NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The 2,919-hour airline transport rated pilot stated that the airplane was climbing through an altitude of 5,500 feet mean sea level (msl) when he heard a "pop" and started to smell something "funny," but there was no visible smoke. He elected to go to the nearest airport and land, and noticed that his push-to-talk button was no longer operative. The pilot set code 7700 in the transponder and began a descent. During the descent, the cockpit began to fill with an "acrid black" smoke, and he saw flames through an opening in the instrument panel. The pilot attempted to suppress the fire with a hand-held fire extinguisher; however, he was unsuccessful. The pilot elected to execute an emergency landing in a field, collided with a barbed wire fence, and the airplane was then consumed by fire. Examination of the airplane's electrical system revealed that the main battery cable that ran between the main power relay and the main power bus was severed approximately two inches from the main bus. There was beading and localized melting on both ends. Under magnification, the damaged areas had an eroded appearance and there was some evidence of pitting. This type of damage is indicative of an electrical arcing event, which most likely ignited the insulation surrounding the main power wiring assembly and spread to other combustible items in the area. The initiating event for the arc could not be determined.