What happened
On August 4, 2012, a Piaggio P149D, registration D-EGIT, departed from Hoogeveen Airport for a local flight. Approximately 15 minutes into the flight, the engine began to run roughly and eventually failed completely. During the descent, smoke from the engine entered the cockpit, creating a high-stress environment for the two crew members.
In an attempt to land as quickly as possible due to fears of an in-flight fire, the crew executed an emergency descent. However, the aircraft's high speed caused the crew to overshoot the intended emergency landing field. While attempting to avoid a line of trees, the aircraft struck the trees, which tore away a portion of the left wing. The aircraft became uncontrollable and finally came to rest after striking a shed adjacent to a residential house. The pilot sustained heavy injuries, while the second crew member suffered light injuries. The aircraft was destroyed.
The investigation
Investigators examined the engine, a Lycoming GO-480-B1A6, which had undergone a full overhaul only four flying hours prior to the accident. Analysis of the engine components, supported by findings from the NTSB, revealed that the engine crankcase had been punctured. Specifically, the connecting rod for cylinder number five had broken at the upper eye.
Because the connecting rod was no longer attached to the piston, the piston was able to move upward into an abnormal position, causing it to strike the intake and exhaust valves. This mechanical failure resulted in significant internal damage and the eventual seizure of the engine. The investigation also looked into the flight dynamics during the emergency, noting that the high airspeed prevented the crew from manually deploying the flaps.