ERA13LA437

The pilot’s loss of helicopter control while hovering for reasons that could not be determined during postaccident examination of the helicopter, which was limited due to postcrash fire damage.

After about a 10-minute flight, the pilot returned to the airport and attempted to land the helicopter. A witness reported that, when the helicopter was about 30 ft above the ground, it seemed to be "unstable" and began to oscillate from side to side. The pilot then aborted the landing, flew for a few minutes, and then returned for landing. The witness reported that during this landing attempt, when the helicopter was again about 30 ft above the ground, it began spinning to the left and then impacted the ground. According to a friend of the pilot, about 2 months before the accident, the pilot had experienced a similar loss of control in the accident helicopter in which the helicopter rapidly spun to the left three times just before landing. The pilot then gained altitude, regained control, and flew away from the landing site. The pilot checked the controls and then came in and landed without incident. The pilot told his friend that, after the helicopter started spinning left, he shut off the automatic throttle governor and was able to recover. When the pilot was interviewed about 1.5 years after the accident, he reported that, during the previous flight when he lost helicopter control, he believed that he came in a little too fast and, since the governor did not work well and the helicopter did not have a lot of horsepower to correct or recover, that could have caused the spins. Regarding the accident, he stated that "I would like to think it was the helicopter, but it could have been me." The majority of the helicopter, including the engine governor and engine management system, was consumed by a postcrash fire and could not be examined. Examination of the surviving components did not reveal any evidence of a preexisting failure or malfunction of the flight control system or engine. Although the loss of control was consistent with the pilot failing to maintain control during the landing approach and experiencing a loss of tail rotor effectiveness, the postcrash fire damage precluded determination of whether a mechanical failure played a role in the loss of control.

