Accident Overview
On July 6, 2019, at 1045 central daylight time, an experimental amateur-built Freeman Super Koala, registration N220FF, made a hard landing during a return to Mercer County Regional Airport (HZE) in Hazen, North Dakota. The accident followed a loss of aileron control. The commercial pilot, who was the sole occupant, was uninjured. The airplane, owned and operated by the pilot under 14 CFR Part 91 as a maintenance test flight, was substantially damaged. Day visual meteorological conditions prevailed, and the flight had originated from HZE without a flight plan.
Pilot Report
According to the pilot, the aircraft had recently undergone reassembly of its wings and flight control rigging. The accident occurred during the fourth test flight. The pilot reported that the ailerons were not fully functional in flight, and he and the airplane owner were attempting to diagnose the problem. After a preflight inspection, taxi, and run-up, the controls were confirmed free and correct. During takeoff from runway 14, the airplane became airborne quickly. At about 15 feet above ground, it began rolling to the left. Despite applying full right aileron, the roll continued, and the airplane descended, striking the ground in a left-wing-low attitude approximately 10 to 20 feet from the runway. The left wing spar, bottom fuselage, cowling, engine, landing gear, and firewall were substantially damaged.
Investigation Findings
A Federal Aviation Administration (FAA) inspector from the Fargo Flight Standards District Office reported that the airplane had been purchased by the current owner from an estate, disassembled, and transported to Hazen. The owner and an FAA-certificated mechanic assembled the aircraft. They encountered difficulties with aileron cable tensions and were unable to obtain necessary information from the kit manufacturer. After several adjustment attempts, they determined that test flights were required. A post-accident inspection revealed improper rigging of the ailerons and improper cable tensions. Additionally, the airplane's maintenance logbook indicated that it had not been properly signed off for return to service after maintenance.