737 Flight Crew Operations Manual
Flight Management, Navigation -
FMC Descent and Approach
Boeing Proprietary. Copyright © Boeing. May be subject to export restrictions under EAR. See title page for details.
D6-27370-866-EGP 11.43.29
12 Destination–Alternate
Displays computed distance from destination to alternate when missed approach
is selected. Distance includes missed approach procedure plus great circle
distance from last waypoint in missed approach to alternate.
Manual entry is displayed in large font.
Holding
The FMC computes holding patterns with constant radius turns based on current
winds and FMC commanded airspeed. The pattern size is limited to FAA or ICAO
protected airspace. In LNAV, the AFDS tracks the holding pattern using up to a 30
degree bank angle. Strong winds or airspeed in excess of FAA or ICAO entry
speeds may result in the airplane flying outside the protected airspace.
YW273, YW274
(SB Changes YK981 - YQ456)
The FMC generates steering commands to enter, track, and exit a holding pattern
inserted into the active flight plan through CDU action by the pilot.
With LNAV active before sequencing the holding fix, holding pattern entries are
determined by the following:
• the angle between the flight plan leg into the holding fix and the holding
inbound course determines the entry method used (parallel, teardrop or
direct entry)
• the airplane flies the initial outbound leg for a specified time (1.0 minute
at or below 14,000 feet and 1.5 minutes above 14,000 feet)
• teardrop entries use an FMC calculated offset angle designed to
intercept the outbound leg at the point where the inbound turn begins
• parallel and teardrop entries may cause the airplane to fly beyond the
displayed holding pattern; however, the airplane remains in protected
FAA or ICAO limits.
Descent in Holding
YW273, YW274
(SB Changes YK981 - YQ456)
The FMC provides the capability for starting descents when in the holding pattern
airspace with a T/D displayed on one of the holding legs. This is based on the
airplane entering the Hold in the Cruise phase of flight.
• The requirement is to descend in VNAV while holding when a T/D is
encountered in the holding pattern, the MCP ALT has been lowered, and
the EXIT ARMED mode has been executed.
September 15, 2016
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