Lancaster, CA, USA
N632MM
SCODA AERONAUTICAL Super Petrel
While the pilot was descending toward the destination airport near the conclusion of the cross-country flight, the engine lost total power. The pilot subsequently performed a forced landing to a field, during which the right wing sustained substantial damage. During postaccident engine test runs, the engine lost power at high rpm settings. When the carburetor bowls were resealed, the engine ran with no anomalies noted. Both carburetor float bowls displayed contamination that likely affected the fuel flow to the engine; however, the extent to which the contamination contributed to the loss of engine power was not able to be determined during the investigation.
On August 25, 2019, about 1405 Pacific daylight time, a Scoda Aeronautica LTDA Super Petrel LS airplane, N632MM, was substantially damaged when it was involved in an accident near Lancaster, California. The private pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, the airplane was refueled to capacity before departing on the cross-country flight. The flight was uneventful until the pilot reduced power to begin the descent toward the destination airport, when the engine lost total power and was not responsive to throttle input. The pilot positioned the fuel selector to the opposite tank and confirmed that the fuel shutoff valve was in the ON position. The pilot performed a forced landing to an open field, during which the right wing sustained substantial damage. The airplane was equipped with a Rotax 914UL engine. The engine was equipped with dual carburetors. The engine remained relatively intact. All spark plugs were removed, with no anomalies noted. When the engine was manually rotated, no anomalies were noted through the drive train to the accessory section. The fuel pumps were examined and tested with no anomalies noted. The two carburetor float bowls and floats were removed and examined. One float bowl displayed contamination near the main jet and the other float bowl displayed contamination near one of the floats. The contamination was consistent with grease that was used on the float bowl gaskets. Fuel was added to the header tank, and about 1/2 liter of oil was added before the engine was test run several times. During the first two runs, all engine parameters were normal at a low rpm setting. However, as the throttle was advanced from 2,000 to 3,500 rpm and higher, the engine began to run rough and lose power. Before the third engine run, the original carburetor floats were removed and replaced with new floats. The subsequent engine run results were similar to the earlier runs where the engine lost power. As the floats were determined not to be an issue, the float bowls were resealed. Additional engine runs were accomplished with the new floats installed in addition to the float bowls being resealed. At low rpm settings and when the throttle was advanced to a high rpm setting, no anomalies were noted. On the final two engine 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 noted. On the second run, the original floats were also checked for leaks. Additionally, when the carburetor bowls were intentionally loosened, at low power settings no anomalies were noted. However, when the throttle was advanced to 4,090 rpm, a loss of engine lost power was observed.
The improper sealing of both carburetor bowls, which resulted in a total loss of engine power.
Source: NTSB Aviation Accident Database
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