N16031

HISTORY OF FLIGHT

On June 2, 1998, approximately 1610 mountain daylight time, a McDonnell Douglas 369FF, N16031, registered to Helitradewinds Inc., operated by Winco as a 14 CFR Part 133 external load, struck power lines and subsequently collided with the ground near Shoshone, Idaho. Visual meteorological conditions prevailed at the time and no flight plan was filed. The helicopter was substantially damaged. The commercial pilot was seriously injured. A crew member, who was standing on the left skid, and attached to the side of the helicopter via a safety harness, was fatally injured.

The operator reported that the purpose of the flight was to permanently attach the already strung fiber optic cable to existing power poles. The operator was hired by a construction company which was under contract to the Idaho Power Company to install 270 miles of fiber optic cable across the state.

In a written statement, the pilot reported that on the day of the accident, he remembered working at the tower where the accident occurred. The weather was visual conditions with a light wind out of the west southwest. The pilot recalled placing one of the linemen on the tower, then returning to the landing zone to pick up another lineman to take to the same tower. The pilot stated that he does not remember anything else beyond the approach to the tower, which he described as normal.

A witness, who was in his car and parked next to the highway, stated that the helicopter was hovering above the power lines and was picking up one of the lines on the top of the pole (fiber optic) with a "hook" or "shoe," and placing it from one spot to another. The witness stated that with the cable attached to the shoe, the helicopter lowered the line to the pole where a man on the pole seemed to attach the cable to the pole. When the helicopter lowered, the cable detached from the shoe. The witness stated that as the helicopter was lifting up, something "popped" and the cable "grabbed" the shoe. The helicopter twisted sideways and then continued to go over on its side. The rotor blades struck the power lines and the helicopter descended between the power lines. The witness stated that as the helicopter was descending through the power lines, the tail boom separated and the helicopter spun around about two times before colliding with the ground. The witness stated that there were no unusual sounds from the helicopter prior to the accident. The wind was blowing about five miles per hour and a light drizzle began to fall shortly after the accident. The witness stated that after the accident he was helping with the pilot, who stated that he had "no collective."

The lineman who was on the pole at the time of the accident was interviewed. The lineman reported that during the morning, travelers were hung on 12 to 16 poles in preparation for "pulling" the fiber optic cable through the travelers. After this task was accomplished, the workers broke for lunch. The lineman stated that after lunch, they rigged to "clip." The lineman described clipping as removing the fiber optic cable from the traveler and putting it in hardware that is permanently attached to the pole. Breeze dampers are then installed on the fiber optic cable about five feet away from either side of the pole for the purpose of absorbing vibration.

The lineman stated that he and another lineman were dropped off by the helicopter on two separate poles. The pilot then went to pick up the lineman who remained on the skid for the purpose of installing the vibration dampers.

The linemen stated that the linemen are transported from the landing zone to the work areas (poles) by standing on the left landing skid. Two linemen can be transported at one time. The linemen wear safety harnesses around their waists. A rope is attached to the harness. The other end of the rope attaches to one of two attach points on the left side of the fuselage. One point is located on the door post just behind the pilot's seat. The other point is located mid point, on the cabin floor. The door is removed. The linemen wear special boots with higher heels that are used to brace against the skid to prevent slipping. The top side of the skid is covered with a non-skid material.

