Aviation Accident Summaries

Aviation Accident Summary MIA96LA200

BARTON, AL, USA

Aircraft #1

N5015T

Bell 206B III

Analysis

According to the operator of the helicopter, the purpose of the flight was to defoliate an area of vegetation near power lines by spraying chemicals. The loader of the chemicals indicated that when the flight was due to return for refueling, he observed smoke near where the helicopter was spraying. He then called 911 and reported the crash. Investigation revealed that one of the main rotor blades had contacted a power line that was 97 feet above ground level. The helicopter then descended and impact the ground nose low and rolled onto its right side where it came to rest. Impact damage to the cockpit from the main rotor blades was noted. Examination of the airframe and engine revealed no evidence of preimpact failure or malfunction. There were no known witnesses to the accident.

Factual Information

On August 3, 1996, at 1936 central daylight time, a Bell 206B III, N5015T, registered to and operated by Chem Air, Inc., collided with an unmarked power line near Barton, Alabama. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 137 aerial application flight. The helicopter was destroyed and the airline-transport rated pilot, the sole occupant, was fatally injured. The time of departure has not been determined. According to the operator of the helicopter, the purpose of the flight was defoliation of vegetation near the power lines. The loader of the chemical indicated that when the flight was due to return to refuel, he observed smoke near where the helicopter was spraying. He then called 911 and reported the crash. Examination of the crash site by an FAA inspector revealed a downed .990 inch diameter unmarked 161 KV transmission line that had been located about 97 feet above ground level. The helicopter was observed on its right side nearly inverted about 200 feet from the nearest power line tower and the downed cable was observed on the wreckage. Fire damage to grass was noted near where the downed cable contacted the ground. The tailboom which was attached to the airframe was displaced downward about 90-degrees from normal orientation and evidence of main rotor blade contact with the cockpit was noted. The helicopter was equipped with a GPS to be used to delineate spray locations. Examination of the airframe by a representative of the manufacturer revealed no evidence or preimpact failure or malfunction of the flight controls. The main rotor hub and blade assembly was separated at the mast. Examination of the fracture surface revealed evidence of overload failure. Examination of 1 of the main rotor blades revealed evidence of striations on the leading edge of the blade inboard of midspan. Both blades were damaged and evidence of electrical arching was noted on the trailing edge portion of 1 of the blade grips. A report is an attachment to this report. Examination of the engine by a representative of the manufacturer revealed no evidence of preimpact failure or malfunction. A report is an attachment to this report. A postmortem examination was performed by Steven T. Hayne, M.D., F.C.A.P., the Rankin County Designated Pathologist. The cause of death was listed as helicopter crash. Toxicological analysis of specimens of the pilot was performed by the FAA Accident and Research Laboratory. The results were negative for carbonmonoxide, cyanide, tested drugs, and ethanol. On the day and location of the accident the sunset was calculated to occur at 1954 hours. There were no known witnesses to the accident.

Probable Cause and Findings

failure of the pilot to see-and/or-avoid the obstruction (unmarked power line), while en route between the area that was being treated and the refueling location. The power line and lack of visual cues at dusk were related factors.

 

Source: NTSB Aviation Accident Database

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