737 MAX Flight Crew Operations Manual
Anti-Ice, Rain -
System Description
MN-FLT-OH-201
3.20.7
Both valves close if either engine thrust is above the takeoff warning setting or
either temperature sensor senses a duct overtemperature. The valves automatically
reopen if thrust on both engines is reduced and both temperature sensors are cool.
If either engine is above the takeoff warning setting and the WING ANTI–ICE
switch is ON, the L VALVE and R VALVE lights are inhibited. The switch
remains in the ON position regardless of control valve position. The WING
ANTI–ICE switch automatically trips OFF at lift–off when the air/ground sensor
goes to the air mode.
Positioning the WING ANTI–ICE switch to ON in flight:
• opens both control valves
• sets stall warning logic for icing conditions.
Note:
Stall warning logic adjusts stick shaker and minimum maneuver speed
bars on airspeed indications. FMC displayed VREF is not adjusted
automatically.
Note:
Stall warning logic remains set for icing conditions for the remainder
of the flight, regardless of subsequent WING ANTI–ICE switch
position.
Duct temperature and thrust setting logic are disabled and have no affect on
control valve operation in flight.
Illumination of the amber L VALVE and/or R VALVE light(s) indicates the related
wing anti-ice control valve position disagrees with the WING ANTI-ICE switch
position.
March 1, 2021
