Airworthiness Directives; Airbus Model A300 B4-600, B4-600R, and F4-600R (Collectively Called A300-600) Series Airplanes; and Model A310 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A300-600 and A310 series airplanes, that requires replacement of certain symbol generator units (SGUs) in the electronic flight instrument system with new, improved SGUs, and modification of associated equipment and wiring. This action is necessary to ensure that the flightcrew has adequate flight information by preventing temporary loss of data from the primary flight and navigation displays. Inadequate flight information could result in reduced situational awareness for the flightcrew, which could contribute to loss of control or impact with obstacles or terrain. This action is intended to address the identified unsafe condition.