737 MAX Flight Crew Operations Manual
Warning Systems -
System Description
15.20.20
MN-FLT-OH-201
On-Ground Overrun Warning
1B785, 1B786, 1B814 - 1J594
(as installed)
The On-Ground Overrun Warning alerts the alert crew that they must immediately
apply maximum manual braking and maximum reverse thrust consistent with
conditions, to stop the airplane by the end of the runway. The alert is armed from
three seconds after touchdown until the airplane slows below 20 knots ground
speed, or comes within 1000 feet of the runway end.
The alert consists of a MAX REVERSE visual alert shown on the Primary Flight
Display (PFD), and a "MAX BRAKES, MAX REVERSE" aural alert. The MAX
REVERSE visual alert is removed when the airplane slows below 20 knots
groundspeed. The aural alert will only sound once.
The Enhanced Ground Proximity Warning System (EGPWS) continually
computes a maximum effort stopping distance. The on-ground overrun alert
activates when the maximum effort stopping distance exceeds the distance to the
end of the runway. The distance to the end of the runway is based on the EGPWS
runway database and the airplane’s position.
The on-ground overrun alert is inhibited when any of the following conditions are
true:
• Airplane heading differs from the runway heading by more than 20
degrees;
• the air/ground signal indicates the airplane is in the air;
• the ground speed is less than 20 knots;
• the distance remaining to the end of the runway is less than 1000 feet;
• the airplane’s position accuracy is insufficient;
• the Runway Inhibit switch on the GPWS control panel is in the
INHIBIT position;
• left or right thrust lever is above the idle position (the airplane is
conducting an initial takeoff, or a go-around will be initiated);
• the flap setting is not 15, 30 or 40 degrees (the flaps are not set in a
landing configuration);
• the radio altitude is 10 feet or greater.
SPEEDBRAKE Warning
1B814 - 1B824
(as installed)
The speedbrake alert provides a time-critical warning when speedbrakes are not
deployed during a landing or rejected takeoff above 80 knots.
The alert consists of a SPEEDBRAKE visual alert shown on the Primary Flight
Display (PFD), and a "SPEEDBRAKE, SPEEDBRAKE" aural alert. The aural
alert does not repeat.
October 26, 2021