What happened
On 17 May 2023, a Quik GT450 microlight, registration G-CEVW, was performing a private flight from Lundy Island back to Park Hall Farm Airfield. Shortly after departing Lundy Island at 1215 hrs, the pilot experienced a sudden and significant pitch-up tendency accompanied by a reduction in airspeed. The pilot found the control forces to be extremely heavy, noting that he had to wedge the control bar under his arms to maintain control of the aircraft.
Unable to maintain a stable flight path, the pilot decided to return to Lundy Island. During the approach to runway 24, the aircraft's response remained sluggish and the control loads remained extreme. The pilot attempted to manage the approach despite being poorly aligned with the runway, fearing that a go-around would be impossible due to the physical strength required to manipulate the controls. The aircraft made a heavy touchdown, resulting in extensive damage to the wing and airframe, and the collapse of the nose landing gear. The pilot sustained minor injuries and was able to exit the aircraft without assistance.
The investigation
The AAIB examined the wreckage at a storage facility and found that the wing structure had been severely deformed and the sail material ripped. Investigation of the wing keel revealed that the roll bearing had migrated approximately 300 mm rearward along the keel tube. This movement had caused the bearing to strike the trim attachment bracket, leaving visible witness marks.
The investigators determined that the M6 caphead bolt and its associated Nylok nut, which were responsible for securing the roll bearing in place, were missing. The loss of this single bolt allowed the hang bracket and roll bearing to slide aft, which shifted the aircraft's center of gravity and induced the severe nose-up pitch that the pilot encountered.