Incident Description
The accident occurred during a routine biennial flight review. The pilot was flying the approach to the airport when a distinct snapping sound was audible from the aircraft's structure. Immediately afterward, the elevator controls became inoperative. The pilot, maintaining composure, guided the airplane to a landing on the runway. However, upon touchdown, the tail of the aircraft remained elevated, preventing a normal three-point landing. When the pilot engaged the brakes, the aircraft nosed over and came to rest upside down.
Post-Incident Examination
Investigators conducted a thorough examination of the aircraft's control system. They discovered that the metal arm connecting the elevator control surface to the bell crank had broken completely. The fracture surfaces indicated that the break had been preceded by extensive corrosion. Further analysis revealed that moisture had penetrated the arm, leading to rust that had gradually eroded the metal from the interior outward. This internal corrosion had weakened the arm until it was unable to withstand the loads experienced during flight, resulting in the sudden failure.
Investigation Conclusion
The investigation determined that the broken elevator arm was the direct cause of the loss of control. The presence of water and the resulting corrosion were identified as the underlying conditions that led to the arm's failure. No other contributing factors were noted in the official report.