Accident Details
On August 25, 2019, at approximately 1405 Pacific daylight time, a Scoda Aeronautica LTDA Super Petrel LS airplane (registration N632MM) was substantially damaged in an accident near Lancaster, California. The private pilot and one passenger were not injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
According to the pilot, the airplane was refueled to capacity before departure on a cross-country flight. The flight proceeded normally until the pilot reduced power to begin a descent toward the destination airport. At that point, the engine lost all power and did not respond to throttle inputs. The pilot switched the fuel selector to the opposite tank and verified that the fuel shutoff valve was in the ON position. A forced landing was performed in an open field. During the landing, the right wing sustained substantial damage.
Engine Examination and Testing
The airplane was equipped with a Rotax 914UL engine with dual carburetors. Post-accident examination found the engine relatively intact. All spark plugs were removed and showed no anomalies. Manual rotation of the engine revealed no issues through the drive train to the accessory section. Fuel pumps were tested and found to be normal.
When the two carburetor float bowls and floats were removed, contamination was observed near the main jet in one bowl and near one of the floats in the other. The contaminant was consistent with grease used on the float bowl gaskets.
Fuel was added to the header tank, and approximately half a liter of oil was added before the engine was test run multiple times. During the first two runs, engine parameters were normal at low rpm. However, when the throttle was advanced from 2,000 to 3,500 rpm and higher, the engine ran rough and lost power.
Before a third engine run, the original carburetor floats were replaced with new floats. The subsequent run produced similar power loss as before. The floats were ruled out as the cause. The float bowls were then resealed. Additional runs with new floats and resealed bowls showed no anomalies at low or high rpm settings.
In the final two runs, the original floats were reinstalled and the float bowls resealed. During the first run, the throttle was advanced from 2,000 to 4,219 rpm with no anomalies. On the second run, the original floats were checked for leaks. When the carburetor bowls were intentionally loosened, no anomalies were observed at low power. However, when the throttle was advanced to 4,090 rpm, a loss of engine power occurred.
Probable Cause
The investigation did not state a probable cause.