What happened
On 8 September 2007, a Denney Kitfox Mk2, registration G-KAWA, was conducting a local flight near Wing, Aylesbury, to evaluate its handling characteristics ahead of a permit renewal. During the flight, the pilot performed various maneuvers, including stalls and assessments of flight performance with and without flaps.
While approaching Runway 33, the pilot executed an uneventful go-around. To land on Runway 29, a specific left-hand turn was required. During the final approach at approximately 60 mph, the pilot noted that the ailerons felt "mushy." As the aircraft entered the flare, it began rolling to the left. Although the pilot used the rudder to level the wings, the aircraft began crabbing toward hay bales located on the left side of the runway. The pilot applied full power in an attempt to climb away, but the aircraft failed to gain altitude. The left wing subsequently struck a bale, causing the aircraft to yaw violently and slide across the runway intersection, eventually coming to a halt. The pilot, who was the sole occupant, sustained minor injuries.
The investigation
The investigation focused on the flight controls and the mechanical state of the aircraft. Upon inspection, a broken ball-link rod-end connector was discovered in the aileron circuit at the base of the control column. The pilot noted that the ailerons had felt jammed in an up/right down position during the incident, which he believed explained the roll.
Technical analysis of the broken component revealed that the fracture occurred through the threaded section of the fitting, near the backing nut. The examination showed evidence of gross plastic deformation and a fracture surface characteristic of a compression overload. There was no evidence of fatigue or progressive failure, and the component was not in a weakened state prior to the accident.