DOC AIRBUS | AMM A320FTHRUST REVERSER - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The fan thrust reverser is located immediatly downstream of the fan frame.
An adaptor ring attached to the rear engine fan frame interfaces between the engine and the reverser itself.
The fan thrust reverser is located immediatly downstream of the fan frame.
Thrust Reverser Component LocationAn adaptor ring attached to the rear engine fan frame interfaces between the engine and the reverser itself.
A. Direct thrust configuration
In direct thrust configuration, the cowling masks the blocker doors, thus providing fan flow ducting with minimized thrust loss.
In direct thrust configuration, the cowling masks the blocker doors, thus providing fan flow ducting with minimized thrust loss.
B. Reverse thrust configuration
In reverse thrust configuration, the blocker doors are deployed in order to obstruct the fan duct ; the fan flow is rejected laterally through the reverser with a forward velocity component which provides the reverse thrust.
The reverse mode is controlled and indicated in the cockpit (Ref. AMM D/O 78-31-00-00).
The reverse mode is hydraulically actuated after cockpit command.
The reverse thrust mode is only operative on ground
In reverse thrust configuration, the blocker doors are deployed in order to obstruct the fan duct ; the fan flow is rejected laterally through the reverser with a forward velocity component which provides the reverse thrust.
The reverse mode is controlled and indicated in the cockpit (Ref. AMM D/O 78-31-00-00).
The reverse mode is hydraulically actuated after cockpit command.
The reverse thrust mode is only operative on ground
2. Description
To give access to the engine, the reverser consists of two half-fan ducts cowls (D - ducts) hinged at pylon and latched at the bottom. The cowl opening system is used for maintenance purpose only. It is hydraulically actuated and composed of an actuator on each cowl, a hydraulic junction box and the associated pipings (Ref. AMM D/O 78-36-00-00).
The thrust reverser includes:
** ON A/C NOT FOR ALL To give access to the engine, the reverser consists of two half-fan ducts cowls (D - ducts) hinged at pylon and latched at the bottom. The cowl opening system is used for maintenance purpose only. It is hydraulically actuated and composed of an actuator on each cowl, a hydraulic junction box and the associated pipings (Ref. AMM D/O 78-36-00-00).
The thrust reverser includes:
- two blocker doors on each cowl, acoustic linings, a pressure relief system and fire walls (Ref. AMM D/O 78-32-00-00).
- LP turbine case and core compartment cooling systems (Ref. AMM D/O 75-00-00-00).
- a thrust reverser system composed of :
(Ref. AMM D/O 78-36-00-00) - a hydraulic control unit (HCU) with:
a pressurizing valve
a directional valve
a pressure switch
a flow limiter
a filter and clogging indicator
a bleed valve
a check valve restrictor
a mechanical inhibition - associated to each four pivoting blocker doors:
an actuator including secondary lock
a stow switch
a deploy switch
a primary lock - and associated piping and electrical harnesses
- a Shut-Off Valve (SOV) and associated filter (located in the pylon)
3. Operation
A. Thrust Reverser Stow Position
(1) When the thrust reverser function is not selected the thrust reverser blocker doors are locked stowed.
Four locks, one per blocker door locks the doors in the stowed position and assure the primary lock.
A redundant secondary lock is provided for stowed position by a system of claws inside each blocker door actuators.
The thrust reverser system using hydraulic power for stowing or deploying sequence is isolated and depressurized through the HCU and the SOV. The depressurisation is checked by the HCU pressure switch.
The stow and lock position is checked on each blocker door by a stow switch. Each switch is dual and includes two cells, one dedicated to each channel of the HCU.
Four locks, one per blocker door locks the doors in the stowed position and assure the primary lock.
A redundant secondary lock is provided for stowed position by a system of claws inside each blocker door actuators.
The thrust reverser system using hydraulic power for stowing or deploying sequence is isolated and depressurized through the HCU and the SOV. The depressurisation is checked by the HCU pressure switch.
The stow and lock position is checked on each blocker door by a stow switch. Each switch is dual and includes two cells, one dedicated to each channel of the HCU.
(2) Autorestow
The autorestow function is activated by the ECU to close and lock the thrust reverser blocker doors in case of abnormal unstowed position detection. This function is active only on ground and can be commanded only twice.
The autorestow function is activated by the ECU to close and lock the thrust reverser blocker doors in case of abnormal unstowed position detection. This function is active only on ground and can be commanded only twice.
B. Thrust reverser deploy sequence
Deploy sequence is only allowed on ground after actuation of the throttle control lever and requires actuation logic:
Deploy sequence is only allowed on ground after actuation of the throttle control lever and requires actuation logic:
- One ECU channel operating with its associated throttle reverse signal.
- SOV opening through the SEC and the static relay.
- Main gear compressed signal from at least one LGCIU.
- Throttle lever angle (TLA) reverse signal from at least one second.
Before the transit completion, the ECU sets the reverse idle thrust.
Deploy sequence after actuation logic passed: - The ECU allows the opening of HCU pressurizing valve and pressurizes the HCU while the SOV is opened through the SEC and the static relay.
- The HCU pressure switch sends a HCU pressurized signal to the ECU.
- The EIU and the ECU allow the opening of the HCU directional valve and pressurize the first primary lock.
- The primary locks are released in sequence.
- Consequently stow switches sends to the ECU an unstowing information signal.
After primary locks disengagement , the HCU provides the actuators with the hydraulic power. - The secondary locks included in each actuator are released.
- The actuators deploy the pivoting blocker doors.
- The deploy switches send to the ECU a full deployment information signal.
- When the deploy switches are pressed the ECU closes the HCU pressurizing valve to prepare the stow sequence and allows Max reverse thrust to be applied.
C. Thrust Reverser Stow Sequence
Once the four deploy switches are pressed the ECU closes the HCU pressurizing valve in order to prepare the stow sequence by arming the primary locks.
According to the new throttle control lever position, the SOV is closed through the SEC and the static relay.
According to the new throttle control lever position, the ECU commands the stow sequence as follows:
Once the four deploy switches are pressed the ECU closes the HCU pressurizing valve in order to prepare the stow sequence by arming the primary locks.
According to the new throttle control lever position, the SOV is closed through the SEC and the static relay.
According to the new throttle control lever position, the ECU commands the stow sequence as follows:
- The ECU sets the thrust power to idle during transit.
- The ECU closes the HCU directional valve and opens the HCU pressurizing valve to provide pressure only to the retract side of the blocker doors actuators.
- The actuators stow the blocker doors.
- The secondary and primary locks are engaged and locked.
- The stow switches send to the ECU a stowing information signal.
- The ECU closes the HCU pressurizing valve. The pressure is removed from the system.