NTSB Identification: CEN09LA571
14 CFR Part 91: General Aviation
Accident occurred Sunday, September 06, 2009 in Thibodaux, LA
Probable Cause Approval Date: 03/03/2010
Aircraft: MESSERSCHMITT-BOELKOW-BLOHM BO-105S, registration: N131EH
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.
While in a 3-foot hover the helicopter began an uncommanded roll to the right. The pilot unsuccessfully attempted to arrest the roll by applying full left cyclic. Moments later the right landing skid made contact with the ground, followed by the main rotor blades. The helicopter came to rest in a right-side-low, upright position and the pilot was able to exit unassisted. The purpose of the flight was to perform an operational flight check of maintenance performed to the cyclic control system. The investigation revealed that the mechanic who had performed the maintenance had inadvertently switched two cyclic control tubes, of different lengths, during reassembly. This resulted in an out-of-rig condition in the cyclic control system. No other preimpact anomalies were noted with the helicopter's flight control system.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's inability to maintain control due to the mechanic's inadvertent switching of two cyclic control tubes of different lengths during maintenance. Full narrative available
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