History of Flight
On January 22, 2009, about 1030 eastern standard time, a Hughes OH-6A helicopter, registered N4191A, struck high tension power lines and impacted the ground near Monroe, North Carolina. The helicopter had departed Monroe Regional Airport (EQY) about 1000. The flight was operated under 14 CFR Part 91 in visual meteorological conditions with no flight plan filed.
According to airport employees, the two pilots initially planned to fly to Columbia, South Carolina, but changed their plans to remain local and practice viewing power lines while calibrating a GPS unit. Witnesses reported seeing the helicopter at low altitude, with one observing the impact with the power lines followed by blue flashes and a boom. Another witness heard a buzzing sound for about 20 seconds, then a loud bang and the sound of impact.
The accident pilot stated that earlier that morning, the sample mission was canceled due to weather. The pilots decided to simulate a mission flying between 75 and 100 feet agl. The GPS had reverted to factory defaults due to work the previous night, causing obstacle warnings. The pilot transferred control to the pilot-rated-passenger and leaned forward to adjust the GPS. While doing so, he felt a violent shaking and heard a loud noise.
GPS data showed the helicopter on a southwesterly track paralleling a power line, with the last eight data points indicating a right turn. The final recorded point placed the helicopter near the accident location.
Personnel Information
The certificated flight instructor, aged 35, held commercial and flight instructor certificates for rotorcraft-helicopter, with 1,100 total flight hours, including 1,000 as pilot-in-command and 110 hours in the accident helicopter model. His most recent flight review was October 2008, and his second-class medical certificate was issued July 2007.
The commercial pilot-rated-passenger, aged 46, held a commercial pilot certificate for rotorcraft-helicopter. His most recent second-class medical certificate was issued May 2008, reporting 250 total flight hours and 50 hours in the preceding six months.
Aircraft Information
The helicopter was manufactured in 1967 for military use and issued an FAA standard airworthiness certificate on March 18, 1997. It was equipped with an Allison 250-C10D turbo-shaft engine, overhauled in May 1994 with 3,412 total hours at that time. The last maintenance logbook entry was dated June 2, 2007, showing 5,623.9 total hours. A local mechanic reported performing a 100/300-hour/annual inspection on June 26, 2008, at 5,660.7 total hours, providing a checklist and logbook entry copy.
Meteorological Information
The 1053 weather observation at Monroe Regional Airport reported wind from 240 degrees at 5 knots, clear skies, 10 miles visibility, temperature 2°C, dew point -8°C, and altimeter 30.17 inches of mercury.
Wreckage and Impact Information
The helicopter came to rest on its left side in an open field beneath overhead high tension power lines. The main rotor separated and was found about 75 feet from the wreckage. The cockpit, cabin, and tailboom were damaged by impact forces. The right side pilot door support post exhibited marks and compression reducing occupant survivability space. Power line photos showed five intact lines and two severed grounding wires.
Medical and Pathological Information
Postmortem examination of the pilot-rated-passenger determined the cause of death as blunt force traumatic injuries. Forensic toxicology detected dihydrocodeine, hydrocodone, hydromorphone, and ibuprofen in specimens. Medical records showed treatment for kidney stones, high blood pressure, and right knee arthritis, with a prescription for Vicoprofen the day before the accident. The pilot's most recent medical application (May 2008) reported no medication use and no medical history items, including high blood pressure or kidney stones.