DOC AIRBUS | AMM A320FTHRUST REVERSER TERTIARY LOCKING SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The tertiary locks are a safety device that prevents accidental deployment of the thrust reverser during the flight. The actuators of the Thrust Reverser Actuation System (TRAS) have internal locks that automatically re-lock with hydraulic pressure when the actuators fully retract. If these internal locks fail, then the tertiary locks keep the translating sleeves in the stowed position.
** ON A/C NOT FOR ALL The tertiary locks are a safety device that prevents accidental deployment of the thrust reverser during the flight. The actuators of the Thrust Reverser Actuation System (TRAS) have internal locks that automatically re-lock with hydraulic pressure when the actuators fully retract. If these internal locks fail, then the tertiary locks keep the translating sleeves in the stowed position.
2. System Description
There are two tertiary locks, one on each thrust reverser half at the 6 o'clock position (when you look forward). A Tertiary Lock Valve (TLV) on the lower torque box controls the supply of hydraulic fluid to each tertiary lock. The TLV is external to the TRAS and independently controlled by a command from the aircraft. Each tertiary lock has two proximity switches which send a "lock" or "unlock" status to the Electronic Engine Control (EEC). There is also a lockout lever to deactivate or activate the tertiary locks for maintenance.
** ON A/C NOT FOR ALL There are two tertiary locks, one on each thrust reverser half at the 6 o'clock position (when you look forward). A Tertiary Lock Valve (TLV) on the lower torque box controls the supply of hydraulic fluid to each tertiary lock. The TLV is external to the TRAS and independently controlled by a command from the aircraft. Each tertiary lock has two proximity switches which send a "lock" or "unlock" status to the Electronic Engine Control (EEC). There is also a lockout lever to deactivate or activate the tertiary locks for maintenance.
Thrust Reverser Tertiary Locking System3. Operation/Control and Indicating
Once the TLV is commanded open by the aircraft, the solenoid on the TLV energizes and the blade on the tertiary lock moves to the unlocked position. The targets on the proximity sensors move to the "far" position. This allows the proximity sensors to send signals to the aircraft, indicating that the tertiary lock is unlocked and the thrust reverser can be deployed. When the tertiary lock receives supply pressure from the energized TLV, an internal piston retracts the blade and the tertiary locks unlock. Once the translating sleeve moves outside of the stowed position, the solenoid stays energized and the tertiary lock stays unlocked until the TRAS returns to the stowed position. When the TLV is de-energized, the track lock is in the locked position.
Once the TLV is commanded open by the aircraft, the solenoid on the TLV energizes and the blade on the tertiary lock moves to the unlocked position. The targets on the proximity sensors move to the "far" position. This allows the proximity sensors to send signals to the aircraft, indicating that the tertiary lock is unlocked and the thrust reverser can be deployed. When the tertiary lock receives supply pressure from the energized TLV, an internal piston retracts the blade and the tertiary locks unlock. Once the translating sleeve moves outside of the stowed position, the solenoid stays energized and the tertiary lock stays unlocked until the TRAS returns to the stowed position. When the TLV is de-energized, the track lock is in the locked position.