ERA09LA194

While hovering the helicopter during the installation of a transmission wire about 70 feet above the ground, the pilot inadvertently allowed the left horizontal stabilizer to move laterally until it was beneath the wire. When the pilot attempted to climb the helicopter away from the wire, the wire hooked the stabilizer. The helicopter subsequently pitched forward and the main rotor blades and rotor mast also became entangled with the wire. The main rotor blades and tail boom then broke away from the helicopter, which spun once or twice before hitting the ground. There were no mechanical anomalies noted with the helicopter and no appreciable wind.

On March 10, 2009, at 1507 eastern daylight time, a Hughes 369D, N369RT, operated by Air2 LLC, was substantially damaged when it became entangled in a transmission wire in Lee, Massachusetts. The certificated airline transport pilot and two onboard linemen were seriously injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the local flight which began near an electrical substation close to the transmission lines. The flight was conducted under the provisions of 14 Code of Federal Regulations Part 133. According to an employee of the power company that had contracted the helicopter, the crew was involved with the installation of an overhead optical ground wire (OPGW). The OPGW was being installed on "H-frame" wood structures, about 70 feet above the ground. The employee began to take photographs of the aerial work, and noticed that as the helicopter began to move away from a newly installed OPGW, it appeared that the wire was hooked onto the left horizontal stabilizer. A photograph that he took at the same time also revealed that that the OPGW wire was hooked, in the vicinity of, and inboard the left vertical fin located on the outboard edge of the stabilizer. According to a police officer providing security at the site, he observed the helicopter take off and land numerous times from an electric substation about 500 feet west of his location. While in flight, the helicopter would fly to, and assist as necessary with the installation of the OPGW line. About 1220, the police officer observed two linemen climb the utility pole nearest the accident site "apparently to fix a pulley problem." The repair was made without assistance of the helicopter. The helicopter subsequently flew near this site several times after that, but the police officer was not sure if any linemen were onboard. About 1450, the police officer observed the helicopter again fly near the utility pole, and two linemen exited the helicopter, on to the pole. The helicopter then moved away from the pole while the linemen did some more work. The police officer also noted no mechanical anomalies with the helicopter, and no "appreciable" wind. The helicopter then returned to the pole, and the pilot positioned the left skid either against, or very close to the pole. The linemen then transitioned from the pole to the left skid. Immediately afterwards, the police officer noticed that the "tail section" of the helicopter moved laterally, to where "a small section of tail fin" was positioned under the same wire that the linemen had been working on. Then, as the helicopter slowly climbed away from the pole, a piece of the "tail section" was hooked by the wire. There was initially some slack in the wire; however, when the slack played out, the helicopter pitched forward, and the main rotor then became entangled in the wire. The main rotor blades then broke away from the helicopter, which spun one or two times before hitting the ground. Additionalphotographs of the wreckage revealed a mid-span cut, beginning at the leading edge of the left horizontal stabilizer, and wire segments wrapped multiple times around one of the main rotor blades as well as the rotor mast. The rotor blades were separated from the mast, and the tail boom was separated from the main wreckage. Weather, recorded at the airport in Pittsfield, Massachusetts, about 8 nautical miles to the north, at 1454, included overcast skies and winds from 190 degrees true at 4 knots.