737 MAX Flight Crew Operations Manual
Supplementary Procedures -
Air Systems
MN-FLT-OH-201
SP.2.3
Outflow valve switch................................................................... CLOSE
Verify outflow valve position indicator moves toward CLOSE.
Outflow valve switch..................................................................... OPEN
Verify outflow valve position indicator moves toward OPEN.
Pressurization mode selector .........................................................AUTO
Verify outflow valve position indicator moves toward OPEN.
MANUAL light – extinguished.
Manual Mode Operation
CAUTION: Switch actuation to the manual mode causes an
immediate response by the outflow valve. Full range
of motion of the outflow valve can take up to 20
seconds.
Pressurization mode selector .......................................................... MAN
MANUAL light – illuminated
CABIN/FLIGHT ALTITUDE placard........................................... Check
Determine the desired cabin altitude.
If a higher cabin altitude is desired:
Outflow valve switch (momentarily) ..................................OPEN
Verify the outflow valve position indicator moves right, cabin
altitude climbs at the desired rate, and differential pressure
decreases. Repeat as necessary.
If a lower cabin altitude is desired:
Outflow valve switch (momentarily) ................................CLOSE
Verify the outflow valve position indicator moves left, cabin
altitude descends at the desired rate, and differential pressure
increases. Repeat as necessary.
During Descent
Thrust lever changes should be made as slowly as possible to prevent
excessive pressure bumps.
March 1, 2021
