Description (AMM 31-24-01)

 

A- All data to be recorded is sent to the FDAU. The FDAU processes and prepares all data for recording. Electronic circuits in the FDAU provide isolation, signal preconditioning, multiplexing, scaling, synchronization, and converting the various input signal forms to a digital format. Selected signals are then sent to the FDR for recording.

 

B- The FDAU supplies 28 volts DC to the accelerometer.

 

C- SFIM FDAU

(1) The front panel of the FDAU has three LED fault indicators: DM FAULT, DFDAU FAULT, and DFDR FAULT. It also has a test set plug.

 

D- Teledyne FDAU

(1) The front panel of the FDAU has a READ switch, an ATE connector, fault lights and a fault STATUS display.

 

(a) The READ switch is used to provide a confidence test of the FDAU.

 

(b) The ATE connector allows connection to external test equipment.

 

(c) The STATUS display shows FDAU fault codes.

 

(d) The fault lights provide indication of the status of the system.

 

1) The FDAU FAIL light comes on if the internal FDAU tests fail.

 

2) The DFDR FAIL light comes on if the MAINTENANCE FLAG lin from the DFDR indicates a failed DFDR. The DFDR FAIL ligh also comes on if the flight recorder system is energize (FLIGHT RECORDER AC and FLIGHT RECORDER DC circuit breaker are closed) and the DFDR is not in operation (airplane o ground, both engines off, flight recorder TEST/NORMAL switch is in the NORMAL position).

 

3) The CAUTION light comes on if the internal checks of the non-mandatory part of the FDAU fail. The CAUTION light also comes on if the playback data is not present or not correct. The playback data will not be present if the FDR is not in operation.