曝光台 注意防骗
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33. individually [individjuli ] ad. 单独地; 分别地
TEXT
[1] Three separate and independent hydraulic systems are provided to power the
flight controls, landing gear, and thrust reversers. System A and system B are
full-time operating system during flight that share responsibility for all
hydraulically powered components. The standby system is operated only on
demand.
[2] System A hydraulic power operates the following systems:
Landing gear
Nose wheel steering
Left thrust reverser
Ailerons－ower control unit and autopilot actuator
Elevators－power control unit and autopilot actuator .
Elevator feel
Rudder
Inboard flight spoilers 3 and 6.
Ground spoilers.
Alternate brakes.
Power transfer unit.
Fig 13-1 Hydraulic system A
[3] System A pressure is provided by one engine driven pump (EDP) and one
electric motor driven pump (EMDP). A 28V dc motor operated shutoff valve in the
supply line between the reservoir and the engine driven pump is normally
open .This valve is closed and stops the flow of hydraulic fluid to the engine when
the fire handle is pulled .
Fig 13-2 system control and monitoring
[4] Normal system configuration is with both pumps operating to output fluid
pressurized to 3000 psi through the pressure module to the using system. The
pressure module contains pressure filter. low pressure switches, check valves and a
pressure relief valve. Cooling and lubricating fluid from the pumps is filtered and
routed through a heat exchanger in the number one fuel tank before entering the
reservoir. Return fluid from the using systems is filtered at the return module before
entering the reservoir.
[5] Hydraulic system B provides fluid under pressure of 3000 psi to portions of the
flight control, landing gear, and thrust reverser systems. System B hydraulic power
operates the following systems:
Main wheel brakes
Right thrust reverser
Ailerons－power control unit and autopilot actuator.
Elevators－power control unit and autopilot actuator .
Elevator feel
Rudder
Outboard flight spoiler 2 and 7
Trailing edge flaps
Leading edge flaps and slats
Alternate landing gear retraction
Alternate nose wheel steering
Fig 13-3 Hydraulic system B
[6] System B hydraulic pressure is provided by two hydraulic pumps, an EDP
(Engine Driven Pump) and an EMDP (Electric Motor Driven Pump). The pumps
are supplied with fluid from a reservoir pressurized with pneumatic air from the
ECS (Environmental Control System). Output of the pumps is routed to a pressure
module and from there to the using systems. Return fluid from the using system is
routed through a return filter module then to the reservoir. Drain fluid from both
pumps is routed through a heat exchanger before going to the reservoir.
[7] The standby system components are located in the main gear wheel well, on the
keel beam and the aft bulkhead. The standby pump is operated when required to
power the rudder, thrust reversers, or to extend the leading edge devices. The
pump can be turned on by either of three guarded switches on the forward overhead
panel (P5). In addition, the pump automatically switches on and provides standby
pressure to the rudder whenever hydraulic system A or B is lost, the flaps are not up,
the airplane is either in the air or on the ground with wheel speed above 60 knots,
and at least one flight control switch, system A or B, is ON.
[8] When the standby pump is turned on, pressurized fluid is delivered to two motor
- operated shutoff valves on the standby pressure module and to two thrust reverser
shuttle valves. The motor operated shutoff valves which control pressure to the
leading edge devices and to the standby rudder actuator are individually controlled
by switches on the forward overhead panel. The standby rudder shutoff valve is also
opened when the standby hydraulic pump is automatically turned on .
Fig 13-4 Standby system distribution
EXERCISE
A. Find out the explanations of the following words in your “English - Chinese
technical dictionary ”
1. thrust reverser [ P1-155 ]
2. steering tiller [ P1-144 ]
3. aileron [ P1-3 ]
4. power control unit [ P1-116]
5. elevator [ P1-52 ]
6. rudder [ P1-129 ]
7. spoiler [ P1-141 ]
8. power transfer unit [ P1-116 ]
9. reservoir [ P1-125 ]
10. leading edge [ P1-91 ]
11. trailing edge [ P1- 158 ]
12. alternate [ P1-7 ]
13. guarded switch [ P1-72 ]
14. knot [ P1-88 ]
B. Translate the following sentences into Chinese.
1. The hydraulic system A and system B are full - time operating system during
flight that share responsibility for all hydraulically powered components.
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
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航空工程英语基础（中英文对照）(15)
