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 B.  System No. 1 supplies hydraulic power for the usual operation of the nose landing gear and the body landing gear. It also supplies hydraulic power for the usual operation of the doors for the nose landing gear and the body landing gear. An engine-driven hydraulic pump and/or an air-driven hydraulic pump supplies the hydraulic power. Engine bleed air from the pneumatic system supplies power to the air-driven pump. If the engine-driven pump or the air-driven pump does not operate, the other pump will supply hydraulic pressure to the system.
 C.  System No. 4 supplies hydraulic power for the usual operation of the wing landing gear and the doors. An engine-driven hydraulic pump and/or an air-driven hydraulic pump supplies the hydraulic power. If the engine-driven pump and the air-driven pump do not operate, a motor-driven pump with an alternating current supplies pressure to the system.
 D.  The alternate extension system for the landing gear operates electrically. The alternate extension system unlocks the doors and the landing gear. Gravity extends the landing gear and the doors.
Landing Gear Control Components
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 A.  The control handle for the landing gear is on the right side of the pilots' center instrument panel. A cable system transmits the movement of the control handle to the selector valves. The selector valves are in the wheel wells of the body landing gear. When you move the control handle, the selector valves permit hydraulic pressure to the actuators. This permits the landing gear and the doors to extend and retract. For more data, refer to 32-31-00/001.
Wing Landing Gear
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 A.  The extension and retraction of the wing landing gear operates hydraulically. Hydraulic actuators operate with the walking beams to lift and lower the landing gear. Hydraulic actuators also open and close the wheel well doors. The actuators have internal mechanical locks that lock the doors closed during flight. Smaller actuators operate the landing gear uplocks and the landing gear downlocks. Spring bungees help extend the landing gear to the down and locked position. For more data, refer to 32-32-00/001.
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
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MAINTENANCE MANUAL

 4.  Body Landing Gear
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 A.  The extension and retraction of the body landing gear operates hydraulically. Hydraulic actuators lift and lower the landing gear. Hydraulic actuators also open and close the wheel well doors. The actuators have internal mechanical locks that lock the doors closed during flight. Smaller actuators operate the landing gear uplocks and the landing gear downlocks. Spring bungees help extend the landing gear to the down and locked position. For more data, refer to 32-33-00/001.
 5.  Nose Landing Gear
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 A.  The selector valve that operates the body landing gear also operates the nose landing gear. Thus, the nose landing gear operates at the same time as the wing landing gear and the body landing gear. A hydraulic actuator operates the doors for the nose landing gear. It contains an internal mechanical lock to hold the doors closed during flight. A small actuator locks and unlocks the nose landing gear. For more data, refer to 32-34-00/001.
 6.  Wing Landing Gear Alternate Extension System
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 A.  The alternate extension system for the wing landing gear contains an electrical actuator for each landing gear. The acutator operates a cam and a cable system to unlock the landing gear doors and the landing gear uplock. To start the alternate extension, you must push the applicable button. The buttons are on the right side of the center instrument panel for the pilot. The pilot or the first officer can start the alternate extension of the landing gear. For more data, refer to 32-35-00/001.
 7.  Nose Landing Gear and Body Landing Gear Alternate Extension System
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 A.  The alternate extension system for the nose landing gear and the body landing gear contains electrical actuators and a drive unit. It also contains the applicable linkages and cables to release the landing gear and the doors. To start the alternate extension, you must push the applicable button. The buttons are on the right side of the center instrument panel for the pilot. The pilot or the first officer can start the alternate extension of the landing gear. For more data, refer to 32-36-00/001.
　
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