787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Landing Gear -
System Description
Copyright © The Boeing Company. See title page for details.
14.20.2 D615Z003-TBC
If any gear is not up and locked up after the normal transit time, the EICAS caution
message GEAR DISAGREE is displayed. The EICAS gear position indication
changes to the expanded non–normal format, with the affected gear displayed as
in–transit or down, if the gear never unlocked from the down position. The EICAS
advisory message GEAR DOOR is displayed if any hydraulically actuated door is
not closed after normal transit time.
Landing Gear Extension
When the landing gear lever is moved to DN, the landing gear doors open, the gear
are unlocked, and the in–transit indication is displayed on the EICAS landing gear
position indication.
The gear free–fall without hydraulic power to the down and locked position. The
downlocks are powered to the locked position, all hydraulically actuated gear
doors close, and the main gear trucks hydraulically tilt to the flight position. When
all gear are down and locked, the EICAS gear position indication displays
DOWN.
The EICAS caution message GEAR DISAGREE is displayed if any gear is not
locked down (side and drag brace on the same main gear not locked, or nose gear
drag brace not locked) after the normal transit time. The EICAS gear position
indication changes to the expanded non–normal format, with the affected gear
displayed as in transit (or UP if the gear never unlocked from the up position).
If only one brace on a main gear is locked (either drag or side brace not locked)
after the normal transit time, the EICAS caution message MAIN GEAR DRAG
BRACE L, R or MAIN GEAR SIDE BRACE L, R is displayed for the affected
gear. The EICAS gear position indication changes to the expanded non–normal
format, with the affected gear displayed as in transit. The EICAS advisory
message GEAR DOOR displays if any hydraulically actuated door is not closed
after the normal transit time.
Landing Gear Alternate Extension
The alternate landing gear extension system uses a dedicated DC powered electric
hydraulic pump and center hydraulic system fluid to extend the landing gear.
Selecting DOWN on the ALTERNATE GEAR switch releases all door and gear
uplocks. The landing gear free–fall to the down and locked position. The landing
gear lever position has no effect on landing gear alternate extension.
The EICAS landing gear position indication displays the expanded gear position
indication when the alternate extension system is used. During alternate
extension, the EICAS message GEAR DOOR is displayed because all the
hydraulically powered gear doors remain open.
February 15, 2010
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