# SDR ASAA2019103081176

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 28, 2019
- Submitted: October 30, 2019
- Operation: Air carrier
- Aircraft: [N419AS](https://openairdocs.org/aircraft/N419AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 41734
- Aircraft time: 26,268 hours, 8,519 cycles
- System (JASC): [4970 · APU Indicating System](https://openairdocs.org/jasc/4970)
- Part: Module
- Condition: Faulted
- Location: Apu
- Stage of operation: CR
- How discovered: O
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2019103081176

## Discrepancy

APU CSS FAILED FL350, FL350 AND FL310. APU FAULT LIGHT ILLUMINATED. APU OPERATES NORMALLY ON THE GROUND. GROUNDED - YES. PREFORMED APU BITE FOUND FAULT MSG 49-72104 DMM MODULE FAULT, PREFORMED APU START ON GND PER B737-900 AMM 49-11-00 APU START NORMAL, NO FAULT NOTED OK FOR SERVICE.

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