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Two rear spar angle gearboxes
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Angle gearboxes on the output of the inboard transmissions for the inboard flap (transmissions 4 and 5).
Location
The side-of-body angle gearboxes are on the inboard flap support assemblies in the main landing gear wheel wells. Access is through the wheel wells.
The rear spar angle gearboxes are on the rear spar of each wing, near the main landing gear beam. Access is through removable panels under the wings.
The other two angle gearboxes are on the output side of the inboard flap inboard transmissions (4 and 5).
Physical Description
The angle gearboxes are filled with grease and sealed.
The side-of-body angle gearbox weighs 10 lb (4.5 kg). The rear spar angle gearbox weighs 11 lb (5 kg). The angle gearboxes on transmissions 4 and 5 each weigh about 12.5 lb (5.7 kg).
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TRAILING EDGE FLAPS -ANGLE GEARBOXES
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TRAILING EDGE FLAPS -NO-BACK BRAKE
Purpose
The no-back brake helps prevent flap retraction if there is a PDU or torque tube failure.
Location
There is one no-back brake attached to the rear spar of each wing. The no-back brakes are between the two transmissions for the outboard flap on each wing.
Physical Description
The no-back brakes are spring-loaded, skewed-roller, ratchet brakes. They supply a resistive torque during retraction only.
The no-back brakes are filled with oil and sealed. They each weigh 20 lb (9 kg).
Training Information Point
When you operate the flap drive system, observe this caution:
CAUTION: DO NOT OPERATE THE FLAPS CONTINUOUSLY FOR MORE THAN 12 MINUTES IN PRIMARY MODE WITHOUT A 30 MINUTE COOLING OFF PERIOD FOR THE NO-BACK BRAKES. THE NO-BACK BRAKES CAN BECOME TOO HOT.
The no-back brake contains oil and it is necessary to do servicing. Use the oil fill plug.
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TRAILING EDGE FLAPS -NO-BACK BRAKE
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TRAILING EDGE FLAPS -INBOARD FLAP INBOARD TRANSMISSION ASSEMBLY
Purpose
There are two transmission assemblies for each flap surface, an inboard transmission assembly and an outboard transmission assembly.
The inboard flap inboard transmission assembly receives power from the torque tubes to move the inboard flap. This assembly has these components:
*
A transmission
*
A ballscrew
*
A gimbal.
The transmission assembly weighs approximately 95 lb (43 kg).
Location
There is one inboard flap inboard transmission assembly in each main landing gear wheel well.
Transmission
The transmission connects to the torque tubes. Gears in the transmission transmit the power from the torque tubes to the U-joint. The U-joint then turns the ballscrew.
The transmission has a torque brake and a no-back brake. The torque brake prevents excessive loads on the ballscrew if the flap does not move freely. The torque brake is a ball ramp type brake with a torque trip indicator. The trip indicator must be manually reset if it activates.
The no-back brake is a skewed roller type brake. It engages by compression load in the ballscrew caused by airloads on the flap. It prevents flap movement if the PDU or torque tubes fail.
Ballscrew
The transmission turns the ballscrew through a U-joint. The ballscrew has a ballscrew nut which connects to the gimbal. As the ballscrew turns, the ballscrew nut moves the gimbal.
The ballscrew has stops at both ends. The ballscrew nut does not touch the stops during normal operation of the flaps.
Gimbal
The gimbal moves the flap surface. The gimbal connects to the ballscrew nut, and moves as the ballscrew turns.
Training Information Point
If you disconnect the ballscrew from the transmission at the U-joint, make sure that the ballscrew nut stays on the ballscrew.
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TRAILING EDGE FLAPS -INBOARD FLAP INBOARD TRANSMISSION ASSEMBLY
The transmission contains oil and it is necessary to do servicing. Use the oil fill plug. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：777 AMM 飞机维护手册 飞行操纵 Flight Controls 2(37)
