What happened
During a scheduled 14 CFR 135 cargo operation, the aircraft commenced its takeoff roll and successfully reached an altitude of approximately 200 feet. Shortly after liftoff, rather than executing a right-hand turn toward its planned destination, the aircraft entered a left-hand turn back toward the runway. During this maneuver, the bank angle increased to roughly 4CO degrees. The aircraft subsequently experienced a nose-down pitch and descended into snow-covered ground located approximately 200 yards north of the departure runway.
Findings
Post-accident investigations focused on the engine's condition, specifically identifying a fracture in the number six cylinder head that had partially separated from the cylinder barrel. Evidence of oil and soot was present at the separation site and within the engine cowl. A metallurgical analysis confirmed that a fatigue fracture had developed along the thread root radius between the fifth and sixth threads of the component.
Records indicated that while the operator maintained an airworthiness inspection program, the compression for the number six cylinder was measured at only 60 PSI during an inspection 121 hours prior to the event. Furthermore, the most recent engine inspection, conducted 27 hours before the accident, lacked documentation regarding engine compression levels. The crash resulted from a combination of the mechanical fatigue failure, insufficient maintenance oversight by the operator, and the pilot entering an inadvertent stall while attempting to maneuver.