# SDR UIEA2025040400438

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 4, 2025
- Submitted: April 8, 2025
- Operation: Air carrier
- Aircraft: [N489MC](https://openairdocs.org/aircraft/N489MC), registered now
- Make and model: Boeing 747412F
- Aircraft serial: 26553
- Aircraft time: 117,650 hours, 20,556 cycles
- System (JASC): [3510 · Crew Oxygen System](https://openairdocs.org/jasc/3510)
- Part: Transducer
- Part number: 10015748
- Condition: Malfunctioned
- Location: Zone 100
- Stage of operation: CR
- How discovered: O
- Nature of condition: O
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UIEA2025040400438

## Discrepancy

CREW SUSPECTED O2 LEAK DUE TO O2 QUANTITY DECREASING APPROX 10 PSI PER 20 MIN DURING FLIGHT. AHM SHOWED CREW O2 LOW MESSAGE.(<P>VERIFIED NO CREW O2 LEAKS AND PRESSURE CHECK OKAY AT 1720 PSI. TRANSFER INDICATION TO MDDR #228611 PER MEL 35-11-02 CAT C DUE 14APR25. C/W MX ACTION.</P> / <P>REMOVED AND REPLACED UPPER CREW SYSTEM PRESSURE TRANSDUCER IAW AMM 35-41-08. OPS AND LEAK CHECK GOOD. DMI 228611 CLEARED.

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