# SDR USAASA0373

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: June 29, 2003
- Submitted: July 22, 2003
- Operation: Air carrier
- Aircraft: N164UW
- Make and model: Airbus A321-211
- Registry model: [Airbus A321-211](https://openairdocs.org/model/airbus-a321-211) (OpenAirDocs)
- Aircraft serial: 1425
- System (JASC): [3350 · Emergency Lighting](https://openairdocs.org/jasc/3350)
- Part: Battery
- Part number: 321430
- Condition: Inoperative
- Location: Emergency Light
- Stage of operation: IN
- How discovered: 9
- Nature of condition: L
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/USAASA0373

## Discrepancy

AIRCRAFT FAILED THE EMERGENCY LIGHT SYSTEM TEST, WITH A 'EPSU AFT L' MESSAGE.  MAINTENANCE REPLACED BATTERIES FOR THE AFT LEFT EMERGENCY POWER SUPPLY UNIT (13WL).  OPERATIONALLY CHECKS OK.  (M)

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