Colorado Aviation Accidents & Incidents

On May 7, 2013, about 1149 mountain daylight time, a Bell model 206L-1 helicopter, N20Z, sustained substantial damage when it impacted the ground near La Junta, Colorado, following an in-flight loss of tail rotor control. The pilot and two passengers were not injured. The helicopter's tail boom was separated and it sustained additional damage to the fuselage and main rotor system. The aircraft was registered to Helicopters Inc. and operated by Corporate Aircraft Services under the provisions of 14 Code of Federal Regulations Part 91 as an aerial observation flight. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The local flight originated from the La Junta Municipal Airport (LHX), La Junta, Colorado at 1135.The pilot reported that the purpose of the flight was videotaping of a pipeline corridor. He stated that the flight was conducted maintaining altitude between 50 and 100 feet above ground level at 45 to 55 kts ground speed. At no point was a hover commanded, and the flight plan called for forward flight at all times. The helicopter completed one flight and then landed at the LHX and re-fueled. In order to maintain weight and balance, 50 gallons of fuel was added to the helicopter. The helicopter departed LHX to continue the videotaping work until the next re-fueling point. The flight path was generally southwest over mainly flat rural areas with low vegetation. About 1200, the helicopter made an uncommanded yaw to the left for about 1-2 seconds and then returned to straight flight. The pilot reported that a passenger noticed the engine torque spike from 55-percent to about 115-percent. He stated that there was a distinct change in engine pitch as well. Following the uncommanded left yaw, the helicopter returned to straight flight for about 1-2 seconds and then began an uncommanded yaw to the right. The right yaw continued until the helicopter struck the ground. The pilot stated that when the right yaw began he treated it as a loss of tail rotor effectiveness (LTE) and lowered the collective, reduced throttle, and kept the helicopter as level as possible while providing cushion for the landing with collective. After the airplane touched down, it rolled onto its left side.

The wreckage was moved to a maintenance facility where a postaccident examination of the helicopter was conducted. The fuselage of the helicopter was predominately intact with crushing damage from impact evident. The engine was intact and the rotating components could be spun freely with no evidence of an internal failure. The main rotor gearbox remained attached to its supporting structure atop the fuselage. The main rotor mast was bent where it exited the gearbox. Due to the bending of the main rotor mast, the swashplate control connections were broken. The breaks exhibited signatures consistent with postimpact overload failure. The remainder of the control system was examined and no preimpact defects were found. There w