Accident Overview
On April 20, 2018, at 1830 eastern daylight time, an experimental amateur-built Kolb Mark III, registration N9123R, was destroyed when it collided with terrain shortly after takeoff from Collegedale Municipal Airport (FGU) in Collegedale, Tennessee. The private pilot, who was the sole occupant, sustained fatal injuries. Visual meteorological conditions prevailed near the accident site, and no flight plan was filed for the local personal flight conducted under 14 CFR Part 91.
Witness Accounts
The airplane's owner reported that the pilot was intended to perform high-speed taxi testing. The pilot completed two high-speed taxis and "crow-hops," during which he would lift off to about 10 feet above ground level and then land. During the third taxi, the owner heard the pilot apply full power, and the airplane took off, turned right above trees adjacent to the runway, and entered the traffic pattern. The airplane then leveled, banked left, and dove into the ground. The owner noted that the pilot did not appear to attempt to correct the dive.
Another witness, located near the northeast end of the runway, observed the airplane about 500 feet above ground level above the departure end of the runway. The witness stated that the airplane turned left and dove straight into the side of a hill. The witness reported that the engine sound diminished before the turn but increased during the descent, with the engine "screaming" as the airplane descended to impact.
Video Evidence
The owner provided a video recording that captured the ground taxi and takeoff but ended before the descent. The video showed a takeoff roll of about 400 feet. The engine sound was smooth and continuous throughout the takeoff roll and the 45 seconds of climb recorded. After takeoff, the airplane exhibited a high angle of attack and steep climb, with the tops of both wings visible. The airplane drifted right of the runway centerline but remained flat in the roll axis.
Pilot Information
The pilot held a private pilot certificate with airplane single-engine land and instrument airplane ratings. His most recent FAA second-class medical certificate was issued on November 1, 1999, at which time he reported 71 total hours of flight experience. A review of the pilot's logbook photographs indicated he had accrued about 248 total hours, but the quality of the photographs prevented determination of total, type, and recency of flight experience. The most recent entries and endorsements showed flights on July 9, 2016, in a tail-wheel equipped ultralight and on September 10, 2016, in an unidentified aircraft.
Aircraft Information
The airplane was manufactured in 1995 and registered to the owner on January 4, 2017. It was powered by a Suzuki 1.3-liter, 4-cylinder automobile engine. The owner purchased the airplane disassembled and "half restored" from what appeared to be accident damage. The owner and pilot completed repairs and assembly using a build manual and plans. No airframe or engine logbooks were available, and a condition inspection had not been completed. The owner stated that the condition inspection was supposed to be completed before the first flight.
Medical and Toxicological Findings
The Office of the Hamilton County Medical Examiner performed an autopsy and determined the cause of death as multiple blunt force injuries. Toxicological testing detected the presence of cetirizine, a sedating over-the-counter antihistamine, in blood and liver samples. According to the NTSB Medical Officer, the levels were below the therapeutic range and, assuming normal dosage at ingestion, suggested the pilot was within the FAA's recommended period for airman duties.
Weather and Wreckage
At 1853, weather conditions at Chattanooga Lovell Field, 9 miles from the accident site, included few clouds at 25,000 feet, 10 miles visibility, wind from 010° at 10 knots, temperature 20°C, dewpoint -4°C, and altimeter setting of 30.28 inches of mercury.
Examination of wreckage photographs showed the airplane came to rest uphill of the initial ground scar, with the wreckage path oriented along a magnetic heading of about 300°. Impressions in the grass on either side of the scar matched the dimensions of each wing's leading edge and span. Both wings were uniformly crushed aft in compression, with shredded fabric covering. The empennage remained largely intact. Control continuity could not be established due to extensive damage and entanglement of structure and control cables. Fractures and breaks in cables and bellcranks were consistent with overload failure. The cockpit area was destroyed, the instrument panel separated, and the engine cradle was attached only by wires and cables. A nylon cargo strap, used to secure sand bags and a board for ballast, was found entangled in the wreckage.
Manufacturer and Advisory Guidance
The Kolb Aircraft website states: "Although Kolb aircraft are easy to fly and have gentle flight characteristics, they are also high-performance aircraft. We recommend training or some transition training before attempting flight in our aircraft." FAA Advisory Circular 90-89B, "Amateur-Built Aircraft and Ultralight Flight Testing Handbook," emphasizes that test flying is a critical undertaking requiring thorough planning, skill, and common sense. It provides guidelines for test pilot experience, recommending a minimum of 100 solo flights in similar ultralights and adherence to a flight test plan. The owner reported being unfamiliar with this advisory circular.