Aviation Accident Summaries

Aviation Accident Summary FTW97LA270

AMELIA, LA, USA

Aircraft #1

N3892R

Bell 206L-1

Analysis

After completing hover checks, the pilot initiated a takeoff through a cut in the trees. At about 60 feet AGL and 40 knots, a 'loud bang' occurred. The helicopter 'yawed left and the rotor rpm began to decay.' The pilot initiated an autorotation and made a 'hard/steep right turn' towards the only available landing area 75 yards to his right rear. The helicopter landed hard on its right skid and rolled over coming to rest on its right side. The engine was test run, and its performance exceeded new engine specifications. Following the test run, the engine was partially disassembled and inspected. Indications of blood and flesh were found in the impeller and through the compressor air discharge tubes. This finding was consistent with other engines that had been examined and found to have ingested green tree frogs. The pilot also reported that during his preflight inspection, he did not observe any green tree frogs.

Factual Information

On July 17, 1997, at 0630 central daylight time, a Bell 206L-1 helicopter, N3892R, registered to and operated by Petroleum Helicopters, Inc., as a Title 14 CFR Part 91 flight, was substantially damaged during a forced landing following a loss of engine power near Amelia, Louisiana. Visual meteorological conditions prevailed, and a company flight plan was filed for the company crew change flight. The airline transport rated pilot and his one passenger were not injured. The flight was originating at the time of the accident. During a personal interview conducted by the NTSB investigator-in-charge and on the enclosed Pilot/Operator Accident Report, the pilot stated that during the first start of the day he encountered a TOT (turbine outlet temperature) problem. After shutdown, maintenance found a wire problem with the TOT system. Maintenance repaired the wire, and after a FOD inspection, a maintenance operational check was performed. No further problems were noted with the TOT, and the helicopter was released for flight. The pilot further reported that the ensuing start and runup were normal. He hovered the helicopter into position for a Bayou South departure. After completing hover checks, he initiated a takeoff through a cut in the trees. At about 60 feet AGL and 40 knots, a "loud bang" occurred. The helicopter "yawed left and the rotor rpm began to decay." He initiated an autorotation and made a "hard/steep right turn" towards the only available landing area 75 yards to his right rear. The helicopter landed hard on its right skid and rolled over coming to rest on its right side. Examination of the helicopter by the FAA inspector revealed that the tailboom was wrinkled, one main rotor blade had separated, and the right skid and underside of the fuselage were damaged. On July 19, 1997, the engine was test run at the Petroleum Helicopters, Inc., maintenance facility, and its performance exceeded new engine specifications. Following the test run, the engine was partially disassembled and inspected. Indications of blood and flesh were found in the impeller and through the compressor air discharge tubes. This finding was consistent with other engines that had been examined and found to have ingested green tree frogs. The pilot also reported that during his preflight inspection he did not observe any green tree frogs.

Probable Cause and Findings

partial loss of engine power due to frog(s) being ingested into the engine. Factors relating to the accident were: the lack of altitude and lack of suitable terrain for a forced landing.

 

Source: NTSB Aviation Accident Database

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