On June 5, 2020, about 1925 eastern daylight time, an experimental, amateur-built Challenger II airplane, N850RW, was substantially damaged when it was involved in an accident near Wurtsboro-Sullivan County Airport (N82), Wurtsboro, New York. The pilot and student pilot were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 test flight.
According to a witness, the airplane was tail heavy, therefore the pilot/owner and student pilot had added ballast to the front of the airplane and performed several high-speed taxi runs prior to departing N82 for a test flight. After liftoff, the airplane began to yaw to the left and continued to yaw left toward a ridgeline. The airplane did not climb and remained just above the treetops. It then sounded to the witness as though the pilot pulled back the power before the witness lost sight of it over the trees and heard the impact.
Inspection of the accident site by a Federal Aviation Administration (FAA) inspector revealed the airplane descended nose first into the trees, came to rest mostly intact, and inverted in a wooded area about 1,420 ft and 143° from the airport center. All major structural components of the airplane were located within a debris field limited to the size of the airplane. Both wings were substantially damaged, and the right wing was mostly impact separated at the wing root. The empennage remained mostly undamaged. There was a faint smell of fuel at the accident site.
The airplane, engine, and engine accessories were examined under the supervision of an FAA inspector after recovery to N82. Both cylinder carburetor float bowls and the primer bulb in the fuel line between the fuel tank and carburetor contained fuel and the fuel was absent of water and debris. All spark plug leads were firmly attached at both ends except for the aft spark plug in cylinder No. 2, which was impact damaged. The spark plugs were removed and visually examined with no anomalies noted. The propeller was rotated by hand, and thumb compression and suction were noted on both cylinders. No anomalies were noted with the engine. Examination of the propeller blades revealed that one of the blades was fractured about 8 inches from the propeller hub and exhibited some leading edge damage near the blade tip. No chordwise scratching was evident on either blade.
Control continuity was established through the rudder cables at all points; however, the rudder pedals were not movable. Three canvas bags of sand ballast were found in the forward section of the airplane: one to each side of the rudder pedals and one forward of the rudder pedals on the tube that braced the nose wheel. The bag on the right side had a small tear and contained 18 lbs of sand, and small amounts of sand were nearby. The bag on the left side was wrapped around the bottom of the left rudder pedal, significantly torn, and weighed 5 lbs. There was a small amount of sand nearby. The center bag was mostly intact and weighed 22 lbs. It was the inspector’s opinion that given the size of the ballast bags that all had been about equal weight prior to the accident flight.
According to FAA records, the two-seat airplane was issued a Special Airworthiness Certificate on November 22, 2019. The airplane was powered by a rear facing Rotax 503ULDCDI, two-cylinder, 50 hp engine, that was mounted aft of the wings, behind the main cabin, that drove a Warp drive two-bladed propeller. Examination of the logbooks revealed that the airplane had not yet completed the 40 hours of phase 1 flight testing required by its Special Airworthiness Certification.
Weight and balance calculations were performed using weight and balance documents located in the logbook, fuel estimated at half tank, or 5 gallons, the pilot’s weight at his most recent FAA physical, the student pilot’s autopsy weight, and 66 pounds of ballast. Calculations revealed that the airplane weight was about 927 lbs at takeoff, with a center of gravity 82.86 inches aft of datum. According to documentation provided by the manufacturer, the airplane's maximum allowable gross takeoff weight was 800 lbs with a center of gravity range at takeoff of 80 to 90 inches aft of datum.
The Quad City Ultralight Aircraft Corp. "Challenger Owner's Manual" included the following information:
"…If the nose wheel will not remain in contact with the ground, ballast must be added until it does. Solo flight is restricted to front seat. (On two seat Challengers with the heavier "503" engine, electric start and 10 gal. tank, ballast may have to [be] added to the nose for pilots under 160 lbs.)"