737 MAX Flight Crew Operations Manual
Supplementary Procedures -
Adverse Weather
SP.16.10
MN-FLT-OH-201
ENGINE ANTI-ICE switches.............................. ON
PM
Verify that the COWL VALVE OPEN lights illuminate
bright, then dim.
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 minimum of 30% N1).
When engine anti-ice is no longer needed:
ENGINE ANTI-ICE switches.............................OFF
PM
Verify that the COWL VALVE OPEN lights illuminate
bright, then extinguish.
YA201 - YD256, YF631 - YV671
ENGINE START switches ..................................OFF
PM
Fan Ice Removal
CAUTION: Avoid prolonged operation in moderate to severe icing
conditions.
Prolonged operation in moderate to severe icing conditions can lead to
fan blade/spinner icing and engine vibration. Severe icing can usually be
avoided by a change in altitude and/or airspeed. If flight in moderate to
severe icing conditions cannot be avoided, do the following on both
engines, one engine at a time:
Note:
Engine vibration can reduce to a low level before 80% N1 is
reached, however, thrust increase must continue to a
minimum of 80% N1 to remove ice from the fan blades.
Note:
Engine vibration can indicate full scale before shedding ice,
however, this has no adverse effect on the engine.
ENGINE START switches (both) ........................FLT
PM
Autothrottle (if engaged) .......................... Disengage
PF
Thrust ............................................................Increase
PF
Increase thrust to a minimum of 80% N1 for
approximately 1 second to ensure the fan blades and
spinner are clear of ice.
March 1, 2021