20170314003049A

On March 14, 2017, at 1546 eastern daylight time, an MD helicopters model 369FF helicopter, registration number N530KD, impacted terrain during a power line construction flight. The pilot was fatally injured and the helicopter was destroyed. The helicopter was registered to ^robin m rogers^ and operated by rogers helicopters, inc., under the provisions of 14 CFR part 133 as an external load operation. Visual meteorological conditions prevailed at the time of the accident and no flight plan was filed.

The white county airport (mcx) recorded at 1535: wind from 350 at 12 knots gusting to 19 knots, 7 statute miles visibility with light snow, broken clouds at 3,500 ft, overcast cloud layer at 4,800 ft, temperature 27F, dew point 16F, and altimeter setting 30.25 inches of mercury. Three witnesses independently reported gusting wind at the time of the accident. A company crewmember sitting in a vehicle with windows open stated that at the time of the accident he felt the wind pause momentarily, followed by a gust.

The purpose of the flight was to thread a cable through a series of towers. Using ground equipment, the cable would be used to pull a larger cable, which in turn would then pull a final set of 6 cables. The term sock line is the nomenclature applied to the single cable being threaded by the helicopter.

At the time of the accident, the sock line was fed from a truck-mounted reel nine towers away, approximately 11,000 feet away. A long metal bar (needle) was used to thread the sock line through the towers. The needle has 2 eyes welded to it, one near the center and the other at the end distal from the sock line attachment. Both eyes have a projection, or barb, pointing in the direction of the sock line. This barb is used to hook the needle to the tower.

The helicopter pulled the sock line from one tower to the next, threading it through each tower, unwinding the reel. When the helicopter arrived at the next tower and ceased pulling, a brakeman at the reel stopped it from unwinding. The pilot and the brakeman were in radio contact, and coordinated the unwinding action.

The helicopter was equipped with a side pull hook assembly and a cargo hook. The cargo hook was attached to a 50 foot long line with a grappling hook (grapple). The pilot hooked the grapple to the needle using the center eye of the needle.

A witness provided a video recording of the accident flight. The video showed the pilot attempt to hook the needle to the tower structure. The helicopter seemed to struggle to stretch the sock line to the tower. The first attempt failed. A second attempt appeared to miss the desired contact point. The helicopter's altitude and attitude varied presumably due to wind gusts. The attitude of the helicopter became more variable. The nose pitched up, and the helicopter began moving downwind. This action moved the needle toward the tower. The needle contacted the ladder rung assembly on the tower. The ladder is near the intended needle placement point. The helicopter continued moving downwind while the needle became anchored to the tower. The helicopter became tethered to the tower and lost control. The longitudinal axis of the helicopter became nearly vertical, nose up, while still tethered to the tower. The needle eye that the grapple was attached to broke free from the needle, whipping the 50 foot line and grapple away from the tower, sending the line under the helicopter. Free of the tether, the pilot appeared to have levelled the helicopter while descending, however the helicopter descended into the line. The line tangled with the main and tail rotors, shearing the blades, resulting in the helicopter falling approximately 50 feet to the ground.