# SDR ASAA2021020334012

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 3, 2021
- Submitted: February 6, 2021
- Operation: Air carrier
- Aircraft: [N431AS](https://openairdocs.org/aircraft/N431AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 43255
- Aircraft time: 27,531 hours, 8,883 cycles
- System (JASC): [4940 · APU Start/Ignition System](https://openairdocs.org/jasc/4940)
- Part: Generator
- Part number: 28B5459STYLEA
- Part serial: 128B1526
- Condition: Inoperative
- Location: Apu Bay
- Part time: 19,387 hours, 27,393 cycles
- Stage of operation: NR
- How discovered: O
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2021020334012

## Discrepancy

TWO ATTEMPTS TO START APU RESULTED IN TWO APU FAULTS, NO START.  GROUNDED - YES.  R & R STARTER-GENERATOR IAW B737-900 AMM 49-41-21 REF B737-900 FIM 49-40 TASK 803.  APU OPS AND LEAK CHECKED GOOD.  STARTER-GENERATOR PART NUMBER VERIFIED.  REF DEFECT 60035943 FOR MEL 49-99A.  REMOVED MEL PLACARDS.

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