If the RAT ground retraction module stays in retract mode after the STOW switch is released, the high-pressure supply continues. The pressure switch causes the warning light on the RAT control panel to stay on.
R **ON A/C 062-099, 106-149, 151-199, 204-299, 301-399, 401-499,
F. Retraction
It is only possible to retract the RAT when the aircraft is on the ground. Retraction is operated from the RAT control panel which is in the ground service panel of the Blue system. The system must be in the subsequent condition to retract the RAT:
-
the ground test equipment is not attached
-
the cover plate is installed correctly
-
the position arrows on the hub and the lower leg gearbox align (the turbine is then in the index position)
-
the 28V DC switch on the RAT control panel is in the ON position (28 V DC is supplied to the RAT stow panel)
-
the INTERLOCK WARNING lamp on the RAT control panel is off
-
the Blue main-hydraulic system is pressurized.
NOTE : You must manually turn the turbine to the index position.
____
The RAT is retracted hydraulically with the hydraulic supply from the Blue electric pump or from a ground supply.
When the 28V DC switch is set to the ON position, electrical power is supplied to the STOW/RESET selector switch. To retract the RAT you must set the spring-loaded STOW/RESET selector switch to the STOW position and hold it there for approximately 20 seconds, then:
-
the solenoid operates and connects the high pressure supply of the aircraft to the retract side of the RAT ejection jack
-
the high pressure fluid operates the pressure switch and the ACTUATOR PRESSURE indicator lamp comes on to indicate that the RAT ejection jack is pressurized
-
the high pressure supply releases the ejection-jack extend lock and retracts the RAT into the stow compartment
R 1EFF : ALL 1 29-22-00Page 48 1 1 Config-1 Aug 01/05 1 1 1CES 1
-
the return fluid from the ejection jack goes directly into the
low-pressure system of the aircraft. When the RAT is in its fully retracted position:
-
the retract lock of RAT the ejection jack engages and holds the RAT in place,
-
the stowed proximity sensor on the RAT ejection jack operates,
-
the STOWED indicator lamp comes on.
When the STOW/RESET switch is released and is in the neutral position:
-
the RAT ejection jack is depressurized,
-
the ACTUATOR PRESSURE indicator lamp goes off.
When the ON/OFF switch is set to the OFF position:
-
the power supply is stopped,
-
the STOWED indicator lamp goes off.
When the STOW/RESET switch is released before the RAT is fully retracted, the RAT will immediately stop and return in the fully extended position. This occurs because the supply of electrical power to the solenoid of the RAT ground retraction module is stopped. The RAT ground retraction module goes to the flight position and the RAT extends because of the ejection jack spring pressure.
Also the RAT will not retract but return to its fully extended position when the RAT retract lock does not engage. If the marks on the turbine hub and the leg are not aligned and the STOW/RESET switch is set to STOW, the RAT will start to retract but:
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：A320飞机维护手册 AMM HYDRAULIC POWER 液压5(103)
