What happened
On 25 June 2000, an Evans VP-2, registration G-BUGI, was performing a private flight at Cardiff Airport, Wales. The pilot, returning to the aircraft for his first flight of the season, approached Runway 30 under light northerly wind conditions. During the landing sequence, the aircraft touched down on its main wheels rather than in a full three-point position.
As the aircraft decelerated, it began to veer toward the left. Although the pilot attempted to correct the directional swing, the aircraft drifted approximately 30 to 40 degrees off the runway centerline. During this maneuver, the right wing began to drop, and the aircraft eventually came to a halt with the right wing tip touching the runway surface. There were no injuries to the pilot, though the aircraft sustained damage to the right main landing gear and the underside.
The investigation
Investigators examined the right main landing gear and discovered that the leg had folded, leaving the wheel in a nearly horizontal position. During the recovery process, it was noted that the leg could be straightened with very little force, leading to concerns regarding the structural integrity of the component. Significant surface corrosion was also observed on the leg, which flaked away during the distortion.
The landing gear assembly consisted of a single, thick, formed aluminium alloy member reinforced with diagonal bracing wires. While these wires were designed to manage vertical landing loads, the assembly lacked bracing to resist side loading, such as that produced by a ground loop or uncorrected drift.
A metallurgical analysis of a sample from the leg revealed severe exfoliation corrosion on the upper surface. However, this corrosion affected only a small portion of the cross-section and was not deemed a primary cause of the loss of bulk strength. Hardness testing of the alloy returned normal results for heat-treated aluminium.
Findings
- The aircraft's right main landing gear collapsed during a period of directional instability.
- The pilot's delayed response to a leftward swing contributed to the excursion.
- The left brake exhibited a tendency to bind, which may have assisted the development of the swing.
- The landing gear structure was unbraced against side loading forces.
- The landing gear component had been stored for ten years prior to being installed on the aircraft.