787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Landing Gear Chapter 14
System Description Section 20
Copyright © The Boeing Company. See title page for details.
D615Z003-TBC 14.20.1
14.20 Landing Gear-System Description
Landing Gear20 System DescriptionSystem Description
Introduction
The airplane has two main landing gear and a single nose gear. The nose gear is a
conventional two–wheel steerable unit. Each main gear has four wheels in tandem
pairs.
Hydraulic power for retraction, extension, and steering is supplied by the center
hydraulic system. An alternate extension system is also provided.
The Electro-Mechanical Brake System has four Electric Brake Actuator
Controllers (EBACs) and thirty-two Electric Brake Actuators (EBAs), four per
wheel brake. Autobrake and antiskid protection are provided. A brake temperature
monitor system displays the temperature for each brake on the GEAR synoptic.
A tire pressure monitor system displays pressure for each tire on the GEAR
synoptic.
Air/Ground Sensing System
In–flight and ground operation of various airplane systems are controlled by the
air/ground sensing system.
The system receives air/ground logic signals from sensors located on each main
landing gear beam. These signals are used to configure the airplane systems to the
appropriate air or ground status.
Landing Gear Operation
The landing gear are normally controlled by the landing gear lever. On the ground,
the lever is held in the DN position by an automatic lever lock. The lever lock can
be manually overridden by pushing and holding the landing gear lever LOCK
OVERRIDE switch. In flight, the lever lock is automatically released through
air/ground sensing.
Landing Gear Retraction
A new landing gear retraction feature on the 787 is the addition of early gear door opening to meet requirements for engine-out, obstaclelimited climb performance. One second after lift-off the main gear doors are automatically commanded open and the main gear trucksare commanded to the stow position.
When the landing gear lever is placed in the UP position the gear retraction
sequence is started. The EICAS landing gear position indication display changes
from a green DOWN indication to a white crosshatch in-transit indication as the
landing gear retract into the wheel wells. After retraction, the landing gear are held
up by uplocks. The EICAS landing gear position indication changes to UP for 10
seconds and then blanks. With the landing gear retracted and all doors closed, the
landing gear hydraulic system is automatically depressurized.
February 15, 2010
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