# SDR CALA2026030414302

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: March 4, 2026
- Submitted: March 4, 2026
- Operation: Air carrier
- Aircraft: [N77576](https://openairdocs.org/aircraft/N77576), registered now
- Make and model: Boeing 737-9
- Registry model: [Boeing 737-9](https://openairdocs.org/model/boeing-737-9) (OpenAirDocs)
- Aircraft serial: 67610
- Aircraft time: 8,803 hours, 2,879 cycles
- System (JASC): [2120 · Air Distribution System](https://openairdocs.org/jasc/2120)
- Part: Unknown
- Condition: Odor
- Stage of operation: NR
- How discovered: O
- Nature of condition: B
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CALA2026030414302

## Discrepancy

CHRONIC NGS DEGRADED. HISTORY FAULTS SHOWING 47-30063  PERFORM FIM 47-31 TASK 831, IF NO FAULTS FOUND, REPLACE O2 SENSOR & PERFORM DRAIN CAP FUEL LEAK CHECK REF AMM 47-21-00-700-801 IF SMELL FOUND COMPLETE TASK & REPLACE BACK FLOW CHECK VALVES & ASM DUE TO FUEL CONTAMINATION. IF NO FUEL FOUND. AFTER REPLACING O2 SENSOR. PERFORM SYSTEM FUNCTIONAL TEST TASK 47-00-00-720-801"ALT METHOD NGS BITE DISPLAY", TO VERIFY CORRECT OPERATION & TEMP. CLOSE THIS LOG AFTER C/W.

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