What happened
During a climb from takeoff at approximately 300 feet above the ground, the pilot reported that the engine underwent a gradual loss of power, describing the sensation as if the power were being slowly reduced. An observer on the ground, who is also a pilot, noted that the aircraft initially assumed an attitude similar to a landing flare before pitching forward and descending vertically toward the ground.
The pilot indicated that the loss of engine power may have led to an unintentional stall. The aircraft crashed into a small, unnamed lake, where it flipped onto its back and remained submerged for 48 hours. There were no injuries reported.
The investigation
Investigators performed both external and internal examinations of the powerplant assembly and the fuel system hardware. This examination did not reveal any failures or anomalies that would suggest an inoperative condition. Additionally, the fuel source used to replenish the aircraft was found to be unremarkable.