What happened
On 30 August 2005, a Team Himax microlight, registration G-CCAJ, departed Rhigos Airfield in South Wales for a private flight. After taking off, the pilot began an abbreviated circuit. During the turn from the downwind leg onto the base leg, the aircraft experienced a wing drop and entered a steep nose-down attitude. The aircraft struck the ground within the airfield boundary at a high angle of descent, causing the aircraft to be destroyed. The pilot sustained serious injuries.
An observer on the ground witnessed the aircraft's descent and noted the sudden change in attitude before the aircraft disappeared from view. Following the impact, the pilot was assisted by a bystander and subsequently treated by an air ambulance.
The investigation
The AAIB examined the wreckage and recovered data from a GPS unit, which tracked the aircraft's path and ground speed. The investigation focused on the aircraft's flight path, the engine's condition, and the integrity of the cockpit restraint system.
Investigators found that the engine was functioning normally at the time of impact, with no evidence of mechanical failure or fuel starvation. However, the investigation revealed that the shoulder harness securing cable had failed. This cable, which was made of stainless steel rather than the specified galvanised carbon steel, had been routed through tight bends in the mounting bracket. The failure occurred at the points where the cable passed through the holes in the elevator control bracket, likely due to a combination of tensile load and the tight radius of the bends.
Findings
- The aircraft stalled during a right turn at the end of the downwind leg.
- The pilot was likely flying at a low level with a significant tailwind, which may have created an illusion of sufficient airspeed.
- The aircraft lacked a stall warning system, making it difficult to detect the onset of the stall in a low-inertia microlight.
- The shoulder harness attachment cable failed in shear due to the stress of being routed over sharp edges/tight radii.
- The harness cable was not installed in accordance with the original design drawings.