GROUND SAFTY SENSOR
VOICE
RECORDER
HYDRAULIC
STATICINTERCONNECT
INVERTER
GROUND GND
SAFTY AIR
SENSOR SAFTY SENSOR
SAFTY SENSOR
NOTE:
SWITCH CONTACTS ARE CLOSED WHEN CONDITION IS AS INDICATED BY SWITCH TITLE.
SWITCHES ARE REPRESENTATIVE ONLY AND MAY BE EITHER CONVENTIONAL SWITCHES OR SOLID STATE SWITCHES.
AIR
ANTISKID TEST STALL WARNING ANTI-ICE AIR CONDITIONING TURBOFANS
FLIGHT RECORDER
ANTISKID PRESSURIZATION CONTROL
ELECTRICAL SYSTEM
SAFTY SENSOR
AIR
Air-Ground Sensing Functional Schematic
Figure 4 (Sheet 1)
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
737-300/400/500MAINTENANCE MANUAL
GND
AIR SAFETY SENSOR
Air-Ground Sensing Functional Schematic
Figure 4 (Sheet 2)
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A 737-300/400/500MAINTENANCE MANUAL
3. Landing Gear Extension and Retraction
_____________________________________
A. Extension and retraction of the main and nose gear is by hydraulic power with a manual extension system for lowering the gear when hydraulic power is not available. The landing gear is controlled by a single control lever mounted on the pilots' center panel. Cables from a drum actuated by the control lever transfer motion to a selector valve that directs hydraulic pressure for gear actuation. A safety lock prevents the control lever from entering the UP position when conditions are not right for gear retraction.
B. When the control lever is moved to the UP position, the gear retracts. When the main gears are fully retracted, a seal closes up against the main gear tire circumference. A special hubcap on the outboard wheel fairs the retracted wheel. The shock strut aperture in wing is closed by a shock strut door. A movable section of the shock strut doors carries a section of the seal to close off the upper portion of the tire below the shock strut. Mechanical linkage operates the shock strut door flap as the gear retracts and extends. Doors operated by a linkage connected to the nose gear close off the nose wheel well when the gear retracts. Moving the control lever to the DN position extends all gears. On extension, the nose gear doors open and remain open when the gear is down. With the control lever in OFF position, hydraulic pressure is released from all landing gear hydraulic lines and actuators. The gears are then held in the extended or retracted position by the mechanical locks. A tee handle actuates a crank and cable system for manual extension, which unlocks the gears and allows them to fall to the extended position by gravity. The nose gear doors are opened by mechanical linkage as the gear extends. When operated by the manual extension system, the gears free fall to the down and locked position.
C. When the landing gear is to be retracted with the airplane on the ground, the airplane must be jacked and electrical and hydraulic power must be available.
4. Landing Gear Position Indicating and Warning System
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A. In the landing gear position indicating and warning system, a warning horn and indicator and warning lights provide indication for landing gear down and locked, landing gear not locked, and landing gear position not in accordance with control lever position.
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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 1(6)
