# SDR ASAA2023071144012

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 11, 2023
- Submitted: July 17, 2023
- Operation: Air carrier
- Aircraft: [N963AK](https://openairdocs.org/aircraft/N963AK), registered now
- Make and model: Boeing 737-9
- Registry model: [Boeing 737-9](https://openairdocs.org/model/boeing-737-9) (OpenAirDocs)
- Aircraft serial: 44069
- Aircraft time: 889 hours, 281 cycles
- System (JASC): [4900 · Airborne Auxiliary Power Unit (APU) System](https://openairdocs.org/jasc/4900)
- Part: Unknown
- Part number: UNKNOWN
- Condition: Unknown
- Location: Unknown
- Stage of operation: IN
- How discovered: V
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2023071144012

## Discrepancy

APU FAULT LIGHT OCCURS WHEN PWR IS SUPPLIED VIA EITHER APU START SW OR APU TEST MODE. FOUND MAINT MSG 49-89002 NO INPUT FROM APU ECU. APU WILL NOT START. GROUNDED - YES. ON DEFERRAL.

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