# SDR NWAA094246743

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: December 9, 2009
- Submitted: December 10, 2009
- Operation: Air carrier
- Aircraft: N643NW
- Make and model: Boeing 747249F
- Aircraft serial: 97217
- Aircraft time: 97,217 hours, 22,145 cycles
- System (JASC): [2611 · Smoke Detection](https://openairdocs.org/jasc/2611)
- Part: Smoke Detector
- Condition: Dirty
- Location: Main Deck
- Stage of operation: NR
- How discovered: O
- Nature of condition: N
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/NWAA094246743

## Discrepancy

IN FLIGHT, MASTER FIRE WARNING ILLUMINATED WITH FIRE BELL, AND THE MAIN DECK CARGO SMOKE DETECTOR NR 1 ILLUMINATED.  LIGHTS EXTINGUISHED AND BELL SILENCED PRIOR TO CHECKLIST COMPLETION.  VISUAL CHECK SHOWED NOTHING.  NO REOCCURRENCE DURING FLIGHT.  MAINTENANCE FOUND MAIN DECK SMOKE DETECTOR 1A DIRTY/DUSTY.  CLEANED DETECTOR.  SYSTEM TESTED OKAY.

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