Ridgely, MD, USA
N402HA
MOYES DRAGONFLY
The flight instructor who was towed aloft by the tow airplane with his student in a tandem hang glider reported that the airplane did not lift off until it was near the end of the grass runway. A witness reported that, after the airplane released the glider, it began to turn left while climbing until it completed a 270-degree turn, reached a peak altitude of about 270 feet above ground level, then entered a spin, rotated one to two times, and subsequently impacted the ground. Postaccident examination of the engine revealed no evidence of any preimpact failures or malfunctions that would have precluded normal operation. Further, no evidence was found indicating that a flight control malfunction occurred or that the tow rope became entangled. During examinations, one of the airplane's bracing cables, which strengthened and stiffened the airplane's structure and normally extended from the upper surface of the right wing to a plate above the tailwheel, was found on the ground beneath the right wing with both of its ends broken from the airplane structure attachment points. The cable had fractured in overload in the eye splice sleeves at both ends. Although failure of this cable might have distorted the airplane's structure in flight and resulted in controllability challenges, it could not be determined if the cable failed in flight or during the impact sequence. It is also possible that the pilot became distracted during the climb while watching the hang glider after the release and allowed the airspeed to degrade, which resulted in an aerodynamic stall and subsequent spin.
HISTORY OF FLIGHT On July 23, 2011, about 0715 eastern daylight time, a Moyes Dragonfly airplane, N402HA, owned and operated by Highland Aerosports Inc., was substantially damaged when it impacted terrain at Ridgely Airpark (RJD), Ridgely, Maryland. The pilot was fatally injured. Visual meteorological conditions prevailed for the Title 14 Code of Federal Regulations (CFR) Part 91 glider tow flight. According to a flight instructor who was towed aloft by the airplane with his student in a tandem configured hang glider, it was "hot and sticky" that morning and he had briefed his student prior to the flight that it would take a longer ground roll than normal to takeoff. After they took off in tow, the flight instructor climbed the hang glider up to an altitude of about 15 feet above ground level (agl) behind the airplane. During the tow he observed that the airplane did not lift off until it was near the end of the grass runway. As the airplane reached the end of the runway, he saw the towline "release" from the airplane. He also observed that as the airplane reached an adjacent soybean field, that the airplane was "tickling the beans with its wheels". The flight instructor then continued straight ahead and executed a landing to that same soybean field. Then as he and his student were getting out of their harnesses, he heard the airplane above him. It was "really loud" and he wondered what the pilot was doing. Moments later he heard the airplane impact the ground behind him. According to a witness, after the release, the airplane began to turn left while climbing until it had completed a 270 degree turn, and reached a peak altitude of approximately 200 feet agl. It then "dropped into a spin". He could hear the engine running, and he observed the airplane then do one, to two rotations, before it impacted the ground in an approximate 45 degree nose down attitude PERSONNEL INFORMATION According to Federal Aviation Administration (FAA) records, the pilot held a commercial pilot certificate with ratings for airplane single-engine land and instrument airplane. She also held a private pilot certificate with a rating for gliders. Her most recent application for a FAA first-class medical certificate was dated October 14, 2008. According to pilot and company records, the pilot had accrued 400.8 total hours of flight experience, during which she had accomplished approximately 425 tows, and had accrued 92.3 hours in the airplane make and model. AIRCRAFT INFORMATION The accident aircraft was a high wing, strut and cable braced, open cockpit, tailwheel equipped airplane. It was constructed of bolted 6061-T6 aluminum and had a single seat mounted on a fuselage boom tube that ran from the rudder pedals to the tail. It was powered by a 115 horsepower, Rotax 914ULS engine, mounted in a pusher configuration above the boom tube, level with the trailing edge of the wing, driving a fixed pitch, Kiev, 5-blade, composite propeller which rotated counterclockwise when viewed from the rear of the airplane. It was equipped with conventional landing gear with the two main wheels being mounted on chrome molybdenum steel gear legs and axles which were mounted to the fuselage boom tube, and a steerable tail wheel mounted on the aft lower end of the boom tube. The wing and tail surfaces were both covered in pre-sewn Dacron envelopes. The wing was supported by "V" and Jury Struts. The fuselage boom tube, empennage, and extended rudder post (which was used as an attachment point for towing of aircraft), were supported by steel cables attached to the wings. The horizontal stabilizer was mounted at 13 degrees angle of incidence negative to the wing to maintain pitch stability, balancing lift, from the flaperons. Downforce on the horizontal stabilizers would be transmitted to the wings via the steel cables which ran from the upper surface of the wings to plates on the each side of the boom, just above the tail wheel. The slack in these cables would be taken out when the airplane would lift off and the boom would normally be straight when the Dragonfly was in flight. According to FAA and maintenance records, the airplane was manufactured in 2004. The airplane's most recent annual inspection was completed on May 24, 2011, approximately two