What happened
The flight was the first operation following the completion of an annual inspection. Prior to the initial takeoff, the pilot performed taxi tests and noted no discrepancies. The engine started easily and operated smoothly at lower RPM settings. An engine run-up, including a magneto check, was completed without any anomalies.
During the takeoff roll, the pilot observed that the engine failed to produce full power, noting that the RPM did not exceed 1,600. The pilot elected to continue the takeoff and subsequently attempted to turn the aircraft back toward the runway to land. While performing a crosswind to downwind turn, the left wing stalled. This resulted in the airplane pitching down and falling approximately 50 feet to the ground. There were no injuries reported.
The investigation
An inspection of the engine revealed weak compression in two cylinders. Further examination identified leaks originating from both the intake and exhaust valves within those two cylinders. No other discrepancies were found during the mechanical examination.