Reverse
Thrust System
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The reverse thrust system provides means of decelerating aircraft during the landing roll, thus reducing landing roll length. The thrust reverser units are attached at the turbine outlet case of each engine. The clamshell door type thrust reverser provides reversal of thrust by blocking the engine exhaust gas and fan air flow and deflecting the gasses through openings made by repositioned defector doors or by fixed cascade vane openings depending on the type of reverser mechanism. Exhaust gases of the centre engine are defected forward and out of the sides of the aft fuselage, and on strut mounted engines gases are defected above and below the engine in a forward direction. The reversers are controlled by reverse thrust levers and operated by 13th stage engine bleed air. When not in use, the reversers are held in the locked position by 13th stage air and a mechanical lock. Each engine throttle has an additional handle which is used to actuate the thrust reversers. The reverse thrust lever pivots about a point near to the top of the throttle. If reverse trust is required, the throttle must be retarded to closed and then the reverse thrust lever must be pulled up. Further aft movement of the lever will increase reverse thrust. "Feel is built into the system by spring loads that increase as more reverse thrust is applied. Three amber thrust reverser operating lights are on the pilots centre instrument panel illuminate to indicate that the reverse thrust units are not locked in the forward thrust position. The have a dim facility.
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