CHI06LA273

The failure of a welded joint at a cyclic control cable bracket located on the main rotor mast which made control of the helicopter impossible for the pilot.

The amateur built helicopter impacted the ground during a test flight following the failure of a welded joint at a cyclic control cable bracket resulting in a loss of control authority. A post impact fire ensued destroying the helicopter. The pilot reported he was in a low hover when the tail came up and the helicopter tilted. One of the skids subsequently caught the ground causing the helicopter to roll over. Examination of the helicopter revealed that a welded joint failed at a cyclic control cable bracket on the main rotor mast. Failure of the welded bracket caused the loss of input control authority from the cyclic control to the main rotor.

On September 28, 2006, about 1820 central daylight time, an amateur built Daub Pawnee Chief helicopter, N565CH, piloted by a private pilot, was destroyed when it impacted the ground following a loss of flight control authority while hovering in ground effect at McCook Regional Airport (MCK), McCook, Nebraska. A post impact fire ensued. The test flight was being conducted under 14 CFR Part 91 without a flight plan. Visual meteorological conditions prevailed at the time of the accident. The pilot and passenger sustained minor injuries. The local flight originated from MCK about 1800. The pilot was conducting test flights in a low hover, three to four feet above the ground. The pilot stated that while hovering, the tail came up and one of the skids caught the ground. The helicopter subsequently rolled over. He noted that the ground consisted of tall grass and soft dirt. Post accident inspection of the helicopter revealed that a cyclic control cable bracket had separated from the main rotor mast at a welded joint. The bracket secured the end of the control cable shroud. The cable itself provided control authority from the cyclic to the main rotor.