Accident Summary
On July 20, 2018, about 1215 central daylight time, a Bell 206B helicopter, registration N325CT, sustained substantial damage during an accident near Todd Mission, Texas. The private pilot and one passenger sustained minor injuries, while two passengers were uninjured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Flight Sequence
After local flying and refueling, the pilot landed on a grass field to allow passengers to switch seats. During the seat-switching process, the pilot reduced the throttle to flight idle. Once passengers were seated and secured—with one passenger in the front left seat and two in the cabin—the pilot increased throttle to 100% and lifted off. Review of video footage revealed the helicopter began rotating right during takeoff. The pilot reported that at about 10 feet above ground level and 5 knots forward airspeed on a heading of 270°, the helicopter completed four 360° right rotations. Despite full left pedal application, the helicopter did not respond. The pilot noted a torque gauge jump and heard a whining noise from the engine. Before impact, the pilot reduced throttle to flight idle. The left skid struck the ground, the helicopter rolled left, and came to rest on its left side. The pilot executed an emergency shutdown, and all occupants evacuated without further incident.
Postaccident Examination
Substantial damage occurred to the main rotor system, fuselage, tailboom, and tail rotor system. A postaccident examination of the airframe and engine revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation.
Foot Interference Testing
The helicopter's flight controls—cyclic, collective, and both tail rotor pedals—were installed in the left side. The pilot reported briefing all passengers not to touch any flight controls. When asked if he had placed his feet on top of the tail rotor pedals as a footrest, the front left passenger stated "that or on the floor" and was not sure. Postaccident testing was conducted in a Bell 206B flight training device. With wind conditions replicated, the NTSB investigator-in-charge (IIC) rested his feet on top of the tail rotor pedals for two iterations: one with no force and one with medium force. In both, the chief training pilot (CTP) attempting takeoff found the helicopter immediately rotated right and was difficult to control directionally. In a third iteration, the IIC placed the tips of his feet on the floorboards against the tail rotor pedals; the same right rotation and loss of directional control occurred.
Flight Manual Guidance
A review of the Bell 206B rotorcraft flight manual found no guidance regarding the carrying of passengers in the cockpit and the interference of flight controls. The Federal Aviation Administration Helicopter Flying Handbook (FAA-H-8083-21B) discusses operations when carrying passengers in the cockpit and recommends, if possible, removing front passenger flight controls and securing personal items.