What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) During the initial engine starting procedure (cranking engine with starter energizer) an explosion occurred. The explosion caused substantial damage to the a/c from the cockpit all the way through the fuselage and up through the vertical stabilizer. Post-explosion investigation revealed the following: 1. The main fuel tank for the airplane is located aft of the rear seat backs, and a bulkhead separates the seat backs from the tank 2) at leastr one fuel line fitting under this tank was wet to the touch with a liquid that had the aroma of aviation gas 30 the airplane's battery is located under the right rear seat. The negative battery terminal connects to the airframe via a flat, braided ground strap; the connection at the airframe was corrodes 4) the battery is covered with a clear plexi-glass cover, but the compartment which this crates is not sealed. 5) post-explosion investigation found the battery ground strap to be completely separated at its lower end. The ends of several of the wire braids had globules of molten material, and they were charred and discolored.
As the FAA filed it
(-23) DURING THE INITIAL ENGINE STARTING PROCEDURE (CRANKING ENGINE WITH STARTER ENERGIZER) AN EXPLOSION OCCURRED. THE EXPLOSION CAUSED SUBSTANTIAL DAMAGE TO THE A/C FROM THE COCKPIT ALL THE WAY THROUGH THE FUSELAGE AND UP THROUGH THE VERTICAL STABILIZER. POST-EXPLOSION INVESTIGATION REVEALED THE FOLLOWING: 1. THE MAIN FUEL TANK FOR THE AIRPLANE IS LOCATED AFT OF THE REAR SEAT BACKS, AND A BULKHEAD SEPARATES THE SEAT BACKS FROM THE TANK 2) AT LEASTR ONE FUEL LINE FITTING UNDER THIS TANK WAS WET TO THE TOUCH WITH A LIQUID THAT HAD THE AROMA OF AVIATION GAS 30 THE AIRPLANE'S BATTERY IS LOCATED UNDER THE RIGHT REAR SEAT. THE NEGATIVE BATTERY TERMINAL CONNECTS TO THE AIRFRAME VIA A FLAT, BRAIDED GROUND STRAP; THE CONNECTION AT THE AIRFRAME WAS CORRODES 4) THE BATTERY IS COVERED WITH A CLEAR PLEXI-GLASS COVER, BUT THE COMPARTMENT WHICH THIS CRATES IS NOT SEALED. 5) POST-EXPLOSION INVESTIGATION FOUND THE BATTERY GROUND STRAP TO BE COMPLETELY SEPARATED AT ITS LOWER END. THE ENDS OF SEVERAL OF THE WIRE BRAIDS HAD GLOBULES OF MOLTEN MATERIAL, AND THEY WERE CHARRED AND DISCOLORED.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.