Aerotek PITTS S 2A accident near Sheboygan Falls, Wisconsin, May 26, 2017

The NTSB's narrative final · quoted from the NTSB record

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.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.