ATA 77 - ENGINE INDICATING

• This sensor is an induction type tachometer. It consists of 3 independent sensing elements which are magnetically and electrically insulated from each other. (phonic wheel 29 tooth)

• This sensor is an induction tachometer type. It comprises 3 sensitive elements. Each element is magnetically and electrically isolated from the other. (71 tooth)

• The engine Exhaust Gas Temperature (EGT) is sensed and averaged by 9 thermocouple probes (chromel/alumel) located in the T49.5 plane of Low PressureTurbine (LPT) stage 2 nozzle assembly.

• Number 1 Bearing accelerometer, normal pick-up, provides N1 and N2 vibration frequencies. Sends data to EVMU (Engine Vibration Monitoring Unit).

• The Turbine Rear Frame (TRF) accelerometer is in standby and is also used with the first to analyses results for engine balancing.

• Only one accelerometer is used at any particular time. The second accelerometer is selected manually via MCDU “ACC. RECONFIGURATION” menu or automatically at the next power up due to a failure of the N1 BEARING ACCEL.

• An Engine Vibration Monitoring Unit monitors the N1 and N2 levels of both engines. (It monitors vibration via number 1 BEARING

ACCELEROMETER).

• We have a single EVMU for both Engines.

• DMCs (Data Management Computer) calculate USED FUEL, while ECUs (Electronic Control Unit) compute FUEL FLOW.

• “REV” indication is showed only when the reversers are open, not fully stowed or when the pivoting doors are not closed correctly. “REV” amber indication appears on the related engine N1 dial on ECAM EWD.

• ECU(1,2) CH.A is powered by DC ESS BUS, then when ENGs are running (N2 > 12%) ECU will be powered by its own generator (located

in the Accessory Gear Box)

• N1 and N2 Sensors:

- N1 sensor has 3 independent sensing elements (ECU CH.A, ECU CH.B, EVMU)

- N2 sensor has 3 independent sensing elements (ECU CH.A, ECU CH.B, EVMU)