737 MAX Flight Crew Operations Manual
Flight Management, Navigation -
Flight Management System
Operation
11.31.26
MN-FLT-OH-201
VNAV Descent and Approach Path
The descent path starts at the calculated top of descent (T/D) point and includes
waypoint altitude restrictions. The path is based on:
After the first “at” or “at or below” restriction, the path angle is constant between
waypoints.
Note:
When passing top of descent and using high target speeds (within
approximately 6 knots of Vmo/Mmo), VNAV may revert to VNAV SPD to
prevent overspeed.
Normally, the target speed is economy speed above the airspeed restriction
altitude and 240 knots below that altitude, until deceleration for approach. VNAV
will not permit descent below the airspeed restriction altitude until the airspeed is
at or below the restricted value plus ten knots. The start and end of the airport
speed restriction deceleration segment is shown on the map as a green open circles
with no labels.
The descent path assumes deceleration to reach the final approach fix (FAF), or
the glideslope intercept point at VREF 40+20 knots.
Target speeds are changed by entries on the DESCENT page. Entries made on the
LEGS page are “at or below” and may limit the target speed. Wind and thrust
assumptions are changed on the DES FORECASTS page.
Deceleration points show on the map as green open circles with the label DECEL.
Deceleration points show prior to:
• airspeed constrained waypoints
• holding patterns
• approach flap extension.
If more than one deceleration segment exists in the flight plan, only the next
deceleration point shows. Deceleration points can also show prior to cruise
holding patterns or other speed reductions.
During descent, VNAV ALT engages if the airplane levels at an MCP altitude not
in the FMC.
VNAV Path Descent
An E/D point must be defined in order to accomplish a path descent. It may be
defined manually or by the selection of an arrival procedure.
• idle thrust
• speedbrakes retracted
• descent wind speed
decreasing with decreasing
altitude
• applicable target speed.
March 1, 2021
