What happened
The pilot was operating an amateur-built, experimental aircraft when the engine suddenly seized and stopped. The mechanical failure originated from an automotive-type oil cooler that had developed a seam failure during flight. This breach resulted in the complete loss of the engine's oil supply and subsequent oil starvation.
Following the engine failure, the pilot initiated a forced landing procedure, aiming for an open field. During the approach and touchdown, the right main landing gear struck a hole in the ground. The impact caused the aircraft to lose stability and cartwheel across the surface.
The investigation
Examination of the wreckage confirmed that the engine had stopped due to oil starvation. The root cause was identified as the opening of the seam on the automotive-type oil cooler installed in the aircraft. This structural failure allowed all oil to escape during flight, leading to catastrophic engine seizure.
Findings
The sequence of events was driven by two primary factors:
- Oil cooler seam failure which caused total loss of lubrication
- Right main gear impact with a ground hole during the forced landing attempt
These combined failures resulted in the aircraft cartwheeling upon touchdown. The pilot's decision to land in a field was necessitated by the engine stoppage, but the terrain conditions contributed to the severity of the post-crash dynamics.