History of Flight
On September 19, 2010, at approximately 1307 eastern daylight time, an unregistered, experimental, amateur-built Schulman Mosquito XEL helicopter sustained substantial damage from a post-crash fire after colliding with trees in a heavily wooded area near East Monponsett Pond, Halifax, Massachusetts. The pilot died in a hospital 24 days after the accident. No flight plan was filed, and visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 91 personal flight. The helicopter had departed from Cranland Airport (28M) in Hanson, Massachusetts, about half a mile from the accident site, earlier that day.
Witnesses on a nearby lake observed the helicopter flying over and around the lake, at times at low altitude. The helicopter maneuvered over a swampy area with trees and was seen hovering just above the treetops. It was observed yawing its tail boom left and right approximately 15 degrees each way, followed by tipping of its main rotor blades left and right. The helicopter then entered a spin and nosed over, impacting the trees.
A representative of the Mosquito aircraft manufacturer and training facility in Florida stated that the pilot purchased the aircraft as a kit from them in 2009 and received a service offer allowing the owner/builder to assemble the helicopter under manufacturer supervision. The manufacturer also offered 10 hours of initial flight training, which the pilot declined, stating he had experience flying a Robinson R-22 rotorcraft with a friend. The representative observed the pilot fly the helicopter when it was nearly completed, noting that the pilot demonstrated some rotorcraft flying skills but also had difficulty with power and flight control management, typical of pilots accustomed to flying rotorcraft with a governor (the R-22 has one; the Mosquito XEL does not). The pilot departed the facility before the wiring was fully completed, and he and the representative remained in routine contact for guidance on completing the wiring and accessory installation. The representative recalled the pilot mentioning he had flown the helicopter about 12 hours since leaving the manufacturer's facility.
Personnel Information
The pilot held a commercial pilot certificate with single-engine and multi-engine land ratings, and instrument rating. His medical certification was revoked on February 20, 2007, for medical reasons; at that time he reported 4,000 total flight hours. He did not hold a helicopter rating. A copy of the pilot's flight logbook was not provided.
Aircraft Information
The Mosquito XEL, serial number 1097, is an ultralight helicopter sold with floats on the skids. To comply with 14 Code of Federal Regulations Part 103 weight restrictions, the helicopter must be operated with floats installed. Without floats, it falls under the experimental homebuilt category, requiring registration and an airworthiness certificate. The pilot must hold an FAA rotorcraft rating and a medical certificate to operate the helicopter. At the time of the accident, the floats were not installed; the helicopter was unregistered and lacked airworthiness certification. A copy of its maintenance logbook was not provided.
Meteorological Information
The closest official weather observation was at Plymouth Municipal Airport (PYM), 8 miles southeast of the accident site. The 1252 METAR reported wind from 260 degrees at 5 knots, visibility 10 statute miles, few clouds at 2,700 feet above ground level, temperature 24°C, dew point 14°C, and altimeter 30.09 inches of mercury.
Wreckage and Impact Information
The responding FAA inspector stated that the aircraft came to rest inverted with the top of the main rotor facing the ground in a heavily wooded swamp area. Most of the fiberglass fuselage was consumed by the post-crash fire. Both rubber serpentine drive belts were intact, with the main rotor belt melted to the pulley and reinforcing cord drooping from the melted remnants. A section of the tail boom remained intact; a 2-foot section of the tail boom with the tail rotor gearbox was found 25 yards northwest of the main wreckage. A 2-foot section of the tail rotor drive shaft was sheared off and found 5 feet from the main wreckage.
Tree damage signatures were observed where the broken tail boom section and gearbox were thrown. One carbon fiber tail rotor blade was found adjacent to the remaining tail boom at the main wreckage; the other was halfway between the main wreckage and the gearbox. Both carbon fiber blades were broken at their root where bonded to the mounting pad. The tail rotor gearbox was impact-damaged but rotated freely. The aluminum main rotor blades remained intact with dents and bends on top and bottom; no leading-edge impact damage was noted.
A wreckage examination by the helicopter's manufacturer representative, with FAA oversight, revealed no evidence of failures or malfunctions that would have prevented normal operations prior to tree impact.
Additional Information
The Mosquito helicopter's operators manual states that to fly the helicopter, potential pilots must receive proper training, and it recommends training to private pilot status in a small training helicopter. Training to student pilot status is considered the minimum acceptable amount. Operation by an inadequately trained pilot could result in severe injury or death. The manual also addresses the Height-Velocity curve: if the Mosquito is above approximately 10 feet, beyond which a hovering autorotation can be safely performed, it must be at a minimum of 250 feet before hovering is again permitted. In the event of an engine failure while hovering between 10 and 250 feet, the rotor blades would lack sufficient inertia to maintain rpm and insufficient time to build adequate forward speed for a normal autorotation.