737 MAX Flight Crew Operations Manual
Supplementary Procedures -
Adverse Weather
MN-FLT-OH-201
SP.16.15
Verify that the COWL ANTI-ICE lights are extinguished.
Note:
If the COWL VALVE OPEN lights remain illuminated
bright with engines at IDLE, do the following:
• verify APU BLEED air switch is in the OFF posiiton,
• verify ISOLATION VALVE switch is in the AUTO
position, and
• increase thrust slightly (up to a maximum of 30% N1).
When engine anti-ice is no longer needed:
ENGINE ANTI-ICE switches ............................ OFF
F/O
Verify that the COWL VALVE OPEN lights illuminate
bright, then extinguish.
YA201 - YD256, YF631 - YV671
ENGINE START switches ................................. OFF
F/O
When engine anti-ice is required and the OAT is 3°C or below,
an engine run up is recommended to minimize ice build-up.
Use the following procedure:
C
Check that the area behind the airplane is clear.
Run-up to a minimum of 70% N1 for approximately 30 seconds duration
at intervals no greater than 30 minutes.
If airport surface conditions and the concentration of aircraft do not allow
the engine thrust level to be increased to 70% N1, then set a thrust level
as high as practical and time at that thrust level.
Note:
When operating in conditions of freezing rain, freezing drizzle,
freezing fog or heavy snow, run-ups to a minimum of 70% N1
for approximately 1 second duration at intervals no greater than
10 minutes should be considered.
Shutdown Procedure
Do the following step before starting the normal Shutdown Procedure:
After landing in icing conditions:
WARNING: Ensure that the stabilizer trim wheel handles are
stowed before using electric trim to avoid
personal injury.
Stabilizer trim ............................................Set 5 units
C
Prevents melting snow and ice from running into the
tailcone. Excessive water in the tailcone can freeze and
lock controls.
March 1, 2021
