The pilot reported that he planned to take off and circle the experimental, amateur-built airplane above the runway at the airport in Homer, Louisiana, to check engine operation. Just after takeoff, the engine began sputtering.
He made a left 180° turn to return to the runway and, during the turn, the engine experienced a total loss of power. The pilot noted the Angel Hawk II stalled when he was in the turn and he did not have enough time to recover before hitting the ground. The pilot was seriously injured in the crash.
The airplane had accumulated about 47 hours of run time and was in the initial flight test stage when the accident occurred.
The pilot reported that he had been having trouble with increased cylinder head temperatures on the converted automotive engine. The engine had experienced a total loss of power during a previous flight, but the pilot was able to land the airplane without incident.
Following that event, he replaced some ignition system components and adjusted the valves. He was then able to start the engine and reported that it “ran fine” during subsequent test runs.
Post-accident examination of the airplane revealed that the fuel mixture was not adjustable in the cockpit. Examination of the engine revealed that there was melted plastic material inside the distributor rotor and the distributor drive shaft. The condition of the spark plugs was consistent with an overly lean fuel mixture and/or high temperature operation.
It is likely that the melted distributor rotor was the result of the engine’s high operating temperatures. The degradation of the distributor and its drive shaft would have resulted in a shift in ignition timing and a subsequent loss of engine power.
Probable cause: A total loss of engine power due to the engine’s unresolved high operating temperatures, which resulted in failure of the distributor rotor and drive shaft, and the pilot’s failure to maintain airspeed during the subsequent forced landing, which resulted in an aerodynamic stall and loss of control.
NTSB Identification: CEN17LA228
This June 2017 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.