787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Flight Management, Navigation -
FMC Descent and Approach
Copyright © The Boeing Company. See title page for details.
11.43.28 D615Z003-TBC
Displays UNABLE FUEL if the fuel prediction for the alternate airport is less than
zero.
Displays UNABLE ALT when:
• the entered altitude for an alternate is above the calculated maximum
altitude for that alternate
• the entered altitude is above the airplane and the airplane would be past the
top of descent for the alternate if it attained the entered altitude
• conditions for UNABLE FUEL and UNABLE ALT both occur
This prompt performs the same function as described on the ALTN 1/2 page.
Note: After a divert is executed, the XXXX ALTN page data is not updated until
all CDU displays change to a page other than the XXXX ALTN page.
Holding
The FMC computes holding patterns with constant radius turns based on current
wind 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.
With LNAV active before sequencing the holding fix, holding pattern entries are
determined by the following:
• airplane track, not heading or direction from which the active route
approaches the holding pattern, determines the entry method used
(parallel, teardrop, or direct entry)
• the airplane flies the initial outbound leg a computed distance from the
holding fix, rather than a specific time. The computed distance is a
function of the command airspeed and computed wind at the time the
holding pattern becomes active
• teardrop entries use a 40 degree offset angle
11
XXXX DIVERT NOW
August 14, 2009
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