What happened
The pilot reported that shortly after takeoff, the engine began running roughly. Air traffic control cleared the pilot to land on any available runway. The pilot selected runway 10 for landing. As the aircraft approached the threshold, one notch of flaps was extended. The aircraft continued to float along the runway and touched down with approximately one-third of the runway remaining. Brakes were applied immediately upon touchdown; however, the aircraft failed to stop within the paved surface. It continued off the end of the runway, where it contacted a ditch and nosed over.
The investigation
A post-accident examination of the aircraft revealed that the number four cylinder exhaust valve was stuck in place. This mechanical failure prevented proper engine operation, leading to the rough running condition reported by the pilot shortly after departure.
Findings
The primary factor contributing to the accident was the stuck #4 cylinder exhaust valve, which caused the engine to run roughly. The aircraft's inability to stop on the remaining runway length resulted in a ground contact with a ditch and subsequent nose-over. The runway excursion was a direct consequence of the mechanical failure combined with the landing performance on the available pavement.
Safety message
Regular maintenance checks are critical to identifying potential valve or exhaust system issues before they lead to in-flight engine roughness or power loss. Pilots should be aware that engine irregularities shortly after takeoff may limit options for safe recovery, making early recognition and appropriate emergency procedures essential.