Accident Details
On March 10, 2009, at 1507 eastern daylight time, a Hughes 369D helicopter, registration N369RT, operated by Air2 LLC, was substantially damaged when it became entangled in a transmission wire near an electrical substation in Lee, Massachusetts. The certificated airline transport pilot and two linemen onboard were seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight, which began near the substation. The flight was conducted under 14 Code of Federal Regulations Part 133.
Sequence of Events
According to an employee of the power company that had contracted the helicopter, the crew was installing an overhead optical ground wire (OPGW) on H-frame wood structures about 70 feet above the ground. The employee photographed the helicopter after noticing that the wire appeared to be hooked onto the left horizontal stabilizer. The photograph showed the OPGW hooked in the vicinity of, and inboard of the left vertical fin.
A police officer providing security observed the helicopter taking off and landing numerous times from the substation, about 500 feet west. Around 1220, the officer saw two linemen climb a utility pole near the accident site to fix a pulley problem without helicopter assistance. The helicopter flew near the site several times afterward.
About 1450, the helicopter flew near the pole, and two linemen exited onto the pole. The helicopter moved away while the linemen worked. The officer noted no mechanical anomalies and no appreciable wind. The helicopter returned, and the pilot positioned the left skid against or very close to the pole. The linemen transitioned from the pole to the skid. Shortly after, the officer saw the helicopter's tail section move laterally, positioning a small section of tail fin under the same wire. As the helicopter climbed away, the wire hooked the tail section. When slack played out, the helicopter pitched forward, and the main rotor entangled in the wire. The rotor blades broke away, and the helicopter spun one or two times before hitting the ground.
Wreckage Examination
Additional photographs revealed a mid-span cut beginning at the leading edge of the left horizontal stabilizer. Wire segments were wrapped multiple times around one main rotor blade and the rotor mast. The rotor blades separated from the mast, and the tail boom separated from the main wreckage.
Weather Conditions
Weather recorded at Pittsfield Municipal Airport, about 8 nautical miles north, at 1454 included overcast skies and winds from 190 degrees true at 4 knots.