787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Automatic Flight -
System Description
Copyright © The Boeing Company. See title page for details.
4.20.8 D615Z003-TBC
After takeoff, the AFDS commands a pitch attitude to maintain:
• a target speed of V2 plus 15 knots
• if current airspeed remains above the target speed for 5 seconds, the target
airspeed is reset to current airspeed, to a maximum of V2 plus 25 knots
• the IAS/MACH window speed if the IAS/MACH window speed is
changed to a speed greater than the target speed
Note: The AFDS uses the speed set in the IAS/MACH window prior to takeoff
for V2.
In flight, TO/GA is armed when flaps are out of up or glideslope is captured.
When a go–around is initiated, the commanded speed is the MCP IAS/MACH
window or current airspeed, whichever is higher, to a maximum of the
IAS/MACH window speed plus 25 knots. GA displays as the thrust limit on the
primary EICAS engine display.
VNAV –
VNAV is armed by pushing the VNAV switch:
• the switch bar is displayed
• VNAV is annunciated on the PFD pitch mode annunciator in small white
characters below the current pitch mode
• VNAV is annunciated on the HUD pitch mode annunciator in small green
characters below the current pitch mode
VNAV engages above 400 feet after takeoff, if armed. VNAV engages in the
appropriate VNAV mode as required to maintain the current flight path:
• VNAV SPD (engaged) – The AFDS maintains the FMC speed displayed
on the PFD and HUD airspeed indicator and/or the CDU CLIMB or
DESCENT pages. If speed intervention is selected, the MCP IAS/MACH
selector is used to manually select the speed
• VNAV PTH (engaged) – The AFDS maintains FMC altitude or descent
path with pitch commands. If the MCP altitude window is set to the current
cruise altitude as the airplane approaches the top of descent, "FMC
MESSAGE" EICAS message is displayed and the CDU Help window
pops up with instructions to set a lower altitude before top of descent
• VNAV ALT (engaged) – When a conflict occurs between the VNAV
profile and the MCP altitude, the airplane levels and the pitch flight mode
annunciation becomes VNAV ALT. VNAV ALT maintains altitude. To
continue the climb or descent, change the MCP altitude and push the
altitude selector or change the pitch mode
• if an early descent is desired, FLCH, V/S, or FPA may be selected to
descend below the VNAV descent path. If, during the decent, VNAV is
armed and the airplane descent path subsequently intercepts the VNAV
descent path, VNAV engages in VNAV PTH
February 15, 2010
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