What happened
A maintenance test flight was underway under conditions involving wind gusts up to 27 knots. Prior to departure, the pilot completed an NTS check on both engines, which revealed no issues. During the flight, the pilot conducted an additional NTS check on the left engine, during which two attempts to restart the engine failed. Although the propeller moved from the feathered position to a rotating state during these attempts, there was no ignition or fuel flow detected.
The crew returned to the airport to land. While on short final for runway 29, with winds originating from 250 degrees at 20 knots, an observer noted the aircraft pitch upward and then downward, accompanied by the sound of power being applied to the right engine. Following this, the aircraft rolled to the left and pitched nose down, striking the ground. The impact left the aircraft type (not specified, but engine/propeller details provided) in a nearly inverted position with a wing section separated. There were no fatalities reported in the provided text, though the impact was severe.
Findings
Post-accident inspections of the left engine and its associated accessories showed no signs of malfunction or failure prior to the impact. However, investigators discovered that the left engine fuel shutoff valve was in the closed position, and no fuel was present downstream of that valve. Both the left and right engines had recently undergone 'hot section' maintenance and were installed prior to the flight. Maintenance personnel had successfully started both engines the previous day without any noted discrepancies.