737 MAX Flight Crew Operations Manual
Supplementary Procedures -
Adverse Weather
MN-FLT-OH-201
SP.16.5
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,
• check that the area around the airplane is clear, 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.
Wing Anti-ice Operation - On the Ground
Use wing anti-ice during all ground operations between engine start and
takeoff when icing conditions exist or are anticipated, unless the airplane
is, or will be protected by the application of Type II or Type IV fluid in
compliance with an approved ground de-icing program.
WARNING: Do not use wing anti-ice as an alternative for ground
de-icing/anti-icing. Close inspection is still needed to
ensure that no frost, snow or ice is adhering to the
wing, leading edge devices, stabilizer, control
surfaces or other critical airplane components at
takeoff.
CAUTION: Do not use wing anti-ice when OAT is above 10°C.
When wing anti-ice is needed:
WING ANTI-ICE switch ..................................... ON
F/O
Verify that the L and R VALVE OPEN lights illuminate
bright, then dim.
Note:
The wing anti-ice VALVE OPEN lights may cycle
bright/dim due to the control valves cycling closed/open in
response to thrust setting and duct temperature logic.
When wing anti-ice is no longer needed:
WING ANTI-ICE switch ................................... OFF
F/O
Verify that the L and R VALVE OPEN lights illuminate
bright, then extinguish.
March 1, 2021
