DOC AIRBUS | AMM A320FT/R OPENING MECHANISM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The thrust reverser Door Opening System (DOS) opens the thrust reverser assembly and supplies access to the engine core for ground maintenance. The DOS includes an actuator and a Hold Open Rod (HOR).
** ON A/C NOT FOR ALL The thrust reverser Door Opening System (DOS) opens the thrust reverser assembly and supplies access to the engine core for ground maintenance. The DOS includes an actuator and a Hold Open Rod (HOR).
2. System Description
Thrust Reverser Door Opening System (DOS)A. Actuator
The DOS has a Corrosion Resistant Steel (CRES) and aluminum hydraulic actuator which opens and closes the thrust reverser. The actuator also gives support to the thrust reverser in the open and locked position. The actuator is located in the fan compartment and attaches to the engine fan case and the torque box of the thrust reverser. The actuator includes the following components:
The DOS has a Corrosion Resistant Steel (CRES) and aluminum hydraulic actuator which opens and closes the thrust reverser. The actuator also gives support to the thrust reverser in the open and locked position. The actuator is located in the fan compartment and attaches to the engine fan case and the torque box of the thrust reverser. The actuator includes the following components:
- Actuator body
- Accumulator assembly
- Quick disconnect.
(1) Actuator Body
The actuator body has a piston rod and a chamber for hydraulic fluid. The actuator body has a bearing at the cylinder end that attaches to the engine fan case. On the opposite end, there is a breather housing filter which allows bleeding of air during extension and retraction of the actuator. A piston inside the actuator transfers the force to open and close the thrust reverser The piston has a rod end with a spherical bearing that attaches to the torque box.
The actuator body has a piston rod and a chamber for hydraulic fluid. The actuator body has a bearing at the cylinder end that attaches to the engine fan case. On the opposite end, there is a breather housing filter which allows bleeding of air during extension and retraction of the actuator. A piston inside the actuator transfers the force to open and close the thrust reverser The piston has a rod end with a spherical bearing that attaches to the torque box.
(2) Accumulator Assembly
The accumulator assembly absorbs pressure due to the effects of thermal expansion of hydraulic fluid. This prevents pressure from transferring to the engine fan case or the thrust reverser if the thrust reverser pump disconnects prematurely. If there is blockage of the filter of the breather housing and the actuator will not deploy, then a pressure relief valve in the accumulator prevents too much pressure in the actuator. The accumulator assembly also has a flow control valve. This valve controls the rate at which the thrust reverser closes. There is also a filter in the accumulator to prevent debris from entering the actuator hydraulic system.
The accumulator assembly absorbs pressure due to the effects of thermal expansion of hydraulic fluid. This prevents pressure from transferring to the engine fan case or the thrust reverser if the thrust reverser pump disconnects prematurely. If there is blockage of the filter of the breather housing and the actuator will not deploy, then a pressure relief valve in the accumulator prevents too much pressure in the actuator. The accumulator assembly also has a flow control valve. This valve controls the rate at which the thrust reverser closes. There is also a filter in the accumulator to prevent debris from entering the actuator hydraulic system.
(3) Quick Disconnect
The quick disconnect lets you attach the thrust reverser hand pump to the actuator.
The quick disconnect lets you attach the thrust reverser hand pump to the actuator.
B. Hold Open Rod (HOR)
The HOR supports the thrust reverser door at an angle of 45 degrees when the door is in the open position. The HOR assembly has an inner rod, an outer rod, a swivel end fitting, a lock hook and a locking collar. The swivel end fitting is attached to the upper bracket of the torque box. When stowed, the lock hook is attached to the lower bracket of the torque box. When the thrust reverser opens, the lock hook is disconnected from the lower bracket of the torque box, and then it is unlocked by rotating the locking collar so that you can extend the inner rod. The locking hook connects to a receiver pin on the lower bracket of the fan case and then it is rotated to the lock position to support the thrust reverser.
The HOR supports the thrust reverser door at an angle of 45 degrees when the door is in the open position. The HOR assembly has an inner rod, an outer rod, a swivel end fitting, a lock hook and a locking collar. The swivel end fitting is attached to the upper bracket of the torque box. When stowed, the lock hook is attached to the lower bracket of the torque box. When the thrust reverser opens, the lock hook is disconnected from the lower bracket of the torque box, and then it is unlocked by rotating the locking collar so that you can extend the inner rod. The locking hook connects to a receiver pin on the lower bracket of the fan case and then it is rotated to the lock position to support the thrust reverser.
3. Operation/Control and Indicating
The thrust reverser hand pump is connected to the quick disconnect of the DOS actuator. When hydraulic fluid in the hand pump is pressurized, it flows into the accumulator. At the same time the hydraulic fluid flows into the actuator through the flow control valve and causes the actuator to extend. With the thrust reverser fully open and hydraulic fluid supply from the hand pump, the pressure relief valve opens and lets the hydraulic fluid flow from the vent hole in the accumulator assembly. This prevents over-pressurization of the actuator. The hydraulic pressure within the actuator holds the thrust reverser in the open position while the HOR is connected. Once the HOR is connected and locked, the actuator is depressurized. The actuator is pressurized again to take up the load of the thrust reverser allowing the HOR to be disconnected and stowed. To close the thrust reverser, the actuator is depressurized by allowing the fluid to flow through the flow control valve that controls the rate of closure time. The hand pump is disconnected from the quick disconnect of the DOS actuator.
The thrust reverser hand pump is connected to the quick disconnect of the DOS actuator. When hydraulic fluid in the hand pump is pressurized, it flows into the accumulator. At the same time the hydraulic fluid flows into the actuator through the flow control valve and causes the actuator to extend. With the thrust reverser fully open and hydraulic fluid supply from the hand pump, the pressure relief valve opens and lets the hydraulic fluid flow from the vent hole in the accumulator assembly. This prevents over-pressurization of the actuator. The hydraulic pressure within the actuator holds the thrust reverser in the open position while the HOR is connected. Once the HOR is connected and locked, the actuator is depressurized. The actuator is pressurized again to take up the load of the thrust reverser allowing the HOR to be disconnected and stowed. To close the thrust reverser, the actuator is depressurized by allowing the fluid to flow through the flow control valve that controls the rate of closure time. The hand pump is disconnected from the quick disconnect of the DOS actuator.