N63917Worthington Donald Wayne SONERAI II LT · 1999

On March 29, 2014, about 1440 mountain daylight time, a Worthington Sonerai 11L experimental airplane, N63917, crashed near Highlands Ranch, Colorado. The private pilot was fatally injured and the airplane was destroyed. The airplane was registered to and operated by a private individual as a 14 Code of Federal Regulations Part 91 flight. Visual meteorological conditions prevailed for the local flight, which was not operated on a flight plan.

The pilot purchased the airplane in November, 2013. The pilot's first flight in the airplane occurred the morning of the accident. The pilot told a family member that the first flight had terminated early due to a leak in the fuel sight gauge. The pilot made a repair to the airplane and took off for a second flight. Witnesses reported seeing the airplane "struggling to stay airborne," and that the engine was running roughly as the airplane approached an open field. The airplane was observed to cross over a set of power lines, roll to the left, and descend into the ground. A post-impact fire ensued.

Clear tubing and materials suitable for replacing the fuel sight gauge were located in the pilot's hanger. A cracked section of tubing consistent with the fuel sight gauge was recovered from a garbage can in the hanger.

The pilot, age 60, held a private pilot certificate with ratings for airplane single-engine land. His last Federal Aviation Administration (FAA) Third-class medical certificate was issued on April 19, 2006, with no limitations.

An examination of the pilot's flight records indicated 573 total flight hours, with no hours in the accident model airplane. The flight records indicated a break in flying between September 19, 2003, and January 1, 2014. The pilot did not log any additional flight time following a single 1.2 hour flight on January 1, 2014, and the day of the accident.

The 1999-model airplane, serial number 00024, was a low wing, fabric and metal covered airplane, with a fixed tricycle landing gear, and was configured for two occupants. The airplane was powered by a direct drive, horizontally opposed, carbureted, air-cooled, four-cylinder engine. The engine was a Volkswagen Aero Vee rated at 75 horsepower, and was driving a two-bladed constant pitch wooden propeller. The last inspections on the airframe and engine were each conditional type inspections on November 1, 2013.

Weather at APA at 1453 was reported as wind 330 degrees at six knots, 10 miles visibility, few clouds at 17,000 feet, a broken ceiling at 25,000 feet, and altimeter 29.97.

The 1999-model airplane, serial number 00024, was a low wing, fabric and metal covered airplane, with a fixed tricycle landing gear, and was configured for two occupants. The airplane was powered by a direct drive, horizontally opposed, carbureted, air-cooled, four-cylinder engine. The engine was a Volkswagen Aero Vee rated at 75 horsepower, and was driving a two-bladed constant pitch wooden propeller. The last inspections on the airframe and engine were each conditional type inspections on November 1, 2013.

The airplane impacted an open field eight miles west of APA on a heading of 033 degrees. The airplane traveled approximately 50 feet from the initial impact point before coming to rest upright. The initial impact point consisted of a scrape mark where the left wing impacted and a shallow crater where the engine impacted. Fragments of the majority of the propeller were located at the engine impact point, or in the immediate area.

The airplane fuselage was constructed primarily of metal tubing covered by fabric material. Fire consumed the fuselage covering from the engine cowling area aft to just forward of the horizontal stabilizer. The wings were manufactured of aluminum spars and ribs covered by a metal skin. Fire consumed the center sections of the wings that were connected to the fuselage, and outboard of the fuselage about one to two feet on each side of the fuselage.

Flight control continuity was continuous from all control surfaces to their respective controls in the cockpit.

An engine examination on scene revealed both propeller blades were broken off and splintered about eight to ten inches from the propeller hub. The propeller spinner exhibited crushing deformation to about two-thirds of its surface, with little to no rotational scoring or rotational deformation evident. The left and right cylinder head covers were separated, exposing the rocker arms for each cylinder. The propeller was rotated by hand and all rocker arms exhibited movement.

The airplane was equipped with a 10 gallon aluminum fuel cell mounted aft of the engine firewall, and forward of the instrument panel. The fuel system included a sight gauge to monitor fuel available. The sight gauge consisted of a transparent rubber hose that was mounted vertically on the forward instrument panel so as to be visible during flight. About two-thirds of the fuel tank was consumed by fire. The sight gauge was not located in the wreckage.

Fuel was gravity fed directly from the fuel tank to an Aerocarb slide style carburetor mounted on the engine. The carburetor was impact and fire damaged. Functional testing of the carburetor could not be accomplished due to the damage. The portion of the fuel feed lines from the finger strainer mounted in the tank to the gas valve was located. The portions of the fuel system that were located exhibited impact and fire damage. The remainder of the fuel system was not located due to fire and impact damage.

No anomalies were noted with the available wreckage and the engine that would have precluded normal operation prior to impact.

The Douglas County coroner, located in Castle Rock, Colorado, performed an autopsy on the pilot on March 30, 2014. The cause of death was attributed to multiple blunt force injuries.

The FAA, Toxicology Accident Research Laboratory, located in , conducted toxicological testing on the pilot. Testing for carbon monoxide and cyanide were negative. No volatiles or drugs were detected.