months prior to the accident. At the time of the inspection, the airplane had accrued 1,569 total hours of operation. METEOROLOGICAL INFORMATION The reported weather at Easton/Newnam Field Airport (ESN), Easton Maryland, located 14 nautical miles southwest of the accident site, at 0653, included: calm winds, 6 miles visibility in mist, scattered clouds at 25,000 feet, temperature 28 degrees C, dew point 27 degrees C, and an altimeter setting of 29.98 inches of mercury. AIRPORT INFORMATION Ridgley Airpark was uncontrolled and field elevation was 64 feet above mean sea level (msl). It had one runway, 12/30. The runway was asphalt, in fair condition. The total length was 3,214 feet long and 50 feet wide. Hang glider and tow operations occurred on the grass adjacent to the south side of the runway. Examination of the grass adjacent to the runway where the accident airplane took off from revealed that it paralleled runway 12/30 and was oriented on a 121/301 degree magnetic heading. It was approximately 2,250 feet long, and varied between 50 to 75 feet wide. Its southeast end ended at a taxiway and its northwest end ended at the soybean field. Density altitude at the airpark at the time of the accident was approximately 1,575 feet msl. FLIGHT RECORDERS The airplane was not equipped with a flight recorder nor was it required to be under the CFRs. It was however equipped with a FLYTEC 4005 Variometer, which would automatically record the 20 most recent flights, including peak values of altitude, lift and sink, and flight duration. Examination of data revealed that a total of 5 minutes, 11 seconds of data from multiple flights had been recorded. Further examination revealed that on the accident flight the airplane had reached a peak relative altitude of 262 feet. WRECKAGE AND IMPACT INFORMATION Examination of the accident site revealed that the airplane had come to rest on an approximate 064 degree magnetic heading with the aft portion of the fuselage tube boom and empennage oriented on a 172 degree magnetic heading. The tow rope was discovered to have come to rest in two pieces with one portion located in front of the left wing, and the second and largest portion located in front of the right wing, where it was discovered to be laying on the ground in a "C" shaped arc with the open side of the "C" and ends, pointed roughly towards the front of the airplane, with the center (top) of the arc located approximately 150 feet from the front of the airplane. No evidence of the tow rope becoming entangled in vegetation or coming into contact with an object was discovered. Pieces from four of the propeller blades were located at the site, with the farthest piece (a propeller tip) being discovered 43 feet northeast of the main wreckage. Examination of the pieces revealed that two of them displayed transfer marks which matched the color of the airplane's wing. Examination of the portion of the 5-bladed propeller that still remained attached to the engine revealed that: - One blade was relatively intact but, it displayed two creases which extended from the leading edge to the trailing edge. - The second blade was fractured approximately 10 inches out from the propeller hub. The fracture extended outward towards the trailing edge, with the angle between the fracture and the leading edge at a 115 degree angle. - The third blade, was missing a portion of its tip, and displayed two creases extending from the leading edge to the trailing edge, with the inner crease located approximately 11inches from the center of the propeller hub which extending circumferentially to the trailing edge. The second crease was located approximately 16 inches from the center of the propeller hub and extended outwards towards the trailing edge, with the angle between it and the inner leading edge measured at approximately 115-degrees. - The fourth blade was fractured with the fracture initiating approximately 13-inches from the hub, and extending outward to the trailing edge with the angle between the fracture and the leading edge at an approximate125-degree angle. - The fifth blade was fractured with the fracture initiating approximately 13-inches from the hub. The fracture extended outward towards the trailing edge with the angle between the fracture and the leading edge measured at approximately 110-degrees. Engine Examination Examination of the engine revealed no evidence of any preimpact failures or malfunctions. When the propeller was rotated by hand the drive train exhibited no evidence of binding, and continuity was established from the propeller to the back of the engine. Thumb compression was established on all cylinders. The spark plugs appeared normal and were light gray in color. Oil was present in the rocker boxes and galleries of the engine. The turbocharger compressor, and turbine were interconnected, could be rotated by hand, and the inside of the housing revealed evidence of rotational scoring. Flight Control Examination Examination of the flight control system revealed no evidence of any preimpact failures or malfunctions which would have affected normal operation of the flight controls. All flight control pivot points were intact and, and control continuity was established from the ailerons, elevators, and rudder, to the control stick and rudder pedals. Airframe Examination Examination of the wing structure revealed that it was twisted spanwise; it displayed multiple areas of crush and compression damage, multiple twisted and broken structural tubes, and multiple tears in the Dacron wing envelopes. Some of which, along with indentations in a portion of an aileron torsion tube, were discovered adjacent to the remaining portions of the propeller blades and hub. Examination of the fuselage structure revealed multiple areas of crush and compression damage as well as numerous bent and broken tubes in the cockpit area. The boom tube