Amateur-built SONEX N634SX accident near Naples, Florida

Probable cause

The pilot’s failure to maintain airspeed during a forced landing, which resulted in an aerodynamic stall. Contributing to the accident was a partial loss of the noncertificated engine’s power for reasons that could not be determined because examination of the engine did not reveal any mechanical malfunctions or failures that would have precluded normal operation.

NTSB analysis

About 5 minutes after takeoff and at a cruise altitude of 2,000 feet above ground level, the engine lost oil pressure and partial power. The pilot was unable to maintain the airplane's altitude and flew toward a golf course to conduct a forced landing. During short final approach, he turned the airplane left to better align it with a fairway, but the airplane stalled and impacted a canal. The airplane was equipped with a noncertificated, modified automobile engine. Examination of the wreckage did not reveal any cracks in the engine case, oil residue in the engine compartment, or any abnormalities that would have accounted for the sudden loss of oil pressure and partial engine power.

Text from the NTSB. Open the NTSB docket for ERA13LA254 for the full record.