737 MAX Flight Crew Operations Manual
Warning Systems -
System Description
MN-FLT-OH-201
15.20.23
1B401, 1B402, 1B801 - 1B824
Alerts are available approximately 12 seconds after the weather radar begins
scanning for windshear. The Predictive Windshear System (PWS) detects the
presence of windshear ahead of the aircraft, giving 10 to 60 seconds of warning
before the encounter. The windshear mode will automatically be turned on under
the following conditions:
• inflight, below 1,800 feet AGL
• on the ground, engine at takeoff thrust setting
If windshear is not detected, weather radar returns show only after pushing the
EFIS control panel WXR switch.
1B401, 1B402, 1B801 - 1B824
Predictive Windshear Inhibits
During takeoff and landing, new predictive windshear caution alerts are inhibited
between 80 knots and 400 feet RA, and new warning alerts between 100 knots and
50 feet RA. These inhibits do not remove existing predictive windshear alerts. If
a warning/caution event occurs before those boundaries, it will remain on the
display and the complete aural callout will be annunciated.
.5 NM
1.5 NM
W
A
R
N
I
N
G
Predictive Windshear Alert Area
25°
On Ground
25°
3 NM
W
A
R
N
I
N
G
Caution
Caution
25°
In Flight
25°
3 NM
Caution
.5 NM
RDR-4000 INTUVUE RADAR
October 26, 2021