737 MAX Flight Crew Operations Manual
Flight Management, Navigation -
Flight Management System
Operation
MN-FLT-OH-201
11.31.25
FMCS speed targets constrain the aircraft within its operating limits except when
in the speed intervention mode. These operating limits include stall protection,
maximum operating speed, flap placards, thrust limits, and maneuver margins.
When a navigation data base vertical angle leg is flown (GP x.xx on RTE LEGS
page), VNAV switches to VNAV PTH if not already in VNAV PTH.
In approach phase during speed intervention, the pitch mode remains in VNAV
PTH after speed intervention is exited. The FMC shall remain in the current
vertical mode regardless of IAS MACH selector changes.
Descent
VNAV performs descents using pitch control to maintain a vertical path. Thrust is
used to control speed, similar to a glideslope in three dimensions.
Top Of Descent (T/D)
The point where the cruise phase changes to the descent phase is the top of
descent. The T/D point is shown on the map as a green open circle with the label
T/D. T/D is calculated from an end of descent (E/D) point.
Intermediate T/D points show on the map as green open circles with the label
T/D–XXXXX (altitude). Intermediate T/D points exist when path segments
between altitude restricted waypoints produce a level path segment. The
intermediate T/D point shows where the descent will resume.
When an exit from a holding pattern is requested by the pilot through CDU action:
• a turn path to the inbound leg will be generated immediately if the
airplane is on the outbound leg or in the fix end turn when the T/D does
not occur in the hold pattern.
• the entire hold pattern shall be flown when the T/D does occur in the
hold pattern.
End of Descent (E/D)
The FMC calculates a descent path based on airspeed restrictions, altitude
restrictions and the end of descent (E/D) point. The E/D point is shown on the map
as a green open circle with the label E/D. The E/D is the last of the following
which is not preceded by a lateral discontinuity:
• the runway threshold for approaches with a runway waypoint on the
active RTE LEGS page, or
• the missed approach point for approaches not showing a runway
waypoint on the active RTE LEGS page, or
• the last descent waypoint, or
• the lowest “at” altitude restriction if no arrival procedure is entered.
Entering an instrument arrival procedure provides an E/D point.
March 1, 2021
