On 13 Jan 2008, a Bell 206 B2 operated by Robert L. Miars was involved in an aviation accident near La Verna, CA. No fatalities were reported. Investigators recorded the probable cause as: The test equipment became entangled at the left cyclic attach point and prevented full cyclic control. This summary draws on records from NTSB; 12 related events involving the same aircraft type or operator are linked below.
A helicopter conducting a maintenance test flight for rotor track and balance lost control during a hover, colliding with terrain and sustaining substantial fuselage damage. The left cyclic control was removed without a protective cover, and test equipment became entangled at the attach point.
Accident Overview
A commercial pilot and a mechanic were performing a maintenance test flight to conduct a dynamic track and balance of the main rotor system when the accident occurred. According to a written statement from the pilot, the helicopter was in a three-foot hover and moving forward when control was lost. The helicopter subsequently collided with terrain, resulting in substantial damage to the fuselage.
Pilot Statement
The pilot reported that the left cyclic control had been removed prior to the flight, but the protective cover was not installed. During the accident flight, the test equipment used for track and balance became entangled at the left cyclic attach point, preventing full cyclic control.
Damage
The collision with terrain caused substantial damage to the fuselage of the helicopter.
Probable cause
The test equipment became entangled at the left cyclic attach point and prevented full cyclic control.