Aviation Accident Summaries

Aviation Accident Summary MIA97LA073

WILLISTON, FL, USA

Aircraft #1

N3495

Cress CRESS B-8-M (BENSEN)

Analysis

After the gyroplane took off, witnesses heard it maneuvering in the vicinity of the airport. Subsequently, the gyroplane descended, impacted the runway, and came to rest on its side. Examination of the flight controls revealed no evidence of a preimpact failure or malfunction. The witnesses said they heard an increase and decrease in engine power, twice before hearing the engine backfire, shortly before impact with the runway. Examination of the main rotor revealed compression buckling on the bottom side of each blade.

Factual Information

On January 24, 1997, about 1739 eastern standard time, a homebuilt gyroplane, N3495, registered to a private individual, crashed while maneuvering at the Williston Municipal Airport, Williston, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the flight. The gyroplane was destroyed and the student pilot was fatally injured. The flight originated about 9 minutes earlier. According to an FAA inspector who examined the accident site, the flight departed down runway 22 flying about 40-50 feet above ground level, then at the intersection of runway 14, the pilot initiated a left turn. Witnesses heard the engine power increase then decrease twice then heard a "popped" sound similar to an engine backfiring just before the gyroplane impacted the ground. There were no eyewitnesses to the accident. The gyroplane crashed on runway 14 while on an easterly heading. Two ground scars on the runway were noted to be perpendicular to the flight path and both of the wooden propeller blades were observed to be shattered. One of the main rotor blades was separated but was located about 10 feet south of the crash site. Examination of that blade revealed it was bent downward at about a 45-degree angle about midspan of the blade and the leading edge near the tip was displaced aft. Examination of the blade attached to the mast assembly revealed compression wrinkles on the bottom side of the blade. Fuel and oil stains were noted on the runway beneath the wreckage. Examination of the flight controls revealed no evidence of preimpact failure or malfunction. A postmortem examination of the pilot was performed by Carolyn M. Hopkins, M.D., of the Gainesville Medical Examiners Office. The cause of death was listed as massive blunt traumatic injuries. A toxicological analysis was performed on specimens of the pilot by Smith Kline Beecham Clinical Laboratories. All results were negative. Toxicological analysis was also performed by the FAA Toxicology and Accident Research Laboratory. The results were negative for volatiles and tested drugs. Testing for carbon monoxide and cyanide were not performed due to a lack of a suitable specimen.

Probable Cause and Findings

failure of the pilot to maintain rotor rpm, while maneuvering, which resulted in an uncontrolled descent and collision with terrain.

 

Source: NTSB Aviation Accident Database

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