Uncommanded rudder inputs on final approach traced to a faulty Airbus A300-600 autopilot have caused the US Federal Aviation Administration to issue an airworthiness directive (AD) requiring autopilot checks on the entire A300B, A310 and A300-600 fleet.

The unidentified incident is still under investigation by the French civil aviation authority (DGAC), but "preliminary results" indicate an installation error in the autopilot actuator control system.

The DGAC says that the incident involved "high rudder forces and uncommanded rudder inputs during final approach". Examination of the autopilot revealed that "the electrical connectors between the yaw actuator's two main valves and the two flight control computers were crossed".

Airbus says that the "erratic rudder movement" was "of small amplitude and easily overcome by pilot input", and that the autopilot problem was an installation or maintenance issue.

Source: Flight International