# SDR UIEA2012072700333

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 27, 2012
- Submitted: July 30, 2012
- Operation: Air carrier
- Aircraft: [N409MC](https://openairdocs.org/aircraft/N409MC), registered now
- Make and model: Boeing 747-47UF
- Registry model: [Boeing 747-47UF](https://openairdocs.org/model/boeing-747-47uf) (OpenAirDocs)
- Aircraft serial: 30558
- Aircraft time: 53,695 hours, 8,040 cycles
- Engine: Ge CF680C2B1F
- System (JASC): [3520 · Passenger Oxygen System](https://openairdocs.org/jasc/3520)
- Part: Oxygen System
- Condition: Malfunctioned
- Stage of operation: CR
- How discovered: 9
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UIEA2012072700333

## Discrepancy

EICAS-SUPERNUMERARY OXYGEN ON.  MASKS DROPPED- NORM PRESSURE.  CABIN ALT 5300'.

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