737 MAX Flight Crew Operations Manual
Flight Management, Navigation -
Controls and Indicators
MN-FLT-OH-201
11.10.25
1
MODE SELECTOR
• MAP – displays full coverage ground map.
• AUTO – automatic weather presentation mode provides display of
windshear out to 5 nm, turbulence out to 60 nm and weather out to 320
nm. Secondary weather returns are shown with black stripes through
them. Hazard Displays for lightning, hail, and Rain Echo Attenuation
Compensation Technique (REACT) indications will be shown also.
• MAN – manual constant altitude (Weather Analysis) mode. The altitude
slice defaults to current altitude upon MAN selection.
Note:
In both AUTO and MAN mode of operation, the weather radar
automatically increases the gain as the aircraft passes into the freezing
layer to help compensate for the decrease in radar reflectivity in this area.
2
MANUAL ALTITUDE CONTROL
• ALT – controls weather analysis altitude from 0 to 60,000 ft. MSL in
increments of 1000 ft. Selected altitude is shown on the Electronic
Flight Display. Active when MAN mode selected.
3
GAIN CONTROL
• CAL – rotate to the CAL position for automatic gain control. The CAL
position results in a calibrated map or weather radar display. Gain
control does not affect turbulence or windshear.
• Manual – rotating the knob out of CAL varies gain between MIN and
MAX. VAR is shown on the display, indicating that the gain has been
changed from the calibrated position.
• MIN – position reduces gain approximately 16 dBz below the CAL
setting.. Rotating the selector toward min reduces precipitation intensity
thresholds, requiring greater intensity precipitation levels to display in
red.
• MAX – position increases gain 10 dBz over the CAL setting. Rotating
the selector toward max increases precipitation intensity thresholds
allowing lesser intensity precipitation levels to display in red. max gain
should only be used at cruise altitudes to help see less reflective frozen
storm tops.
Note:
The GAIN knob can also be used to temporarily suppress the display of
Hazard Icons and Turbulence Indications by moving the GAIN knob out
of the CAL position.
March 1, 2021
