# SDR ASAA2021112736736

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: November 27, 2021
- Submitted: November 30, 2021
- Operation: Air carrier
- Aircraft: [N915AK](https://openairdocs.org/aircraft/N915AK), registered now
- Make and model: Boeing 737-9
- Registry model: [Boeing 737-9](https://openairdocs.org/model/boeing-737-9) (OpenAirDocs)
- Aircraft serial: 44080
- Aircraft time: 1,567 hours, 573 cycles
- System (JASC): [4940 · APU Start/Ignition System](https://openairdocs.org/jasc/4940)
- Part: Converter
- Part number: 51090360001
- Part serial: 5109036001565
- Condition: Faulty
- Location: E/E Rack E2-2
- Part time: 871 hours, 254 cycles
- Stage of operation: LD
- 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/ASAA2021112736736

## Discrepancy

AFTER LANDING, APU FAILED TO START. APU FAULT ILLUMINATED. GROUNDED - YES. FOUND FAULT 49-41254 ACTIVE BEFORE START SUCCESSFUL. FOUND FAULT 49-41012 REPEAT INSTANCES. CW B737-9 IFIM 49-40-00-810-805 AND 49-40-00-810-818. REMOVED AND REPLACED START CONVERTER UNIT GROUND VERIFICATION CHECK GOOD REF B737-9 AMM 49-41-61-400-801.

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