What happened
On 2 September 2002, a Tri R-Kis, registration G-OKMA, was completing a private flight from Shoreham to Coventry Airport. During the landing on Runway 05, the pilot performed a power-off approach, touching down on the main wheels while keeping the nosewheel elevated. While the main wheels remained in contact with the runway, the nosewheel briefly lifted and then made contact with the surface. Shortly after, the nose of the aircraft began to drop, causing the propeller to strike the runway and break apart.
Following the impact, the aircraft slid along the runway on its nose. The pilot reported that the engine and fuel supply were shut down during the sequence, and the electrical master switch was deactivated before the crew and passenger evacuated the aircraft. There were no fatalities and no injuries to the two occupants.
The investigation
Investigators examined the runway surface, which showed evidence of the nosewheel separating shortly after touchdown. The sequence of impact was marked by propeller strikes, followed by a 40-centimetre gouge in the runway caused by the noseleg, and a 150-metre track created by the lower engine cowling.
Technical analysis focused on the steel noseleg, which had fractured at both its upper and lower ends. The upper fracture occurred near a welded lateral tube and was found to be entirely ductile, though microscopic examination revealed evidence of weld porosity. The lower fracture was located just below the 45-degree welded joint. While the majority of this fracture was ductile, a longitudinal section contained corrosion staining that had penetrated half of the wall thickness. This staining indicated the presence of a pre-existing crack.
Findings
- The investigation established that the lower fracture of the noseleg occurred first.
- This initial failure caused the nosewheel to lose its structural integrity, allowing the nose to drop and strike the runway.
- The resulting high bending moment applied to the leg led to the secondary ductile failure at the upper end.
- A pre-existing crack was present at the lower section of the leg, which may have been inadvertently created during the manufacturing process when the lower attachment tube was being formed into an oval shape.