737 MAX Flight Crew Operations Manual
Automatic Flight -
System Description
MN-FLT-OH-201
4.20.33
Minimum Speed Reversion
The AFDS and A/T do not control to a speed which is less than minimum speed
for the current flap configuration. This speed is approximately 1.3 Vs. Minimum
speed, FMC speed, or selected speed, whichever is higher, becomes the AFS
commanded speed. If actual speed becomes equal to or slightly less than the
minimum speed, the underspeed limiting symbol appears in the MCP IAS/MACH
display, and if operating in the V/S mode or CWS P, the AFDS reverts to LVL
CHG. The AFDS will also revert to LVL CHG from VNAV PTH, except when
flying a level segment.
The AFS commands a speed 5 knots greater than minimum speed. Reaching a
speed 5 knots greater than minimum speed reactivates normal MCP speed
selection control. The AFDS commands nose down pitch to increase airspeed if
the thrust levers are not advanced. When actual speed becomes 5 knots greater
than minimum speed, the underspeed limiting symbol disappears.
The A/P disengages and the F/D command bars retract when in a LVL CHG climb
with a command speed equal to minimum speed and a minimum rate of climb
cannot be maintained without decelerating.
There is no minimum speed reversion from the following modes:
• ALT HOLD
• VNAV ALT (as installed)
• VNAV PTH (in a level segment)
• VNAV PTH (not in a level segment and flaps 15 or greater)
• V/S (flaps 15 or greater)
• G/P (as installed)
• G/S.
March 1, 2021
