737 MAX Flight Crew Operations Manual
Supplementary Procedures -
Adverse Weather
SP.16.2
MN-FLT-OH-201
Icing conditions exist when OAT (on the ground) or TAT (in flight) is 10°C
or below and any of the following exist:
• visible moisture (clouds, fog with visibility of one statute mile
(1600m) or less, rain, snow, sleet, ice crystals, and so on) is present,
or
• ice, snow, slush or standing water is present on the ramps, taxiways,
or runways.
CAUTION: Do not use engine or wing anti–ice when OAT (on the
ground) or TAT (in flight) is above 10°C.
Exterior Inspection
Although removal of surface snow, ice and frost is normally a maintenance
function, during preflight procedures, the captain or first officer should
carefully inspect areas where surface snow, ice or frost could change or
affect normal system operations.
Do the normal Exterior Inspection with the following additional steps:
Surfaces ..........................................................................................Check
YA608, YA610, YA631, YB119, YC095, YC453, YD256 - YF832, YK721 - YV671
Takeoff with light coatings of frost, up to 1/8 inch (3 mm) in
thickness, on lower wing surfaces due to cold fuel is allowable;
however, all leading edge devices, all control surfaces, tab surfaces,
upper wing surfaces, winglet surfaces and control surface balance
panel cavities must be free of snow, ice and frost.
Thin hoarfrost is acceptable on the upper surface of the fuselage
provided all vents and ports are clear. Thin hoarfrost is a uniform
white deposit of fine crystalline texture, which usually occurs on
exposed surfaces on a cold and cloudless night, and which is thin
enough to distinguish surface features underneath, such as paint
lines, markings or lettering.
Control surface balance panel cavities ...........................................Check
Check drainage after snow removal. Puddled water may freeze in
flight.
Pitot probes and static ports ...........................................................Check
Verify that all pitot probes and static ports free of snow and ice.
Water rundown after snow removal may freeze immediately
forward of static ports and cause an ice buildup which disturbs
airflow over the static ports resulting in erroneous static readings
even when static ports are clear.
March 1, 2021