737 Flight Crew Operations Manual
Flight Management, Navigation -
FMC Takeoff and Climb
Boeing Proprietary. Copyright © Boeing. May be subject to export restrictions under EAR. See title page for details.
11.41.2 D6-27370-866-EGP
VNAV Armed for Takeoff
VNAV may be armed on the MCP prior to takeoff provided the following
requirements have been met:
• a valid flight plan has been entered
• performance data has been entered and executed
• both flight director switches have been switched on
• NG aircraft equipped with Collins P4 FCC or later; or Honeywell -710
FCC or later; and CDS BP06 software.
Note: If an older version of FCC or CDS software is installed, VNAV will not
engage nor arm on the ground.
Target Speeds will follow the profile listed in the Climb Phase.
The CDS will annunciate VNAV armed on the FMA when VNAV is selected prior
to takeoff and it is capable of being armed. On takeoff and after reaching 400 feet
above the runway, the FCC will automatically engage VNAV if armed.
To prevent the FCC from engaging on-ground in VNAV SPD mode, if the FCC
engages on-ground, the FMC will clear its VNAV valid discrete, which will force
the FCC to disengage. The FMC will retain the last valid MCP speed that was
above 60 knots that existed prior to the FCC engaging, and will output that as the
FMC speed.
VNAV Takeoff -One Engine Out
During the all engine takeoff flight phase, VNAV will be enabled to automatically
adjust the target airspeed profile upon engine out detection.
If a single engine failure is detected while in the VNAV takeoff flight phase (for
all engines) and below the engine out takeoff acceleration height, the FMC will
calculate and issue a target speed equal to the greater of current airspeed or V2
limited to be less than or equal to V2 + 20 KCAS.
This speed will continue to be updated until an engine failure is detected, at which
point the target speed will be frozen at the present value.
VNAV will continue to generate this target speed until reaching the engine out
acceleration height or when VNAV guidance initiates a level-off prior to reaching
the engine out acceleration height, at which point the VNAV target speed will be
changed to VREF + 70 KCAS (flaps up maneuver speed) subject to the applicable
speed limits for the current airplane configuration.
VNAV will continue to issue the VREF + 70 KCAS target speed through flap
retraction and thrust reduction, and retains this target for obstacle clearance until
the pilot selects and executes the ALL ENG prompt on the CDU or VNAV
transitions to the cruise flight phase to complete the engine-out takeoff flight
phase.
September 27, 2012
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