was also fractured approximately two feet aft of the bulkhead assembly, but the horizontal stabilizer, elevators, vertical stabilizer, and rudder had remained attached to their mounts. Examination of the steel cables which strengthened and stiffened the airplane's structure (wire bracing) revealed multiple broken cables that exhibited evidence of tensile overload. One cable however, was found on the ground, beneath the right wing and it was discovered that neither end was attached to the airplane structure. Examination of the detached cable revealed that it was the cable which should have ran from a bracket on the upper surface of the right wing to a plate on the right side of the boom, just above the tail wheel which according to the Australian manufacturer served two purposes. The first was to provide a physical barrier for personnel moving close to the propeller while the engine is running and the second was to provide extra airframe rigidity. The cable was of "7 x 7" construction (7 strands each with 7 wires) with a clear plastic coating. Further examination revealed that it had fractured in overload in the eye splice sleeves at both ends. The cable was kinked near one of the fractured ends, and the center of the kinked portion displayed two holes consistent with localized overheating such as friction, with the coating on both sides of the holes displayed abrasion and distinctive scratches. Wires from the cable's core strand had been extruded between the outer strands on both sides of the holes. Examination of the eye splices on the cables also revealed that they displayed wear on their thimbles which, in one case (the thimble that was located next to the failed cable on the upper surface of the right wing), had worn through to its cable. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot by the Office of the Chief Medical Examiner, State of Maryland. Cause of death was multiple injuries. Toxicological testing of the pilot was conducted at the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The specimens were negative for carbon monoxide, cyanide, basic, acidic, and neutral drugs with the exception of Atropine, which is an anticholinergic and antispasmodic alkaloid that was administered by medical personnel post accident. SURVIVAL FACTORS INFORMATION The airplane was equipped with a Ballistic Recovery System (BRS) which FAA tests have shown that after activation, full parachute inflation could occur at altitudes as low as 260-290 feet above ground level. Examination of the wreckage revealed however, no evidence of the pilot attempting to activate the BRS. TESTS AND RESEARCH Aircraft Performance A review the manufacturer's documentation revealed that performance information was only published for airplanes equipped with a normally aspirated 64 horsepower Rotax 582 and that it was minimal in nature. According to the Australian manufacturer, airplanes equipped with the Rotax 912 or 914 engines would have slightly better performance .The airplane was capable of lifting off in ground effect at approximately 30 miles per hour (mph) in 213 to 361 feet depending on weight, and could clear a 50 foot obstacle at gross weight in 950 feet. When towing, the airplane would climb out at 200 to 400 feet per minute at approximately 35 MPH. When not towing, climb rate could exceed 1400 feet per minute. According to the flight instructor and the student they had anticipated a longer takeoff roll than normal due to the high ambient temperature. Review of their statements did not reveal however any evidence of any performance anomalies during the takeoff and the glider became airborne as expected which was indicative of normal thrust being produce by the airplanes turbocharged engine which could produce rated take off performance up to 8000 feet above mean sea level. Examination of Exemplar Dragonfly During a post-accident follow up visit to the operator's facility, the findings which were discovered during the examination of the cables from N402HA, were compared with the cables and eye splices on the operator's other Dragonfly, N401HA, which had been manufactured in 1999, and had accumulated approximately 2,400 total hours of operation. The examination of N401HA revealed that amounts of slack in the cables differed, the thimbles also displayed wear similar to that which was found on the accident airplane, and that slotted bushings in some of the eye splices prevented inspection of the connections. Photographs of the examinations from both aircraft were forwarded to the manufacturer who advised the NTSB that he had not seen wear to this extent on the Australian fleet or seen a tang cut into a thimble as much as this one and he could not explain the wear in the tang and thimble. The manufacturers indicated that the subject cables appeared to be other than original equipment manufacturer (OEM) parts. He also advised that the cable which broke on the accident airplane broke where they would normally break, at the NICO Press fittings (eye splice sleeves). ORGANIZATIONAL AND MANAGEMENT INFORMATION Highland Aerosports Inc. was owned and managed by two individuals and was located at RJD. They provided tandem hang gliding instruction and air tows. They also sold and serviced hang gliding equipment. Both owners held numerous United States Hang Glider Association certificates including Aerotow Administrator ratings. They also held United States Ultralight Association Basic Flight Instructor ratings. Additionally, they both held FAA Repairman Light Sport Aircraft certificates, they were maintaining, repairing, as well as performing the 100 hour and annual inspections on N401HA and N402HA under the auspices of their certificates.
An in-flight loss of control for reasons that could not be determined during postaccident examinations.
Source: NTSB Aviation Accident Database
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