# SDR DALA2025011300304

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 11, 2025
- Submitted: January 13, 2025
- Operation: Air carrier
- Aircraft: [N557NW](https://openairdocs.org/aircraft/N557NW), registered now
- Make and model: Boeing 757251
- Aircraft serial: 33393
- Aircraft time: 62,726 hours, 28,332 cycles
- System (JASC): [4990 · APU Oil System](https://openairdocs.org/jasc/4990)
- Part: Oil Cooler
- Condition: Failed
- Location: Apu
- Stage of operation: TX
- How discovered: O
- Nature of condition: J, B
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/DALA2025011300304

## Discrepancy

SHIP 5657 APU FAULT CAUTION AND APU SHUTDOWN AT GATE. THIS WAS ACCOMPANIED BY A BURNING ODOR. CORRECTIVE ACTION: BITE TEST OF APU SHOWS AUTO SHUTDOWN FOR HIGH OIL TEMP. REPLACED OIL COOLER BY-PASS VALVE PER B-757 AMM 49-27. FOUND AIR INLET DUCT FOR OIL COOLER COLLAPSED INTERNALLY. REPLACED APU OIL COOLER SUPPLY DUCT- APU OPN NML. (6917476)

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