History of Flight
On October 1, 2011, about 1255 mountain daylight time, a Robinson Helicopter R66, registration N266CY, was destroyed during an in-flight breakup while in cruise flight near Philip, South Dakota. The private pilot, the sole occupant, was fatally injured. The helicopter was registered to P.P. and J. LLC., of Gillette, Wyoming. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight conducted under 14 CFR Part 91. The cross-country flight originated from Gillette-Campbell County Airport (GCC) around 1105, destined for Winner Regional Airport (ICR) in Winner, South Dakota.
A friend of the pilot reported that the pilot appeared in good health and excited about the flight, having topped off the fuel before departure. About an hour and a half later, the pilot called the friend during the flight, reporting he was between Wall and Philip, South Dakota, and asked if Philip Airport (PHP) had jet fuel. The friend called back to report it did not. The pilot reported no anomalies during the conversations.
An eyewitness about 2 miles northwest of the accident site observed the helicopter flying west to east along a river at approximately 1,000 feet AGL. He heard nothing abnormal as it passed, then saw it turn left before disappearing behind trees. About 20-30 seconds later, he heard a noise like an exploding propane tank.
Personnel Information
The pilot, aged 64, held a private pilot certificate with airplane single and multi-engine land, rotorcraft helicopter, and instrument airplane ratings. He was issued a third-class medical on November 3, 2009, with a limitation requiring glasses for near vision. His flight logbooks were not recovered. On an insurance application dated February 4, 2011, he estimated 3,600 total flight hours, with 60 hours in the last 90 days, including 210 hours in helicopters and 22 hours in the Robinson R66. His last biannual flight review was on May 5, 2010. Two instructors provided instruction in the R66 for a total of about 3 hours, but neither provided a signoff, though none was required. SFAR 73-2 applied to R-22 and R-44 but not the R66.
Aircraft Information
The 2011-model Robinson R66, serial number 0010, held a standard airworthiness certificate. It was powered by a Rolls-Royce RR300 turbo-shaft engine, serial number RRE200013. The most recent 100-hour inspection was completed on June 6, 2011, at 82.6 total airframe and engine hours.
Meteorological Information
At 1255, the automated weather at PHP (3 nautical miles northeast of the accident site) reported wind from 150 degrees at 6 knots, 10 miles visibility, clear skies, temperature 84°F, dew point 39°F, and barometric pressure 30.00 inHg.
Wreckage and Impact Information
The wreckage was spread over approximately 1,520 feet by 600 feet on rolling ranch land. The main rotor head with blades came to rest 513 feet from the main wreckage, which consisted of the fuselage, engine, and tail rotor assembly. The airframe was severely damaged by fire and impact. Scoring and deformation on door frames suggested contact with main rotor blades. The cabin was nearly consumed by post-crash fire. The collective was in a full up position; the fuel cutoff valve was extended ¼ inch from full down. A steel shot bag was found under cabin remains.
The tailcone was mostly consumed by fire forward, with the aft section intact except for a separated last bay. The empennage separated from the tail cone. Both skid toes and forward struts separated; rear struts remained attached. The fuel system was mostly destroyed. The fuel bladder was consumed; the finger screen was clear. All main rotor flight control rod ends were secure; disconnects were consistent with overload or thermal damage. The main rotor gearbox had thermal damage and two holes; output shaft rotation was limited. The main rotor separated about 8 inches below the teeter bolt. Both blades showed bending and damage; one blade had separated skins and honeycomb. The engine was disconnected from the structure; the compressor showed no pre-impact anomalies. The engine monitoring unit was fire-damaged and yielded no data.
Medical and Pathological Information
An autopsy on October 3, 2011, concluded the cause of death was blunt trauma injuries. Toxicology testing was negative for ethanol; losartan (a blood pressure medication) was detected in the liver.
Tests and Research
Examination of main rotor components at the NTSB materials lab revealed features consistent with a mast bump event, including overstress separations. The engine teardown found no pre-impact failures that would prevent normal operation; N1 and N2 coupling adapters exhibited overstress fractures. Examination of hydraulic servos found no pre-impact anomalies. Swab samples tested negative for bird remains.