Primary finding
Probable cause
the failure of the tail rotor drive belt for undetermined reasons. A contributing factor was the lack of suitable terrain for the forced landing.
Investigator assessment
Analysis narrative
Approximately 15 minutes into the flight, the tail rotor failed, and the helicopter entered an uncommanded turn to the left. The pilot initiated an autorotation to an opening in a wooded area. The pilot flared the helicopter over the trees, and the helicopter settled into the trees. As the pilot increased the collective, the helicopter rolled to the left and came to rest inverted in the trees. Examination of the helicopter by the pilot and a mechanic revealed that the tail rotor drive system uses three belts interconnected via pulleys at various points in the tail boom, to drive the tail rotor. The intermediate tail rotor drive belt was shredded and destroyed. The forward and aft tail rotor drive belts were intact and undamaged. At the time of the accident, the tail rotor drive belts had accumulated approximately 80 hours. The tail rotor drive belts had a life limit of 250 hours. The reason for the failure of the tail rotor drive belt could not be determined.
Source record
Factual narrative
On January 3, 2007, at 1505 central standard time, a Marino Exec 162F-1995 single-engine homebuilt helicopter, N113JD, sustained substantial damage when it impacted trees and terrain during a forced landing following a loss of control near Baldwin City, Kansas. The airline transport pilot sustained serious injuries and the passenger sustained minor injuries. The helicopter was registered to and operated by the pilot. Visual meteorological conditions prevailed, and a flight plan was not filed for the Title 14 Code of Federal Regulations Part 91 personal flight. The local flight departed Paola, Kansas, approximately 1500, and was en route to Lawrence, Kansas. According to the pilot, approximately 15 minutes into the flight, the "tail rotor failed," and the helicopter entered an uncommanded turn to the left. The pilot initiated an autorotation to an opening in a wooded area. The pilot flared the helicopter over the trees, and the helicopter settled into the trees. As the pilot increased the collective, the helicopter rolled to the left and came to rest inverted in the trees. The fuselage and tail boom sustained substantial damage and the main rotor blades were destroyed. Examination of the helicopter by the pilot and a mechanic revealed that the tail rotor drive system uses three belts interconnected via pulleys at various points in the tail boom, to drive the tail rotor. The intermediate tail rotor drive belt was shredded and destroyed. The forward and aft tail rotor drive belts were intact and undamaged. At the time of the accident, the tail rotor drive belts had accumulated approximately 80 hours. The tail rotor drive belts had a life limit of 250 hours. The reason for the failure of the tail rotor drive belt could not be determined.