# SDR 2026FA0000560

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 3, 2026
- Submitted: July 3, 2026
- Operation: General aviation
- System (JASC): [3340 · Exterior Lighting](https://openairdocs.org/jasc/3340)
- Part: Bulb
- Part number: NLI751224
- Condition: Burned Out
- Stage of operation: IN
- How discovered: V
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2026FA0000560

## Discrepancy

WE HAVE DISCOVERED THAT THE NAVIGATION LIGHT BULBS ARE OF VERY POOR QUALITY AND ARE NOT RELIABLE.  WE HAVE USED THESE BULBS IN THE PAST WITHOUT ISSUE, BUT THE PAST TWO BATCHES HAVE BEEN CONSISTENTLY PROBLEMATIC.  SOME HAD BROKEN FILAMENTS STRAIGHT OUT OF THE BOX, AND THE REST FAIL VERY VERY QUICKLY.  SOMETIMES IN LESS THAN 1 DAY, BUT THEY LAST NO LONGER THAN A WEEK.  THIS HAS BEEN OBSERVED FOR EVERY SINGLE BULB USED OUT OF A COUPLE DOZEN.  IT IS CAUSING THE NAV LIGHT SYSTEM ON OUR PLANES TO BE NOT FUNCTIONAL.

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