# SDR AALA202101149013

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 13, 2021
- Submitted: January 14, 2021
- Operation: Air carrier
- Aircraft: [N870AX](https://openairdocs.org/aircraft/N870AX), registered now
- Make and model: Boeing 787-8
- Registry model: [Boeing 787-8](https://openairdocs.org/model/boeing-787-8) (OpenAirDocs)
- Aircraft serial: 65990
- Aircraft time: 312 hours, 57 cycles
- System (JASC): [3350 · Emergency Lighting](https://openairdocs.org/jasc/3350)
- Part: Control Unit
- Part number: 100260103
- Condition: Faulted
- Location: Emergency Lights
- Stage of operation: IN
- How discovered: 9
- Nature of condition: J
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/AALA202101149013

## Discrepancy

AIRCRAFT WAS NOT GROUNDED.  UPON COMPLETION OF W/C 78C21033001 FOUND MESSAGE CLASS 01 DOOR 1 LT PRIME WELS CONTROL UNIT FAULT.  PERFORMED FIM DMC -B787-A-33-50-F1-37A-421A-A MAINTENANCE MESSAGE 33-11221.  REPLACED WELS CONTROL UNIT, IAW AMM B787-A-33-51-07-01A-520A-A/720A-A.

---
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.