Airworthiness Directives; Airbus Airplanes

We propose to adopt a new airworthiness directive (AD) for certain Airbus Model A318, A319, A320, and A321 series airplanes; all Model A330-200 Freighter, -200, and -300 series airplanes; and all Model A340-200, -300, -500, and -600 series airplanes. This proposed AD was prompted by reports of false traffic collision avoidance system (TCAS) resolution advisories. This proposed AD would require modifying the software in the TCAS computer processor or replacing the TCAS computer with a new TCAS computer. We are proposing this AD to address the unsafe condition on these products.