History of Flight
On February 25, 2018, about 0810 eastern standard time, an Airborne Windsports Edge XT-912 trike, registered N98YW, was substantially damaged when it crashed near Eustis, Florida. The sport pilot was fatally injured. The weight-shift-control aircraft was operating under Title 14 Code of Federal Regulations Part 91 as a personal flight.
The pilot had recently purchased the aircraft and spent the day before assembling it. The accident flight was his first in the aircraft. He taxied the trike to runway 18 and performed three takeoffs and landings within the length of the runway, each time climbing to about 30 feet above ground level, landing, and taking off again. He then taxied back to the beginning of runway 18 and performed two more short takeoffs and landings. During a third takeoff, he continued to climb and joined the airport traffic pattern.
Witnesses observed the aircraft on the downwind leg, then turn onto and overshoot the base leg of the traffic pattern. It continued toward final approach, overshooting the extended centerline. The aircraft then made a hard left turn toward the final approach leg, and its wings began rocking up and down. The right wing "went down," the engine was heard accelerating, and the aircraft impacted the ground.
Personnel Information
According to Federal Aviation Administration records, the pilot held a sport pilot certificate with an endorsement for weight-shift-control land aircraft and a light sport aircraft repairman certificate. He was issued the sport pilot certificate on December 15, 2012. On the application, he reported 35 total hours of flight experience. His logbook was never recovered, and no other documentation of his flight experience was found.
Aircraft Information
The accident trike was a two-place, tandem-configured weight-shift-control aircraft with a framed pivoting wing and a fuselage controllable only in pitch and roll as the pilot changed the aircraft's center of gravity relative to the wing. Flight control depended on the wing's ability to deform flexibly, rather than on control surfaces.
Wreckage and Impact Information
Examination of the accident site by an FAA inspector revealed the trike impacted the ground on airport property north of the runway 18 threshold, right of the extended centerline, in a nose-low, right wing down attitude.
The trike base and wing displayed significant impact damage. The flight control bar separated from the left hand down tube but remained attached to the right. The main mast tube fractured 4 inches from its root attach point but remained attached via a leather and Velcro sleeve. The backup loop was found separated from its attach point. The hand throttle was in the idle position, and both ignition switches were in the "ON" position. The pilot's seat and fuel tank remained attached.
The left and right main landing gear wheels and hubs remained attached to their swing arms and compression struts. The nosewheel assembly separated from the trike base. The brake lever and throttle foot pedals remained attached. About 2 feet of throttle cable remained attached to the foot throttle lever; examination of the break revealed features consistent with tensile overload.
The Mylar and Dacron sail had no large tears and remained in one piece. Both leading edge tubes displayed extensive impact damage. Many aluminum battens from both wings displayed impact damage. The right wing D-tube airfoil strut separated from its attach point. The keel tube fractured 10 inches from its forward starting beam. The right wing leading edge tube remained attached to the nose plates. The right wing cross bar remained attached to its bracket. The right wing lift strut separated from its attach points. The wing trimmer handle was attached to the strut, and the trim cable remained attached. The swage on the trimmer wire indicated the trimmer setting was in the "INCREASE TRIM SPEED" range. A rear flying wire separated with evidence of tensile overload.
The left wing leading edge tube fractured 9 inches outboard of the center attach point. The outboard end of the left wing cross bar remained attached and displayed impact damage. The left wing lift strut separated into two pieces, fractured 3 feet from its upper attachment point. The left wing pivot sprog remained attached. The left wing down tube airfoil strut fractured 3 feet 9 inches from its center point attachment. The left wing front flying wire remained attached.
Examination of a sample from broken flying wires at the NTSB Materials Laboratory revealed no pre-existing crack propagation features, and corrosion present did not indicate fracture from corrosion.
On February 26, 2018, the airport manager reported that when moving the trike, they found the airspeed indicator stuck on 34 knots.
Propeller and Engine Examination: The propeller was fragmented from the hub. The engine air filters were crushed; the carburetor for cylinders 1 and 3 was displaced from the intake socket. No fuel return line was installed. Intake manifolds had coolant-filled aftermarket aluminum blocks for carburetor ice prevention. No fire sleeves on fuel lines. The oil tank lid top was in line with the oil pump bottom. The fuel shut-off was in the on position. Carburetor vent lines were routed correctly; fuel pump vent was unobstructed with no vent line attached.
Examination of the carburetor float bowl for cylinders 1 and 3 revealed no fuel and small amounts of contamination; a portion of material was missing from one float. The main fuel jet was unobstructed. For cylinders 2 and 4, small amounts of fuel with automotive gasoline odor were present, testing negative for water. Floats were in good condition.
The ignition system had no anomalies; spark plugs were in good condition with similar burn patterns. The No. 1 spark plug connection probe was bent from impact.
The engine drive train was rotated by hand; continuity and thumb compression were established for all cylinders. The drive train rotated smoothly with no unusual noises. The engine was subsequently test run at different power settings with no anomalies, and was shut down by cutting off air supply to carburetors.
Additional Information
For about 5.5 years before purchasing the accident aircraft, the pilot had flown a Krucker Manufacturing Tundra 582, a cable-braced weight-shift-control trike with a cruise speed of 47 knots and stall speed less than 26 knots. In contrast, the accident trike's arrow wing was a high aspect ratio, performance flex wing design with a quicker roll rate, using struts instead of bracing cables. Its cruise speed was 75 knots and stall speed 35 knots.
The Weight-Shift Control Aircraft Flying Handbook notes that a given angle of bank in a level turn produces the same load factor regardless of airspeed, and that additional load factor increases stalling speed significantly, as stalling speed increases with the square root of the load factor. For example, a light aircraft stalling at 40 knots in level flight stalls at nearly 57 knots in a 60° bank.
According to the Edge XT-912 Aircraft Operating Instructions, no untrained or unqualified person, or anyone unfamiliar with the wing and base combination, should attempt to pilot the aircraft unless under professional instruction.
Medical and Pathological Information
An autopsy by the State of Florida District 5 Medical Examiner determined the cause of death as multiple blunt force injuries. Toxicological testing by the FAA Forensic Sciences Laboratory was negative for ethanol and drugs of abuse.