# SDR 2003UALA00693

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 17, 2003
- Submitted: October 21, 2003
- Operation: Air carrier
- Aircraft: N335UA
- Make and model: Boeing 737322
- Aircraft serial: 24230
- Aircraft time: 44,646 hours, 23,685 cycles
- Engine: Ge CFM56*
- System (JASC): [2460 · DC Power Distribution System](https://openairdocs.org/jasc/2460)
- Part: Circuit Breaker
- Condition: Failed
- Location: Cabin Pressure
- Stage of operation: CR
- How discovered: O
- Nature of condition: G
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2003UALA00693

## Discrepancy

LANDED MCI UNDER AMBER ALERT DUE TO ELECTRICAL AND PRESSURIZATION PROBLEMS. FOUND NR 1 TRANSFER NORMAL CIRCUIT BREAKER POPPED.  COULD NOT DUPLICATE PROBLEM ON THE GROUND DURING TROUBLESHOOTING.  REPLACED CIRCUIT BREAKERS C819, C826, C806, AND NR 1 TRANSFER UNIT.  BASED ON PREVIOUS HISTORY THE NR 1 TRANSFER NORMAL CIRCUIT BREAKER (C819) IS SUSPECT AS THE CAUSE OF THE PROBLEM.

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