# SDR 20000720SH026

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 5, 2000
- Submitted: July 20, 2000
- Operation: General aviation
- Aircraft: N4573V
- Make and model: Cessna 414A
- Registry model: [Cessna 414A](https://openairdocs.org/model/cessna-414a) (OpenAirDocs)
- Aircraft serial: 414A0300
- System (JASC): [2400 · Electrical Power System](https://openairdocs.org/jasc/2400)
- Part: Circuit Breaker
- Part number: W31X104450
- Condition: Burned Out
- Location: Avionics System
- Stage of operation: IN
- How discovered: C
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/20000720SH026

## Discrepancy

AFTER TAKEOFF,THERE WAS A SMELL OF SMOKE IN THE COCKPIT.  THE SMELL WAS COMING FROM THE AREA OF AVIONICS MASTER BREAKER/SWITCH.  DISCOVERED THE POTTER & BRUMFIELD BREAKER/SWITCH, PN W31-X1000-50, HAD OVERHEATED AND THE BREAKER POINTS HAD WELDED SHUT.  THIS RENDERED THE SWITCH PORTION OF THE BREAKER/SWITCH INOPERATIVE.  THIS BREAKER/SWITCH HAD FAILED BEFORE ON THER AIRCRAFT, BUT NEVER IN FLIGHT. THE FAILURES USUALLY OCCURRED ON THE GROUND DURING GROUND OPERATION OR PRE-FLIGHT.  THE AVIONICS SYSTEM IS PROTECTED BY A SECOND CIRCUIT BREAKER, PN 7815-15-50, LOCATED IN THE LEFT WING ROOT FWD OF THE BATTERY BOX WHICH WILL TRIP IF THERE IS AN OVERLOAD.  (X)

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