Mechanical Error Cited in Huey Crash Outside Minot

Mechanical error caused a UH-1N Huey helicopter to make an emergency landing outside Minot AFB, N.D., last February, according to an accident investigation board report summary released last week. The report found the Feb. 25 mishap was caused by a loss of tail rotor thrust, which was followed by a driveshaft coupling failure. “Approximately an hour into the flight, the crew from the 54th Helicopter Squadron heard a loud noise coming from the rear of the aircraft and felt an accompanying vibration,” states the summary, released Dec. 20. “The pilot chose to make a precautionary landing in a snow-covered field.” After the tail rotor lost thrust about 100 feet off the ground, the pilot continued to autorotate—a procedure where the main rotor system uses air moving through the rotor instead of engine power to keep turning. When the helicopter was about 30 feet off the ground, the pilot applied control inputs to level the aircraft and cushion the landing, states the summary. However, the right rear skid hit the ground before the left skid, causing the main rotor blades to strike the ground when the aircraft rolled to the left and landed on its side. Three aircrew members were injured, but there were no civilian injuries or damage to civilian property, states the summary. The helicopter was considered a total loss with more than $2.3 million in damages.