Each engine is equipped with a thrust reverser system that reduces stopping distance and brake disc wear. The T/R’s reverse the fan airflow forward through blocker doors, cascades and translating sleeves
The left T/R uses hydraulic system A and the right, system B where they both are able to receive standby hydraulic pressure when their respective hydraulic system is unserviceable. Note that T/R use with standby pressure is of a lesser rate so, losing one main hydraulic system will operate that side slower than with main system pressure creating a possible swerve during reverser action.
The T/R’s are controlled by the T/R levers on the thrust levers and operate when < 10 ft. RA or on the ground. The T/R operates when the thrust lever is at the Idle position and the T/R handle is lifted to the interlock position when the isolation valve positions to deploy the “translating sleeves”. The EEC’s determine through a Linear variable differential transformer (LVDT) a 60% opening of the two sleeves on each T/R, where after the mechanical interlock releases and the levers can be lifted further to the Detent 1, 2 or MAX position.
When the sleeves move, the CDS shows the next message on the Upper DU.
• Amber REV when deploying or stowing
• Green REV when fully deployed
When stowing the T/R’s, the stow command is initiated by passing the 1 Detent position which commands the T/R sleeves to stow. When the T/R lever is full down and the sleeves at the 0%
(closed) position, the isolation valve closes and the locks engage.
During normal operation the amber REVERSER light on the engine control panel illuminates for 10 seconds without a MASTER CAUTION during a T/R stow operation and extinguishes when the locks are engaged. The light will stay illuminated if the T/R does not stow in 10 seconds, indicating a malfunction.
When the light illuminates for more than 12 seconds a malfunction is detected and the ENG annunciator and MASTER CAUTION light illuminates.
When the down motion of the T/R levers is delayed for more than 18 seconds, the ENG annunciator and MASTER CAUTION light illuminate and the locks will engage, preventing further movement of the sleeves. To clear this situation you can cycle the levers to the interlock position and back down.
When a serious malfunction or disagree exists between the LVDT’s, the ENGINE CONTROL light illuminates on the engine control panel together with a MASTER CAUTION. When illuminated, it could mean a serious engine (EEC) malfunction or an LVDT malfunction/disagree, when illuminated do not dispatch the aircraft.
Each T/R T/R depl (AMM) m
An auto–
it determ position, and the
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installing two for flight disp R’s.
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