Airworthiness Directives; Airbus Model A319, A320, and A321 Series Airplanes
We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as: In 2005 a lateral runway excursion occurred on an A320 aircraft. Such excursions are classified as hazardous, with a large reduction in safety margins. Investigation has shown that the aircraft landed with the nose wheels rotated nearly 20 degrees from center. During subsequent tests on the removed BSCU [Braking and Steering Control Unit], a BSCU hardware failure was found, affecting the monitoring function, including the system reconfiguration management, and leading to a runaway of [the] Nose Wheel Steering [uncommanded steering]. An uncommanded steering condition during takeoff or landing could result in departure of the airplane from the runway. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.