# SDR K11A2025040200309

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 2, 2025
- Submitted: April 2, 2025
- Operation: Air carrier
- Aircraft: [N337CK](https://openairdocs.org/aircraft/N337CK), registered now
- Make and model: Boeing 737-3Y0
- Registry model: [Boeing 737-3Y0](https://openairdocs.org/model/boeing-737-3y0) (OpenAirDocs)
- Aircraft serial: 25173
- Aircraft time: 56,690 hours, 40,556 cycles
- System (JASC): [3510 · Crew Oxygen System](https://openairdocs.org/jasc/3510)
- Part: Oxygen Mask
- Condition: Inoperative
- Location: Zone 200
- Stage of operation: DE
- 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/K11A2025040200309

## Discrepancy

FO SIDE OXYGEN MASK BECAME INOPERATIVE AFTER 2 MINUTES OF USE.  EMERGENCY PROCEDURE (DESCRIBE UNSCHEDULED LANDING, EMER. DESCENT, ETC) TEXT: FO SWITCHED TO AN ADDITIONAL MASK IN THE COCKPIT.  REATTACHED FO’S OXYGEN MASK HOSE IAW B737 AMM 35-12-86. PERFORMED OPS CHECK AND LEAK CHECK IAW B737 AMM 35-12-00 AND LEAK CHECK GOOD NO DEFECTS NOTED.

---
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.