737 MAX Flight Crew Operations Manual
Supplementary Procedures -
Adverse Weather
MN-FLT-OH-201
SP.16.7
CAUTION: When operating the engines over significant amounts
of standing de-icing or anti-icing fluid, limit thrust to
the minimum required. Excessive ingestion of de-icing
or anti-icing fluid can cause the fluid to build up on
the engine compressor blades resulting in compressor
stalls and engine surges.
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:
Check that the area behind the airplane is clear.
C
Run-up to a minimum of 70% N1 for approximately 30
seconds duration at intervals no greater than 30 minutes.
C
Note:
Fan blade ice build-up is cumulative. If the fan spinner and
fan blades were not deiced prior to taxi out, the time the
engines were operating during the taxi in should be included
in the 30 minute interval.
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.
C
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 enhance ice shedding.
De-icing/Anti-icing
Testing of undiluted de-icing/anti-icing fluids has shown that some of the
fluid remains on the wing during takeoff rotation and initial climb. The
residual fluid causes a temporary decrease in lift and increase in drag,
however, the effects are temporary. Use the normal takeoff rotation rate.
CAUTION: Operate the APU during de-icing only if necessary. If
the APU is running, ingestion of de-icing fluid causes
objectionable fumes and odors to enter the airplane.
Ingestion of snow, slush, ice, or de-icing/anti-icing fluid
can also cause damage to the APU.
If de-icing/anti-icing is needed:
APU ...........................................................As needed
F/O
March 1, 2021
