Aerotek PITTS S 2A N67PN accident near Sheboygan Falls, Wisconsin

Probable cause

The pilot's failure to maintain airplane control following a partial loss of engine power during a low-level aerobatic maneuver; the reason for the loss of engine power could not be determined during postaccident examination of the engine. Contributing to the accident was the pilot's exceedance of the airplane's published maximum gross weight and center of gravity limits for the acrobatic category.

NTSB analysis

The airline transport pilot and a private pilot-rated passenger departed in an aerobatic airplane to perform a fly-by over a local raceway. About 10 minutes after the fly-by, one witness saw the airplane flying level when its engine stopped producing sound. The airplane continued level flight for several seconds before it suddenly entered a nose-down, descending spiral and impacted the ground. However, two other witnesses saw the airplane conduct a vertical climb before entering what they described as a "corkscrew" and a "fast spin." Both of these witnesses described engine sound anomalies and that they thought the pilot was trying to restart the engine.

The airplane came to rest inverted on plowed terrain. Signatures on the propeller were consistent with the engine not producing significant power at the time of impact; however, examination of the wreckage did not reveal any preimpact anomalies that would have precluded operation of the airplane and engine.

Weight and balance calculations were produced using occupant weights at various fuel loads. Even at minimum fuel, the airplane was operating above its maximum gross weight of 1,500 lbs for approved flight in the acrobatic category at the time of the accident. Additionally, the airplane's calculated center of gravity was outside the envelope for the acrobatic category. It is likely the airplane's gross weight exceedance and operation outside the weight and balance envelope for aerobatic flight contributed to the pilot's difficulty in adequately controlling the airplane.

The investigation could not determine which occupant was manipulating the controls at the time of the accident. Regardless, the pilot was responsible for maintaining flight control.

Text from the NTSB. Open the NTSB docket for CEN17FA197 for the full record.