NTSB Factual Report

On July 5, 2010, at 1745 central daylight time, a Robinson R-44, N857PM, collided with a guy wire near Marion, Kentucky. The certificated commercial pilot was fatally injured. The helicopter came to rest in a field and was substantially damaged by post crash fire. The helicopter was registered to and operated by Forest Tech LLC., under the provisions of 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual meteorological conditions prevailed, and no flight plan was filed. The flight departed the private strip at 1743.

According to a witness, the pilot was conducting an aerial spray operation in a corn field. He observed the helicopter take off and fly to the edge of the field to begin an aerial application run. The witness turned around and heard a loud “pop”. He turned back around and observed the helicopter collide with a power line guy wire and the ground before bursting in flames.

The pilot, age 55, held a commercial pilot certificate for rotorcraft helicopter issued on March 6, 2009, and a second-class medical certificate issued on September 17, 2009, with the limitation, must wear lenses for distant vision and have glasses for near vision. A review of the pilot's logbook by the FAA revealed the pilot logged 532.9 hours in type. The pilot logged 611.3 total flight hours of which 190.1 hours were aerial application. The pilot had flown 28 hours within the last 90 days.

The four-seat, skid equipped helicopter, serial number 1034 was manufactured in 2001. It was powered by a Lycoming O-540, 250-horsepower engine. A review of the helicopters logbooks by the FAA revealed the last annual inspection was conducted on May 14, 2010, at a recorded tachometer time of 1404.8 hours. The hour meter and tachometer were destroyed by post crash fire and the current airframe hours could not be determined.

Examination of the crash site revealed the helicopter impacted the top ground cable of a high voltage power line about 35 feet 6 inches above ground level. The top cable separated and exhibited fracture signatures consistent with an overload failure. The lower cable was also contacted but did not break. The wreckage path extended approximately 75 feet and was oriented on a heading of 275 degrees magnetic. The main section of the wreckage was located about 100 feet beyond the initial impact. The longitudinal axis of the helicopter was oriented about 310 degrees magnetic. The cockpit, main cabin and engine area were consumed by fire.

The main rotor blades, engine, landing gear skids, tail boom and rotor section were accounted for. Both main rotor blades were damaged and exhibited cable scarring on the rotor blades. The main rotor blades separated from the mast outboard of the mast attachment points. The main rotor pitch change links were present and the main rotor mast exhibited cable scarring.

The tail boom aft of the fuselage and the tail rotor assembly was not damaged. The tail rotor drive shaft was separated at the forward attachment coupling. The coupling was not damaged and was fire damaged. Tail rotor drive shaft continuity was established from the forward attachment coupling to the tail rotor assembly.

Examination of the engine revealed the engine was fire damaged and remained attached to the engine mounts. All external hoses, lines and V-belts were fire damaged. The magnetos were fire damaged. The engine was partially disassembled. The top and bottom ignition harness were fire damaged. The top and bottom spark plugs were removed and exhibited light gray combustion deposits. The engine was rotated by hand, and compression and suction was obtained at all cylinders. The rocker arms and valves moved when the crankshaft was rotated. Valve train continuity was obtained throughout the engine. The oil filter was removed, opened, and was free of contaminants. The oil screen was removed and was free of contaminants. The fuel system and ignition system was not tested due to fire damage.

An autopsy was performed on the pilot on July 6, 2010, by the Western Kentucky Regional Examiner’s Office, Madisonville, Kentucky. The cause of death was multiple blunt force injuries.

The Federal Aviation Administration Bioaeronautical Sciences Research Laboratory, performed toxicology testing on specimens from the pilot. No carbon monoxide or cyanide was detected in the blood, and no ethanol was detected in the vitreous. Azacylonol was detected in urine but was not detected in the heart. Diphenhydramine 0.032 (ug/ml, ug/g) was detected in the blood but was not detected in the urine. Ibuprofen was detected in the urine.

NTSB Probable Cause

The pilot's failure to maintain clearance from power lines during an aerial application flight.