Aviation Accident Summaries

Aviation Accident Summary SEA96TA213

ST REGIS, MT, USA

Aircraft #1

N47MA

Bell 206B-3

Analysis

The helicopter sustained substantial damage when it struck wires during a fire suppression activity for the U.S. Forest Service. The pilot reported that his water bucket malfunctioned on his seventh load, while performing fire suppression, and he was unable to drop its water. On his way back to the helibase, he diverted from a direct return. He reported that he descended and circled with the intention of putting his bucket down on an abandoned railroad grade to tip it over and empty it. An eyewitness advised that the pilot appeared to be descending and circling to fill his bucket in a pond just across the railroad grade. About 80 feet above the pond, the helicopter struck a powerline with the main rotor blades, severing three conductors of a main distribution line. About 80 feet further west along the powerline, the main rotor blades severed the messenger wire in two places, about 12 feet apart. The helicopter remained controllable and the pilot continued a right turn, descending to a landing on the railroad grade.

Factual Information

On September 13, 1996, approximately 1356 mountain daylight time, a Bell 206B3 helicopter, N47MA, registered to Minuteman Aviation of Conrad, Montana, and performing public-use aerial firefighting bucket operations under contract to the U.S. Forest Service, struck wires during an aerial reconnaissance of a pond approximately 1/2 mile south of St. Regis, Montana. The pilot subsequently performed a forced landing on a road. The pilot was not injured but the helicopter was substantially damaged in the occurrence. Visual meteorological conditions were reported at Missoula, Montana, at the time of the accident. The pilot reported that his water bucket malfunctioned on his seventh load while performing fire suppression, and he was unable to drop its water. On his way back to the helibase, he diverted from a direct return. He reported that he descended and circled with the intention of putting his bucket down on an abandoned railroad grade to tip it over and empty it. An eyewitness advised that the pilot appeared to be descending and circling to fill his bucket in a pond just across the railroad grade. Just over the pond, the helicopter struck a powerline at a point about 80 feet above the pond with the main rotor blades, severing the three conductors of a main distribution line. About 80 feet further west along the powerline, the main rotor blades severed the messenger wire in two places about 12 feet apart. The helicopter remained controllable and the pilot continued a right turn, descending to a normal landing on the railroad grade.

Probable Cause and Findings

failure of the pilot to maintain clearance from electrical transmission lines. The proximity of transmission lines was a related factor.

 

Source: NTSB Aviation Accident Database

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