DOC AIRBUS | AMM A320FTHRUST REVERSER INDEPENDENT LOCKING SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. System Description
The electrical tertiary lock system is an electro-mechanical lock for the Thrust Reverser Actuation System (TRAS). The tertiary lock system is the third system for the prevention of accidental movement of the translating cowl to the deployed (reverse thrust) position. The tertiary lock system is installed on the left latch beam of the thrust reverser at the 6 o'clock position. The tertiary lock system is controlled directly from the aircraft, and is continuously monitored by two single-channel proximity sensors. The proximity sensors transmit signals on channels A and B to the Electronic Engine Control (EEC) to show the tertiary lock system lock status (locked or unlocked). When electric power is applied, the tertiary lock system unlocks which permits the translating cowl to move to the deployed position.
The tertiary lock system has five primary components which are:
Removal of electric power causes the tertiary lock system to automatically go back to the ACTIVE condition. In the active condition, the tertiary lock system will lock the transcowl in the stowed position.
** ON A/C NOT FOR ALL The electrical tertiary lock system is an electro-mechanical lock for the Thrust Reverser Actuation System (TRAS). The tertiary lock system is the third system for the prevention of accidental movement of the translating cowl to the deployed (reverse thrust) position. The tertiary lock system is installed on the left latch beam of the thrust reverser at the 6 o'clock position. The tertiary lock system is controlled directly from the aircraft, and is continuously monitored by two single-channel proximity sensors. The proximity sensors transmit signals on channels A and B to the Electronic Engine Control (EEC) to show the tertiary lock system lock status (locked or unlocked). When electric power is applied, the tertiary lock system unlocks which permits the translating cowl to move to the deployed position.
The tertiary lock system has five primary components which are:
- Solenoid
- Proximity Sensors
- Activation/Deactivation Lever
- Hook
- Roller.
Electrical Tertiary Lock SystemRemoval of electric power causes the tertiary lock system to automatically go back to the ACTIVE condition. In the active condition, the tertiary lock system will lock the transcowl in the stowed position.
2. Deployed Operation
When the EEC transmits a signal to deploy to the TRAS, the tertiary lock system solenoid energizes and unlocks. The single-channel proximity sensors sense when the lever target is away and transmit a signal that the tertiary lock system is unlocked. The two proximity sensors are monitored by their EEC channels. The roller moves to the deployed position with the transcowl.
** ON A/C NOT FOR ALL When the EEC transmits a signal to deploy to the TRAS, the tertiary lock system solenoid energizes and unlocks. The single-channel proximity sensors sense when the lever target is away and transmit a signal that the tertiary lock system is unlocked. The two proximity sensors are monitored by their EEC channels. The roller moves to the deployed position with the transcowl.
3. Stow Operation
When the EEC transmits a signal that the TRAS is stowed, the tertiary lock system solenoid de-energizes and locks. The single-channel proximity sensors sense when the lever target is near and transmit a signal that the tertiary lock system is locked (de-energized and stowed). The two proximity sensors are monitored by their EEC channels. The roller moves to the stowed position with the transcowl.
** ON A/C NOT FOR ALL When the EEC transmits a signal that the TRAS is stowed, the tertiary lock system solenoid de-energizes and locks. The single-channel proximity sensors sense when the lever target is near and transmit a signal that the tertiary lock system is locked (de-energized and stowed). The two proximity sensors are monitored by their EEC channels. The roller moves to the stowed position with the transcowl.
4. Proximity Sensors
The two single-channel proximity sensors on the tertiary lock system each have one channel connected to the EEC. The proximity sensor target transmits a lock indication to the proximity sensors to show tertiary lock system lock status.
The proximity sensors are Line Replaceable Units (LRUs), and there are no adjustment procedures for the sensors or the target.
** ON A/C NOT FOR ALL The two single-channel proximity sensors on the tertiary lock system each have one channel connected to the EEC. The proximity sensor target transmits a lock indication to the proximity sensors to show tertiary lock system lock status.
The proximity sensors are Line Replaceable Units (LRUs), and there are no adjustment procedures for the sensors or the target.
5. Solenoid
The solenoid is used to move the lock lever and to release the hook. The solenoid has a single channel to release the lock mechanism and let the transcowl deploy.
** ON A/C NOT FOR ALL The solenoid is used to move the lock lever and to release the hook. The solenoid has a single channel to release the lock mechanism and let the transcowl deploy.
6. Activation/Deactivation Lever
The activation/deactivation lever is a mechanism to lock the tertiary lock system hook in the ACTIVE or UNLOCKED positions. When in the UNLOCKED position, the tertiary lock system will be unlocked at all times. When in the ACTIVE position, the hook will lock the transcowl the next time the transcowl moves to the stowed position. Personnel who operate the lever must make sure that the lever is fully engaged in one of the two positions.
** ON A/C NOT FOR ALL The activation/deactivation lever is a mechanism to lock the tertiary lock system hook in the ACTIVE or UNLOCKED positions. When in the UNLOCKED position, the tertiary lock system will be unlocked at all times. When in the ACTIVE position, the hook will lock the transcowl the next time the transcowl moves to the stowed position. Personnel who operate the lever must make sure that the lever is fully engaged in one of the two positions.
7. Hook
The hook is the structural item that engages with the roller to prevent accidental deployment of the translating cowl. Force is only applied to the hook if the thrust reverser tries to accidentally deploy.
The hook is the structural item that engages with the roller to prevent accidental deployment of the translating cowl. Force is only applied to the hook if the thrust reverser tries to accidentally deploy.