NTSB Identification: FTW96FA060.
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Accident occurred Tuesday, December 05, 1995 in THIBODAUX, LA
Probable Cause Approval Date: 11/11/1996
Aircraft: McDonnell Douglas 369E, registration: N16089
Injuries: 1 Fatal,1 Minor.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The helicopter was hovering at 55 feet agl, parallel to a power line cable, facing east-southeast. The wind was from 200 to 210 degees at 5 to 10 knots. The rotation plane of the tail rotor blades was about 38 inches from the nearest wire. A crew member, held by a safety harness, was working from the left side of the helicopter intalling an overhead ground wire in roller blocks. The crew member's work platform was about 4 inches from the overhead ground wire when, as the pilot described, 'the cyclic suddenly moved to the left and maybe slightly forward. (The helicoper) immediately started moving to the left and into the pole and line.' The pilot further stated that he was 'trying to stop the cyclic' and move it to the right; however, 'cyclic movement to the right had a restriction,' and the 'helicopter struck the pole and/or the shield wire, pivoted to the left and up, over the shield wire,' and 'began to spin.' It impacted the ground, fire erupted, and the helicopter came to rest inverted. The pilot escaped the fire, but the crew member sustained fatal injuries. Investigation revealed the helicopter's center-of-gravity was left-lateral (-2.67 inches), the limit was -3.00 inches, and about 25% of right cyclic travel was available to the pilot. A gouge mark was found on the side of the power pole matching the helicopters work flatform. No preexisting cracks or discontinuities were found in unburned flight controls, although most of the controls were consumed by fire.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: failure of the pilot to maintain clearance from the power line and utility pole. The gusty/crosswind (weather) condition was a related factor. Full narrative available
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