787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Automatic Flight -
Controls and Indicators
Copyright © The Boeing Company. See title page for details.
D615Z003-TBC 4.10.7
LNAV is disengaged:
• by selecting heading hold (HDG HOLD) or track hold (TRK HOLD)
• by selecting heading select (HDG SEL) or track select (TRK SEL)
• when LOC or FAC engages
• if there is a dual or triple FMC failure (LNAV may be re–engaged if one
FMC remains functional)
LNAV is disarmed by pushing the LNAV switch a second time, or by arming
LOC/FAC or APP.
Illuminated (white) – the LNAV mode is armed or engaged.
Push –
• arms, engages, or disarms VNAV as the pitch mode
• displays VNAV as armed mode on PFD (in white) and HUD pitch flight
mode annunciator below 400 feet
• VNAV engages at 400 feet AGL
• if VNAV is selected and the FMC has insufficient data to provide VNAV
guidance (such as the gross weight is invalid or there is no end–of–descent
point in descent) displays PERF/VNAV UNAVAILABLE in the CDU help
window
• VNAV SPD, VNAV PTH or VNAV ALT pitch mode is displayed in green
(engaged) on the PFD and HUD pitch flight mode annunciator
• in the VNAV SPD pitch mode, the AFDS commands pitch to hold target
airspeed. The autothrottle operates in the THR REF, THR, IDLE or HOLD
mode, as required by the phase of flight
• in the VNAV PTH pitch mode, the AFDS commands pitch to maintain
FMC target altitude or the VNAV path. The autothrottle maintains speed
• in the VNAV ALT pitch mode, the AFDS commands pitch to maintain the
MCP selected altitude when that altitude is lower than the VNAV
commanded altitude in climb or higher than the VNAV commanded
altitude in descent
• if VNAV is selected and VNAV commands a descent with the MCP
altitude window above the current airplane altitude, the autopilot maintains
the altitude at which VNAV was selected. When on an instrument
approach using VNAV, selecting the missed approach altitude does not
interfere with the VNAV descent
• if VNAV is selected and VNAV commands a climb with the MCP altitude
window below the current airplane altitude, the autopilot maintains the
altitude at which VNAV is selected
• with the VNAV ALT pitch mode engaged, the autothrottle operates in the
speed (SPD) mode
2
LNAV Light
3
Vertical Navigation (VNAV) Switch
June 16, 2008
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