The lineman stated that when the helicopter returned with the lineman on the skid, the pilot positioned the helicopter at the pole and next to the fiber optic cable. An external belly-mounted side pull hook assembly is used. The line (rope) was draped up and over the left landing skid and forward of the front leg. The external line is approximately five feet-five inches in length. A metal shoe is attached to the end of the external line which hangs down about four inches from the skid. The shoe is metal, and 11 inches in length, and four and a half inches wide. The shoe is "U" shaped width-wise and cradles the cable. The lineman stated that the pilot positioned the helicopter to pick up the fiber optic cable in this shoe and positioned it in the suspension shoe on the pole for him so that he could then place a pin in the suspension shoe. The pilot then descended to remove the fiber optic cable from the external line shoe. The lineman stated that he was positioned with his back to the helicopter, with the cable over his left shoulder, and was in the process of putting in a cotter key on the pin, when the helicopter moved out and behind him to start installing the vibration dampers. The lineman stated that everything up to this point was normal, when he heard a "clicking" sound. The lineman stated that "It sounded like the blades. It made a clicking sound like it just hit something." The lineman further described the noise as, "It sounded like a bike, like when you stick cards in the spoke or something like that." The lineman stated that out of the corner of his eye, he saw pieces of the helicopter flying. The lineman stated that the helicopter was behind him and should have been beside him so he knew that it was into the wires. The lineman ducked down on the pole, and when he jumped clear, the pole was "kind of shaking" and the fiber optic cable was cut. When he looked up, the helicopter was already on the ground.

The other lineman, who was on another pole, stated that he was in the process of clipping when he felt his pole move. The fiber optic cable went slack, and when he turned around, the fiber optic cable was severed and the helicopter was already spinning and into the wires.

PERSONNEL INFORMATION

The pilot reported that he began employment with Winco on April 2, 1998. The pilot flew with another pilot on board until April 24, 1998. After this time, all flights were a solo operation. The pilot's flight logbook indicates that a total time of 145 hours had been logged in the 90 days preceding the accident. The pilot stated that he had never done this type of work prior to April 1998.

The pilot reported that his prior flight experience, beginning in 1991, consisted of tuna spotting from a fishing vessel, and long-line external load operations for logging and fire suppression.

At the time of the accident, the pilot had accumulated a total flight time of approximately 5,646 hours, with approximately 907 hours in this make and model helicopter.

WRECKAGE AND IMPACT INFORMATION

The terrain surrounding the accident site was rolling-to-flat grassland with short-to-medium shrub brush vegetation. Highway 93 was within two hundred feet of the main accident site. The transmission lines ran in a north/south direction. The crew was working southerly at the time of the accident.

The main fuselage structure was located approximately 30 feet east of the power lines. The fuselage was laying on its right side. The structure had collapsed and the windshield was broken out. The instrument panel was no longer supported and laying next to the structure. The tailboom had separated forward of the tailboom attachment flange. One main rotor blade was laying lengthwise on top of the structure. Within 50 feet of the main wreckage, the tail rotor drive section, another main rotor blade, and the tailboom and portion of the tail cone were located. The remaining three main rotor blades were located up to 300 feet away from the wreckage. The tail rotor blades were located up to 700 feet away from the wreckage. One tail rotor blade was in two pieces, the other tail rotor blade was separated into three pieces. Both blades displayed wire strike signatures at the separation points. See wreckage diagram and photos.

The main rotor blades all separated at the main rotor hub assembly. Each blade is color coded and was numbered for the purpose of reference. Each blade was severely deformed. White blade number 1 displayed evidence of wire strike signatures. Blue blade number 2 displayed evidence of blue paint transfer, and was broken into two pieces. Yellow blade number three displayed evidence of striking and partially wrapping around the tailboom. Impact signatures matching rivet indents from the tailboom were noted on the blade. Green blade number four was twisted and found on top of the main wreckage structure. Red blade number 5 displayed evidence of wire strike signatures at the blade tip. The top of the dog house was damaged and evidence indicates main rotor contact to the aft boom fairing. Each of the main rotor blade pitch change links were damaged either in tension or were bent. Further impact damage was noted to the main rotor feathering bearings which displayed rotational strikes; the hub subassembly was damaged. The main rotor hub assembly turned freely on the mast and the swashplate double-row bearing rotated freely.

The main rotor collective control was found to move from full up to full down, with some upper restrictions noted. The collective jack shaft was damaged four inches from the torque tube. The pilot's twist grip was not damaged and the collective friction...