# SDR WRNA201309270014

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 24, 2013
- Submitted: September 27, 2013
- Operation: Air carrier
- Aircraft: N953AR
- Make and model: Doug MD-11F
- Registry model: [Doug MD-11F](https://openairdocs.org/model/mcdonnell-douglas-md-11f) (OpenAirDocs)
- Aircraft serial: 48520
- Aircraft time: 61,652 hours, 15,804 cycles
- System (JASC): [2421 · AC Generator-Alternator](https://openairdocs.org/jasc/2421)
- Part: Gcu
- Part number: 976J86217
- Part serial: 022534A
- Condition: Faulted
- Location: Apu
- Part time: 1,696 hours, 445 cycles
- Stage of operation: CR
- How discovered: O
- Nature of condition: J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/WRNA201309270014

## Discrepancy

IN FLIGHT, LOST RT EMERGENCY AC BUSS, GEN BUS 3 FAULT ALERT.  FOLLOWED THE QRH PROCEDURES, DEPLOYED ADG AND RETURNED TO DEPARTURE WITHOUT FURTHER INCIDENT.  FOUND IDG/INTERFACE TRIM HEAD FAULT.  FOUND CONNECTOR "A" PINS 8 & 7 OPEN. REPINNED.  OPS CHECKED OK.  AFTER CHECK OUT, HAD NR 3 TRANSFORMER FAULT.  REPLACED NR 3 TR & GEN CONT RELAY, SWAP RELAY.  ALL NO HELP.  R2 APU GCU, NO FAULTS.

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