HISTORY OF FLIGHT On September 29, 2013, at 1109 eastern daylight time, an unregistered Mosquito XEL Helicopter was substantially damaged during landing at Lazy Springs Recreation Park, Felda, Florida. The non-certificated pilot was seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight, which was operated under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. According to a witness, the pilot liked to fly the helicopter whenever he had a chance. On the day of the accident, the pilot had trailered the helicopter into the park to do some flying in the local area. The takeoff was uneventful, but instead of the pilot going out, and flying around the area for 30 to 45 minutes which was his usual habit, approximately 10 minutes later he returned and attempted to land. As the helicopter was approximately 30 feet from touchdown it seemed to be "unstable" and began to oscillate from side to side. The pilot then aborted the landing and flew off for a few minutes, and then returned. This time as the helicopter was once again about 30 feet from touchdown, it began spinning to the left and impacted the ground. A postcrash fire then ensued. The pilot was pulled out of the wreckage by the witness and another person, and was later airlifted to a hospital. PERSONNEL INFORMATION The pilot did not hold any type of pilot certificate or rating for rotor wing aircraft. He had attended a basic helicopter orientation course which consisted of 24 hours of ground instruction and 10 hours of flight instruction in a Schweizer 300C which was designed to familiarize the course attendees with safety procedures, guidelines, aerodynamic forces, forces in flight, flight control systems, safety of flight, hazards of helicopter flight, basic navigation, aviation physiology, federal aviation regulations, aeronautical decision making, and pilot judgment. Review of pilot records also revealed that he had received instruction prior to the course in a Robinson R22, and that he had received 14 CFR Part 61, Special Federal Aviation Regulation Number 73 (SFAR 73) required ground training which required that before a pilot could manipulate the flight controls of a Robinson R22 or R44 Helicopter, they must be trained in energy management, low rotor rpm which could lead to a low rotor rpm stall, and low or negative G, which could lead to mast bumping. Further review of pilot records also indicated that he had received approximately 20 hours of dual instruction and at the time of the accident, he had accrued approximately 40 total hours of flight time. AIRCRAFT INFORMATION The helicopter was of conventional composite and metal construction. The airframe was made of fiberglass in a vinylester matrix. It was powered by a 60 horsepower, two cycle, two cylinder engine, equipped with a 180-watt alternator which provided power to run the helicopters electrical system. The drive train's primary reduction was bolted directly to the engine. A centrifugal clutch on the engine crankshaft permitted startup of the engine without a load from the rotor system. Power was transmitted from the clutch to the driven pulley of the reduction through a cogged belt. The driven pulley housed a sprag clutch which would permit the rotor to overspeed the engine during autorotation. Review of the helicopter manufacturer's records revealed that the helicopter was manufactured in 2012 and had been equipped with floats. It weighed 314 pounds which would allow it to be operated under 14 CFR Part 103 ultralight regulations however, the pilot had changed the configuration of the helicopter by removing the floats, and adding an engine governor which rendered it ineligible for operation under Part 103 and placed it into the experimental category. This would have required the pilot to possess a private pilot certificate, the helicopter to be registered with the Federal Aviation Administration (FAA), and an airworthiness inspection to be performed by an FAA designated airworthiness representative prior to the first flight, as described in FAA Advisory Circular (AC) 20-27F, "Certification and Operation of Amateur Built Aircraft." At the time of the accident the helicopter and engine had accrued approximately 20 hours of total operating time. METEOROLOGICAL INFORMATION The recorded weather at Southwest Florida International Airport (RSW), located approximately 17 nautical miles west of the accident site, at 1053, included: winds from 070 degrees at 10 knots, 10 miles visibility, sky clear, temperature 28 degrees C, dew point 21 degrees C, and an altimeter setting of 29.98 inches of mercury. WRECKAGE AND IMPACT INFORMATION Examination of the accident site and wreckage revealed that the helicopter came to rest on a 15- degree embankment on the edge of a 27 acre lake, on a magnetic heading of 095 degrees. The majority of the helicopter including the cabin, seat, floor panel, and tail boom sections were consumed by the postcrash fire. The rotor head showed marks consistent with mast bumping. The control mechanism was connected and moved freely. The swash plate was consumed by post-crash fire. Rotor blade "A" was delaminated and thermal damaged from the blade root to 5 feet outboard. The rotor blade was still connected to the rotor hub. There was no chord or span wise scratching on the blade. The pitch change rod was connected and the pitch change horn was bent about 15- degrees upward. The spindle moved freely. Rotor blade" B" was consumed by post-crash fire, delaminated, and was separated from the spar 13 inches outboard the blade root. There was no chord or span wise scratching. The blade root was still connected to the spindle, which moved freely. The pitch horn was bent about 45- degrees upward and the pitch rod connector was fractured in a manner consistent with tension overload. The No. 3 sprocket was connected to the secondary drive system. The coupler connecting the lower shaft to the splitter gear box was consumed by post-crash fire. There was drive belt residue on the main rotor No. 3 and No.4 sprockets. Engine continuity was not verified due to thermal damage to the engine accessories and the main engine casing. Three motor mounts were present, with the fourth motor mount retaining bolt having been sheared off. Two motor mount retaining bolts on the torque side of the engine were also bent. Both engine carburetors were consumed by the post-crash fire, and were unrecognizable. The muffler was attached to the engine and was unremarkable. The primary drive belt was attached to the No. 1 and No. 2 sprockets, and was thermal damaged. Control continuity from the flight control pedals to the tail rotor pitch links was verified. Control continuity from the cyclic and collective control was not verified due to consumption of the mechanisms from the post-crash fire. The tail rotor blades were connected to their respective pitch links, and were moved freely through their range of travel. The tail rotor gear box, pitch links, and control rods were thermal damaged. The tail rotor blades were free of chord or span wise scratching. The splitter gear box was thermal damaged and the jaw couplers were unremarkable. The dampener in between the couplers was consumed by the post-crash fire. From the splitter gear box to six feet aft of the splitter gear box, the tail rotor drive shaft was either melted or thermal damaged. The three internal carrier bearings were present and thermal damaged. From the tail rotor gear box to a point located 22 ½ inches forward, a fracture of the tail rotor drive shaft, consistent with bending overload and thermal damage was present. The right landing skid was thermal damaged, and otherwise unremarkable. The left landing skid was thermal damaged on the rear left side. The forward cross bow was thermal damaged but remained connected to the "T" fittings.