What happened
On 8 July 2003, a Skyranger 912(1), registration G-CBWL, was involved in a serious accident at Barton Airfield, Manchester. The aircraft, a two-seat microlight, was being prepared for a local sightseeing flight. The pilot had arrived at the airfield and proceeded to rig the aircraft from its transport trailer, a routine process for this type of aircraft. During the assembly, the pilot was interrupted twice, once while connecting the flight controls and again just as he was entering the cockpit.
Shortly after takeoff, at an altitude of approximately 40 feet, the aircraft began to roll to the left. The pilot attempted to correct this by applying aileron input, but instead of correcting the bank, the roll intensified. The aircraft subsequently entered a steep, nose-down descent, striking the ground with significant force. The pilot sustained serious injuries and was trapped in the wreckage.
The investigation
The AAIB investigation focused on the mechanical state of the flight controls and the rigging process. While the aircraft showed no signs of structural failure prior to impact, engineers discovered that the aileron control cables had been rigged in the reverse direction. Specifically, the cables were connected to the aileron yoke in a manner that caused the ailerons to move in the opposite direction of the pilot's control stick inputs.
Investigators found that the cable connectors were physically identical, with no unique markings or color coding to distinguish them. Although a warning placard was present in the cockpit, the pilot's interrupted rigging process and a failure to verify the direction of aileron movement during the pre-takeoff vital actions meant the error went undetected. The investigation also noted that the pilot had checked that the controls moved, but had not confirmed they moved in the correct sense.
Findings
- The aileron control cables were incorrectly connected to the aileron yoke in reverse.
- The pilot was distracted by interruptions during the aircraft rigging process.
- The pre-takeoff control check failed to verify that the ailerons moved in the correct direction.
- The control cable connectors were identical and lacked distinctive markings to prevent accidental cross-connection.
Safety action
Following the accident, the UK agent for the Skyranger developed a modification for the aileron control cable end fittings. This new design mechanically prevents the cables from being inadvertently cross-connected to the yoke.