Landing Gear -System Description 737 Operations Manual
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:
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airplane on the ground
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antiskid and autobrake systems operational
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AUTO BRAKE select switch positioned to RTO
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wheel speed less than 60 knots
. forward thrust levers positioned to IDLE. The RTO mode is activated when wheel speed reaches 60 knots. If the takeoff is rejected while wheel speed is between 60 and 90 knots, the AUTO BRAKE DISARM light illuminates, autobraking is not initiated. 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. Braking force is the equivalent of full manual braking. The RTO mode is automatically disarmed when the right main gear strut extends.
The AUTO BRAKE DISARM light does not illuminate. The selector switch must be manually positioned to OFF. If a landing is made with RTO selected, no automatic braking action occurs and the AUTO BRAKE DISARM light illuminates two minutes after touchdown. To reset, position the selector to OFF.
Landing
When a landing autobrake selection is made, the system performs a turn–on– self–test. If the turn–on–self–test is not successful, the AUTO BRAKE DISARM light illuminates and the autobrake system does not arm.
Four levels of deceleration can be selected for landing. However, on dry runways, the maximum autobrake deceleration rate in the landing mode is less than that produced by full pedal braking.
After landing, autobrake application begins when:
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both forward thrust levers are retarded to IDLE, and
.
the main wheels spin–up.
Landing Gear -System Description
737 Operations Manual
To maintain the selected landing deceleration rate, autobrake pressure is reduced as other controls, such as thrust reversers and spoilers, contribute to total deceleration. The autobrake system brings the airplane to a complete stop unless the braking is terminated by the pilot.
Autobrake – Disarm
The pilots may disarm the autobrake system by moving the selector switch to the OFF position. This action does not cause the AUTO BRAKE DISARM light to illuminate. After braking has started, any of the following pilot actions disarm the system immediately and illuminate the AUTO BRAKE DISARM light:
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moving the SPEED BRAKE lever to the down detent
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advancing the forward thrust lever(s) after touchdown, or
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applying manual brakes.
Parking Brake
The parking brake can be set with either A or B hydraulic systems pressurized. If A and B hydraulic systems are not pressurized, parking brake pressure is maintained by the brake accumulator. Accumulator pressure is shown on the HYDRAULIC BRAKE PRESSURE indicator.
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本文链接地址：737-300机组操作手册Flight Crew Operations Manual FCOM 3(103)
