# SDR ASAA2015122114383

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: December 21, 2015
- Submitted: December 23, 2015
- Operation: Air carrier
- Aircraft: [N593AS](https://openairdocs.org/aircraft/N593AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35107
- Aircraft time: 29,868 hours, 9,206 cycles
- System (JASC): [4940 · APU Start/Ignition System](https://openairdocs.org/jasc/4940)
- Part: Exciter
- Part number: 38880587
- Part serial: 141051
- Condition: Failed
- Location: Apu
- Part time: 119 hours, 246 cycles
- Stage of operation: NR
- How discovered: 9
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2015122114383

## Discrepancy

APU WILL NOT START. FAULT LIGHT ILLUMINATED.  ACFT GROUNDED.  APU BITE TEST SHOWS FAULT CODE 49-41180, IGNITION CIRCUIT SHOWS HIGH CURRENT.  REPLACED THE APU IGNITION UNIT IAW AMM 49-41-31 AND FIM 49-40, TASK 804.  OPS CHECK GOOD WITH 4 SUCCESSFUL STARTS.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.