DOC AIRBUS | AMM A320FTHRUST REVERSER INDEPENDENT LOCKING SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
An independent locking system is designed to isolate the thrust reverser from the aircraft hydraulic system. This system consists of thrust reverser Shut-Off Valve (SOV) upstream of the Hydraulic Control Unit (HCU), a filter and associated plumbing, mounting and electrical supply. The SOV is electrically actuated from an independent signal from the SEC (Spoiler Elevator Computer), bypassing the FADEC command circuit.
** ON A/C NOT FOR ALL An independent locking system is designed to isolate the thrust reverser from the aircraft hydraulic system. This system consists of thrust reverser Shut-Off Valve (SOV) upstream of the Hydraulic Control Unit (HCU), a filter and associated plumbing, mounting and electrical supply. The SOV is electrically actuated from an independent signal from the SEC (Spoiler Elevator Computer), bypassing the FADEC command circuit.
2. Component Location
The SOV and the filter are located under the pylon.
** ON A/C NOT FOR ALL The SOV and the filter are located under the pylon.
Shut-Off Valve and Filter Location| ------------------------------------------------------------------------------- |
| ! FIN ! FUNCTIONAL DESIGNATION ! PANEL ! ZONE ! ACCESS ! ATA ! |
| ! ! ! ! ! ! REF. ! |
| ------------------------------------------------------------------------------- |
| 50EG1 VALVE-THRUST REVERSER 410 437AL 78-37-51 |
| ISOLATION, ENG1 |
| 50EG2 VALVE-THRUST REVERSER 420 447AL 78-37-51 |
| ISOLATION, ENG2 |
| 3455KM1 FILTER-THRUST REVERSER 410 437AL 78-37-51 |
| ISOLATION VALVE, ENG1 |
| 3455KM2 FILTER-THRUST REVERSER 420 447AL 78-37-51 |
| ISOLATION VALVE, ENG2 |
A. Shut-Off Valve
The thrust reverser Shut-Off Valve (SOV) is a 3 port, two position spool valve. It is controlled by a solenoid driven 3 port, two position normally open pilot valve. Electrical power is supplied to the SOV through the fan electrical feeder box.
The thrust reverser Shut-Off Valve (SOV) is a 3 port, two position spool valve. It is controlled by a solenoid driven 3 port, two position normally open pilot valve. Electrical power is supplied to the SOV through the fan electrical feeder box.
B. Filter and Clogging Indicator
It is used to filter the fluid from the aircraft hydraulic system. The filter is a flow-through cartridge-type filter. The clogging indicator monitors the pressure loss through the filter cartridge and has a pop-out indicator to signal when it is necessary to replace the filter element. Two spring-loaded magnetic pistons keep the pop out indicator in retracted position. The lower magnetic piston monitors the differential between the filtered and unfiltered fluid pressure across the filter element. As the differential pressure increases, the piston compresses its spring and moves away from the upper magnetic piston. At a preset displacement of approximately 2 mm, the upper magnetic piston spring overcomes the magnetic force and drives the pop-out indicator from its retracted position.
The filter assembly contains a check valve to permit the removal of the canister and the change of the filter element with a minimum of spillage.
It is used to filter the fluid from the aircraft hydraulic system. The filter is a flow-through cartridge-type filter. The clogging indicator monitors the pressure loss through the filter cartridge and has a pop-out indicator to signal when it is necessary to replace the filter element. Two spring-loaded magnetic pistons keep the pop out indicator in retracted position. The lower magnetic piston monitors the differential between the filtered and unfiltered fluid pressure across the filter element. As the differential pressure increases, the piston compresses its spring and moves away from the upper magnetic piston. At a preset displacement of approximately 2 mm, the upper magnetic piston spring overcomes the magnetic force and drives the pop-out indicator from its retracted position.
The filter assembly contains a check valve to permit the removal of the canister and the change of the filter element with a minimum of spillage.
A. Shut-Off Valve Opening/Closing Operation
The hydraulic power for the thrust reverser operation is obtained from the engine driven pump of the hydraulic system (Ref. AMM D/O 29-10-00-00), which supplies the HCU through the filter and the thrust reverser SOV. The thrust reverser SOV is designed to isolate the thrust reverser from the aircraft hydraulic system. When the solenoid is de-energized the pilot and spool valves are pressure and spring driven to close the supply port. When the supply port is closed the thrust reverser is isolated from the aircraft hydraulic system. When the solenoid is energized the pilot valve releases the pressure from on the spool and opens a path to the return port. The sub-piston, which always has system pressure acting on it, will move the spool against the spring to open the control port. When the control port opens it allows the aircraft hydraulic fluid from the supply port to pass through the valve, exit the valve from the control port and enter the HCU.
The thrust reverser SOV is commanded in the open position when the following conditions are satisfied:
The hydraulic power for the thrust reverser operation is obtained from the engine driven pump of the hydraulic system (Ref. AMM D/O 29-10-00-00), which supplies the HCU through the filter and the thrust reverser SOV. The thrust reverser SOV is designed to isolate the thrust reverser from the aircraft hydraulic system. When the solenoid is de-energized the pilot and spool valves are pressure and spring driven to close the supply port. When the supply port is closed the thrust reverser is isolated from the aircraft hydraulic system. When the solenoid is energized the pilot valve releases the pressure from on the spool and opens a path to the return port. The sub-piston, which always has system pressure acting on it, will move the spool against the spring to open the control port. When the control port opens it allows the aircraft hydraulic fluid from the supply port to pass through the valve, exit the valve from the control port and enter the HCU.
The thrust reverser SOV is commanded in the open position when the following conditions are satisfied:
- aircraft is on ground proximity (less than 6 ft)
- reverse thrust is selected
- high forward thrust not selected on opposite engine