737 MAX Flight Crew Operations Manual
Warning Systems -
System Description
15.20.26
MN-FLT-OH-201
Enhanced Bank Angle Warning
The Enhanced Bank Angle Warning provides a time-critical warning in case of a
roll upset greater than 45 degrees of bank. The alert consists of a curved red arrow
on the PFD as well as a GPWS derived aural alert. The roll command arrow and
voice aural alerts indicate the shortest direction to return the airplane to wings
level. If the airplane is banked beyond 45 degrees to the right or left, the arrow
appears pointing to the left or right, and the aural repeats "ROLL
LEFT(RIGHT)...ROLL LEFT(RIGHT)." The voice aural repeats at intervals of 5
seconds. The alert stops when the bank angle decreases below 35 degrees for at
least 2 seconds, or immediately when the bank angle decreases to less than 10
degrees.
There are a number of inputs and inhibited conditions for the Enhanced Bank
Angle Warning:
• At pitch angles less than 25 degrees nose up, the ROLL LEFT (RIGHT)
warning triggers at 45 degrees of bank, replacing the standard 45 degree
BANK ANGLE alert.
• When pitch attitude exceeds 25 degrees nose up, the ROLL
LEFT(RIGHT) warning alert is suppressed until 65 degrees of bank.
This feature is called the Pitch Attitude Latch.
• The Pitch Attitude Latch is deactivated when the pitch attitude exceeds
25 degrees nose up and bank angle is less than 60 degrees, or the pitch
attitude decreases below 10 degrees nose up.
• When the warning is displayed, the flight director is removed from the
display.
• When the warning is displayed, TCAS resolution advisories will not
appear on the display.
• If stick shaker is activated, the Enhanced Bank Angle Warning is
suppressed.
• If the roll attitude comparator detects a difference between IRS inputs,
the Enhanced Bank Angle Warning is inhibited.
The roll command arrow points in the shortest direction to wings level. If the bank
angle passes 180 degrees, the roll command arrow points in the new shortest
direction to wings level.
The roll command arrow is removed when the bank angle is less than 35 degrees
for two seconds, allowing the flight crew to return to a 30 degree bank, if desired.
If the crew continues to roll quickly towards wings level, the roll command arrow
is removed immediately at 10 degrees of bank, in order to prevent overbanking in
the other direction.
October 26, 2021
