S 862-061
(9)
Put the left and right alpha vanes at the zero position.
S 862-062
(10)
Verify the indicator on the bypass valve is at Position 1 (OPEN).
S 862-063
(11)
Put the landing gear lever in the OFF position.
S 862-064
(12)
Rotate the left AOA vane counterclockwise to the stops.
S 862-065
(13)
Verify the indicator on the bypass valve moves to Position 2 (CLOSED). After the indicator shows that the valve is in the CLOSED position, listen to the valve motor and make sure that the motor is not operating.
S 862-066
(14)
Rotate the left AOA vane clockwise back to its "zero" position.
S 862-067
(15)
Verify the indicator on the bypass valve moves to Position 1 (OPEN). After the indicator shows that the valve is in the OPEN position, listen to the valve motor and make sure that the motor is not operating.
(16)
Position the flaps to the full up position.
(17)
Restore the airplane to the normal condition.
S 862-070
S 442-071
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32-31-81
ALL ú ú 01 Page 207 ú Jul 12/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
737-300/400/500MAINTENANCE MANUAL
MAIN GEAR EXTENSION AND RETRACTION - DESCRIPTION AND OPERATION
______________________________________________________________
1. General_______
A. The main gear extension system raises and lowers the main gear. The main gear retracts or extends simultaneously with the nose gear when the landing gear control handle is moved into the UP or DN detent. A main gear actuator applies the force required to raise and lower the gear. The actuator works in conjunction with a walking beam to apply force to the main gear shock strut and swing the gear inboard. Both the actuator and the walking beam are connected to lugs on the shock strut. The outboard ends of the actuator and the walking beam pivot on a beam hanger attached to the airplane structure (Fig. 1). A main gear lock mechanism locks the gear positively in the up or down positions. The lock mechanism is mounted on a reaction link located between the upper ends of the shock strut and side strut. A lock actuator to engage and disengage the uplock is mounted on the side strut end of the reaction link. The gear is locked down by a folding lock strut located between the center of the reaction link and the side strut center hinge. The lock strut is operated by the downlock actuator, mounted on the shock strut end of the reaction link. Spring bungees between the shock strut and lock strut serve to hold the lock strut in either the locked or unlocked positions.
B. ON SOME AIRPLANES; Isolation valves are provided for the main landing gear to shut off hydraulic pressure to each main gear. This enables work to be done on the landing gear without depressurizing the hydraulic system. The valves are located in the left wheel well.
2. Main Gear Actuator__________________
A. The main gear actuator converts hydraulic pressure into mechanical power for retraction and extension of the main landing gear. The actuator is a hydraulic piston type, with snubbing action to slow movement when limits of travel are approached (Fig. 2). The cylinder head end of the actuator is attached to the beam hanger. The piston rod is attached to a lug on the shock strut. The actuator and the walking beam are located in the wing outboard of the shock strut. Hydraulic fluid is directed to the head end of the actuator through two flexible hoses. Fluid from one hose flows into the cylinder head. A transfer tube built onto the actuator directs fluid from the second hose to the rod end of the cylinder.
B. When the main gear actuator is pressurized to extend, opposing forces from the actuator and walking beam act to rotate the gear. The gear swings inboard and up into the wheel well. When the actuator is pressurized to retract, the forces rotate the gear in the opposite direction to extend the gear.
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本文链接地址：737-300 400 500 AMM 飞机维护手册 起落架 LANDING GEAR 2(64)
