler pairs to provide isolation
and maintain symmetric operation in the event of hydraulic system failure.
Hydraulic pressure shutoff valves are controlled by the two flight SPOILER
switches.
Flight spoilers are used as speed brakes to increase drag and reduce lift, both in
flight and on the ground. The flight spoilers also supplement roll control in
response to control wheel commands.
Under normal conditions, roll commands are transmitted from the First Officer’s
control wheel sensors to the SCE unit, which mixes roll commands with
speedbrake commands from sensors on the speedbrake lever and sends the spoiler
extension commands to each of the flight spoilers.
The flight spoilers rise on the wing with up aileron and remain faired on the wing
with down aileron. When the control wheel is displaced more than approximately
10°, spoiler deflection is initiated.
March 1, 2021
