What happened
On 3 May 2013, a Short SC7 Skyvan 3, registration G-BEOL, was performing an aerial work flight when it experienced a landing gear failure upon touchdown at Weston-on-the-Green, Oxfordshire. The aircraft had previously refuelled at RAF Brize Norton and was returning to Weston-on-the-Green for a landing on the grass Runway 27.
During the landing sequence, the pilot was preparing to use the tiller for steering control when the nosewheel and its associated yoke assembly suddenly detached from the aircraft. This caused the aircraft to veer off the runway and come to a stop in a nose-down position. Following the incident, the pilot performed standard engine and shutdown procedures, and all zero injuries were reported as the crew and three passengers disembarked safely. The aircraft sustained damage to the underside of the fuselage and the nose landing gear assembly.
The investigation
The AAIB investigation focused on the mechanical failure of the nose landing gear. While the pilot initially described the landing as normal, he later noted that an unusual nose gear shimmy had been observed during the preceding landing at RAF Brize Norton, though it had not recurred during the taxi or takeoff for the return leg.
Technical examination of the nose landing gear assembly revealed that the gear had fractured across the plated portion of the oleo. Forensic analysis of the components showed that the lower portion of the torque link had separated at the mid-pivot point. Furthermore, two distinct fracture faces were identified: one on the main forging and the yoke, and a second around the circumference of the outer oleo piston where the attachment thread terminates. The investigation also noted a fracture in the inner oleo liner near the area where the diameter increases to accommodate the piston thread.
Findings
- The nose landing gear fractured at the plated portion of the oleo, causing the nosewheel and yoke assembly to detach.
- The pilot had observed unusual nose gear shimmy during the previous landing at RAF Brize Norton.
- The primary cause of the failure involved fractures within the nose landing gear assembly, specifically involving the torque link, the main forging, and the oleo piston/liner.
- A forensic examination of the damaged components was being conducted by the manufacturer to determine the exact mechanism of the fractures.