# SDR CALA2026031014459

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: March 3, 2026
- Submitted: March 10, 2026
- Operation: Air carrier
- Aircraft: [N34551](https://openairdocs.org/aircraft/N34551), 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: 12817
- Aircraft time: 871 hours, 339 cycles
- System (JASC): [3350 · Emergency Lighting](https://openairdocs.org/jasc/3350)
- Part: Power Supply
- Condition: Failed
- Location: Zone 200
- Stage of operation: NR
- 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/CALA2026031014459

## Discrepancy

CIDS 1 EPSU SYS TEST SHOWS "EPSU (12WL) EXT R" MESSAGE. TEST OF THE EPSU SHOWS "UNIT FAILED" FAULT. R & R THE EPSU BATTERIES TWICE. NO GOOD. INSPECTED FOR BURNT OUT LIGHTS. ALL EMERGENCY LIGHTS OPERATIONAL. RESEATED CONNECTOR PLUG. NO GOOD. NO ECAM MESSAGE. ENTIRE EPSU UNIT NEEDS REPLACEMENT. PANEL FOR UNIT REMAINS OPEN FOR MAINTENANCE.   REMOVED AND REPLACED EPSU FIN 12WL IAW AMM 33-51-38-400-001-A. ALL BITE AND LEARN IN PROGRAMMING OPS CK NORMAL. PERF CIDS INTERFACE AND POWER UP TEST REF AMM 23-73-00-740-005-B. TEST OK. OK TO CONTINUE.  REF LP 8095930 FOR BORROWED PART TRANSACTION AND CARRY.

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