Accident Sequence
On the day of the occurrence, witnesses first observed the aircraft on final approach for landing. The engine(s) were heard making a backfiring sound. While the aircraft was on short final, another aircraft pulled onto the runway and began its takeoff roll. The accident aircraft was then observed to initiate a go-around. During the go-around, it did not appear to be gaining altitude and was at what witnesses thought was a slow airspeed. About mid-field, the aircraft made an approximate 45-degree turn from runway heading. Within one-quarter mile from the runway, the aircraft lost altitude. According to witnesses, the aircraft was about 80 feet above ground level when it stalled, rolled inverted (left wing down), and collided with the flat open terrain in a nose-low attitude.
Post-Crash Fire and Wreckage
A post-crash fire subsequently consumed the wreckage. The fire and impact destroyed the aircraft, leaving little structural evidence beyond the powerplants.
Engine Findings
During the post-crash inspection of the engines, both engines showed signs of operating at a lean mixture setting. The left engine pistons and spark plugs displayed a more serious lean condition than those on the right side. The left engine also exhibited early signs of detonation on the piston heads. No other mechanical failure or malfunction was noted in either the engines or the airframe.
Probable Cause
The official probable cause statement cites the pilot's failure to maintain airspeed while maneuvering, an inadvertent stall, the pilot's failure to follow engine operation procedures, and engine detonation as factors.