Accident Details
On June 23, 2017, at about 1315 eastern daylight time, a Hughes 369E helicopter, registration N765KV, operated by Haverfield Aviation Inc, was substantially damaged during a hard landing near Dennis, West Virginia. The commercial pilot was not injured. The flight was conducted as an external load operation under Title 14 Code of Federal Regulations Part 133. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight.
The pilot reported that he returned to the landing zone with a conductor attached to a long line. While hovering at 100 feet above the landing zone, a ground crew member was tasked with disconnecting the conductor. The helicopter began to settle, and the pilot raised the collective control. However, the helicopter continued to descend as a warning horn sounded and the engine noise ceased. The pilot then entered an autorotation, and during the landing, a main rotor blade contacted the tailboom, resulting in a tailboom separation.
The pilot added that prior to the hover, he was pulling the conductor with the helicopter in an aft or left attitude. He estimated that the loss of engine power occurred 45 seconds to 1 minute after transitioning from the pull to a hover.
Examination Findings
A Federal Aviation Administration (FAA) inspector witnessed a subsequent wreckage examination, which included a successful test-run of the engine. No preimpact mechanical malfunctions were noted. The low fuel light illuminated when the helicopter was positioned nose-up with the remaining fuel on board. The inspector reported that approximately 7 gallons of fuel remained in each of the two fuel tanks at the time of the loss of engine power. The two tanks were connected by an interconnect passage, and each tank had an internal baffle. The fuel pickup was located in the right front portion of the left fuel tank.
The FAA inspector further stated that during the accident flight, the conductor was not completely off the ground and was being dragged over terrain. To compensate for the dragging resistance, the pilot had the helicopter in an aft or left attitude, with a higher nose-up attitude than normal flight.
Fuel Management
The operator's risk assessment form required that the helicopter be topped off (64 gallons) with fuel prior to side pull operations and only fly for 1 hour during such operations, which would leave about 37 gallons of fuel remaining. For all other operations, including long line operations, the fuel requirement was to land with at least 100 lbs (about 14.7 gallons) of fuel remaining. At the time of the accident, the helicopter had about 14 gallons of fuel remaining. After the accident, the operator amended its risk assessment form to include the same fuel requirement for long line operations as for side pull operations.