737 Flight Crew Operations Manual
Landing Gear -
System Description
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14.20.4 D6-27370-866-EGP
Antiskid Protection
Antiskid protection is provided in the normal and alternate brake systems.
The normal brake hydraulic system provides each main gear wheel with
individual antiskid protection. When the system detects a skid, the associated
antiskid valve reduces brake pressure until skidding stops. The alternate brake
hydraulic system works similar to the normal system however antiskid protection
is applied to main gear wheel pairs instead of individual wheels.
Both normal and alternate brake systems provide skid, locked wheel, touchdown
and hydroplane protection.
Antiskid protection is available even with loss of both hydraulic systems.
Autobrake System
The autobrake system uses hydraulic system B pressure to provide maximum
deceleration for rejected takeoff and automatic braking at preselected deceleration
rates immediately after touchdown. The system operates only when the normal
brake system is functioning. Antiskid system protection is provided during
autobrake operation.
Rejected Takeoff (RTO)
The RTO mode can be selected only when on the ground. Upon selection, the
AUTO BRAKE DISARM light illuminates for one to two seconds and then
extinguishes, indicating that an automatic self–test has been successfully
accomplished.
To arm the RTO mode prior to takeoff the following conditions must exist:
• airplane on the ground
• antiskid and autobrake systems operational
• AUTO BRAKE select switch positioned to RTO
• wheel speed less than 60 knots
• forward thrust levers positioned to IDLE.
With RTO selected, if the takeoff is rejected prior to wheel speed reaching 90
knots autobraking is not initiated, the AUTO BRAKE DISARM light does not
illuminate and the RTO autobrake function remains armed. If the takeoff is
rejected after reaching a wheel speed of 90 knots, maximum braking is applied
automatically when the forward thrust levers are retarded to IDLE.
September 28, 2006
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