# SDR YENA2025072300753

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 21, 2025
- Submitted: July 23, 2025
- Operation: Air carrier
- Aircraft: [N4077J](https://openairdocs.org/aircraft/N4077J), registered now
- Make and model: Airbus A321-271NX
- Registry model: [Airbus A321-271NX](https://openairdocs.org/model/airbus-s-a-s-a321-271nx) (OpenAirDocs)
- Aircraft serial: 11604
- Aircraft time: 6,379 hours, 987 cycles
- System (JASC): [4940 · APU Start/Ignition System](https://openairdocs.org/jasc/4940)
- Part: Apu
- Condition: Malfunctioned
- Location: Zone 100
- 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/YENA2025072300753

## Discrepancy

FLT#834, SFO-BOS. (ETOPS)  APU FAILED TO START IAW A49-00-01A 2 START ATTEMPS MADE OAT- 44 FL350; REMOVED AND REPLACED APU IGNITION EXCITER REF AMM 49-41-38 OPS CHECK GOOD.

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