What happened
While returning from a job site involving the transport of hazardous blasting materials, a flight carrying the pilot and five passengers encountered a critical mechanical failure. The aircraft type was climbing at an altitude of 8,500 feet when the engine suffered a catastrophic failure. Following the declaration of an emergency, the pilot executed a forced landing into a field.
During the landing sequence, the right wing of the aircraft made contact with a tree, causing it to separate from the fuselage. Although all six occupants managed to exit the aircraft without any injuries, the plane was subsequently overtaken by fire. The flames were intense enough to consume the majority of the airframe.
Findings
Investigation of the turbine engine, which had logged approximately 7,620 total hours and 65 hours since its last overhaul, revealed significant internal damage. Evidence of impact was found within the engine exhaust duct, which contained fragments of a broken power turbine blade.
Further inspection of the engine components identified damage to the compressor turbine and power turbine, consistent with a distressed 1st stage sun gear. While the output splines of the sun gear teeth showed deterioration, the specific cause of this wear could not be determined. Notably, the sun gear used in the accident engine had been previously removed from a different engine seven years prior due to spalled gear teeth, though its exact condition at the time of installation in the accident aircraft remained undetermined.