NTSB Identification: CEN13LA115
14 CFR Part 91: General Aviation
Accident occurred Sunday, December 23, 2012 in Corcoran, MN
Probable Cause Approval Date: 11/13/2014
Aircraft: ROBINSON HELICOPTER R22 BETA, registration: N27AT
Injuries: 1 Minor.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
Before landing, the pilot hovered the helicopter about 10 feet above the ground to see if tarps covering the north half of the concrete helipad would move, and he then decided to continue the landing. The helicopter approached from the north, which placed the tail rotor over the tarps. The area south of the helipad was free of obstructions. While the pilot was shutting down the helicopter after landing, the helicopter made an uncommanded counterclockwise rotation of about 40 degrees. The pilot applied corrective pedal input with no response. The helicopter then rotated about three full revolutions before the tail boom and main rotors struck a nearby parked trailer, and a fire ensued. Postaccident examination of the helicopter did not reveal any preimpact anomalies; however, the examination was limited due to extensive impact and postimpact fire damage. Examination of the accident site revealed several cuts in the tarp in the area where the tail boom was positioned during landing. Although the pilot reported that the tarp did not impact the tail rotor, the evidence suggests that the tarp was lifted into the tail rotor during the shutdown, which likely caused damage to the tail rotor blades and resulted in a loss of tail rotor authority and the subsequent uncommanded rotation. Further, because the area south of the pad was free of obstructions and the reported wind was variable at 2 knots, the pilot could have landed the helicopter facing north, which would have placed the tail rotor over the unobstructed ground south of the helipad.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot’s improper decision to land the helicopter in a position that placed the tail rotor near tarps, which resulted in the tarps being lifted into the tail rotor, subsequent tail rotor damage, a loss of tail rotor authority, and an uncommanded tail rotor rotation.
Full narrative available
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