What happened
On 16 September 2003, an Avid Flyer, registration G-BTKG, was performing a private cross-country flight. While returning to the farm strip at Drayton St Leonard, Oxfordshire, the pilot initiated an approach to Runway 24. The weather was clear with calm winds and good visibility.
Upon crossing the airfield boundary, the pilot reduced the throttle to perform a glide landing. The aircraft's first touchdown resulted in a bounce. During the subsequent second touchdown, the nose landing gear leg collapsed and the nosewheel became detached from the aircraft. The aircraft stopped a short distance from the point of impact. There were no injuries to the pilot, though the engine cowling and nose landing gear sustained damage.
The investigation
Investigators examined the broken nose landing gear leg, which had previously undergone a modification to include an internal reinforcement sleeve. An inspection by a PFA inspector revealed that the leg tube and the sleeve had been subject to progressive stress cracking for a period leading up to the failure.
It was determined that the cracks originated near a hole on the leading face of the leg. This hole had been drilled to facilitate installation on a different aircraft. When the component was later installed on G-BTKG, a second hole was drilled at a 90-degree angle to the first, leaving the original hole redundant. This configuration created a significant stress concentration point.
Additionally, the investigation noted that the pilot had experienced wheel shimmy during recent flights, which had been attributed to tyre pressure rather than structural issues.