OPERATIONS MANUAL

Automatic Flight
MCP:
Flight level change switch
Push Engages FLCH SPD pitch mode.
Switch light illuminates and both PFDs
annunciate FLCH SPD.
If FMC has been controlling command speed:
Unblanks IAS/Mach window. If FMC selected
command speed is valid, IAS/Mach window
displays command speed, else current speed.
If FMC has not been controlling command speed:
If the selected command speed is lower than the
current speed, IAS/Mach window displays the
current speed.
If selected altitude is higher than current altitude:
If CRZ has been the reference thrust limit, limit
changes to CLB; or to CON if any engine is out.
When FLCH SPD is engaged:
AFDS commands pitch to maintain the airspeed
displayed in IAS/Mach window; or, if limits are
exceeded, the respective minimum or maximum
airspeed. A/T engages in THR mode which
adjusts the aircraft’s vertical speed so that the
flight level change will take 2 minutes; if the level
change is too great to be achieved in 2 minutes,
throttles move to thrust reference limit for
climb, or to idle for descent. When the planned
vertical speed is stabilized for descent, A/T
engages in HOLD mode to allow manual thrust
adjustments. For climb, HOLD is not available.
When approaching the selected altitude, FLCH
operates in altitude acquire submode; in this
submode, A/T operates in SPD mode while
FLCH guides along a smooth altitude capture
profile. When selected altitude is reached, pitch
mode changes to ALT.
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