QUINCY, CA, USA
N9218P
PIPER PA-24-260
THE PLT WAS UNABLE TO START THE ENG & OBTAINED THE SERVICE OF A MECHANIC. THE MECHANIC DECIDED THAT THE PROBLEM WAS IN THE IGNITION SWITCH & DISCONNECTED THE P-LEADS WITH THE BELIEF THAT THIS WOULD MAKE THE MAGS CONTINUALLY 'HOT.' HOWEVER, WITH THE P-LEADS DISCONNECTED, THE MAGS SHOULD HAVE BEEN CONTINUALLY GROUNDED BY LEAF SPRING CONNECTORS. NEVER-THE-LESS, THE ENG STARTED WITH THE P-LEADS DISCONNECTED. AFTER TAKEOFF, WITH NO MAG CHECK, THE ENG BEGAN TO VIBRATE & MISFIRE & THE PLT TRIED TO RETURN TO THE ARPT. HOWEVER, THE ENG LOST ALL POWER & THE GEAR COLLAPSED DURING A FORCED LANDING, SHORT OF THE RWY. AN EXAM REVEALED THAT WITH THE P-LEADS DISCONNECTED, THE RGT LEAF SPRING CONNECTOR EFFECTIVELY GROUNDED THE RGT MAG, BUT THE LEFT MAG REMAIND UNGROUNDED FOR A TIME. THERE WAS EVIDENCE OF ARCING BETWEEN THE LEFT LEAF SPRING CONNECTOR & THE MAGNETO CASE. ALSO, THE SPARK VIBRATOR WAS FOUND TO BE WEAK. NO OTHER PREIMPACT MECHANICAL PROBLEM WAS FOUND.
Source: NTSB Aviation Accident Database
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