# SDR M7K2008F00130

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 14, 2008
- Submitted: August 5, 2008
- Operation: Air carrier
- Aircraft: [N816MH](https://openairdocs.org/aircraft/N816MH), registered now
- Make and model: Urocop EC 130 B4
- Registry model: [Urocop EC 130 B4](https://openairdocs.org/model/eurocopter-ec-130-b4) (OpenAirDocs)
- Aircraft serial: 4038
- Engine: Tmeca ARRIEL2B1
- System (JASC): [3397 · Light System Wiring](https://openairdocs.org/jasc/3397)
- Part: Wire
- Condition: Shorted
- Location: Tail Light
- Part time: 1,976 hours
- Stage of operation: IN
- How discovered: C
- Nature of condition: L
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/M7K2008F00130

## Discrepancy

DURING PREFLIGHT INSP POSITION LIGHTS FAILED TO ILLUMINATE.  INVESTIGATION REVEALED CIRCUIT BREAKER HAD POPPED.  A SHORT WAS LOCATED IN THE TAIL POSITION LIGHT WIRING AND A REPAIR EMBODIED.  RESETTING THE BREAKER FOR A GROUND TEST REVEALED NO FUNCTION FOLLOWING WIRING REPAIR.  FURTHER INVESTIGATION REVEALED THE PCB RIBBON FOR THE POSITION LIGHTS SWITCH HAD BURNED UP ON BACK OF THE SWITCH BOARD.  THIS IS A COMMON FAULT FOR THIS PART AS THE CIRCUIT RIBBON FOR THIS PART IS NOT LARGE ENOUGH TO CARRY THE CURRENT THAT THIS CIRCUIT USES WHEN A SHORT OCCURS AND THE BOARD RIBBON MELTS RAPIDLY MUCH LIKE A FUSE BEFORE THE BREAKER WILL POP WHEN A WIRING SHORT DOES OCCUR.  SUGGEST THAT A REDESIGN OF THIS CIRCUIT SO THE PANEL IS PROTECTED FROM SHORT DAMAGE IS REQUIRED.  THIS FAILURE HAS GENERATED O SMOKE, FUMES TO ANYONE’S KNOWLEDGE AND DOES NOT APPEAR TO BE A FIRE HAZARD.  (K)

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