Number: 300 Topic: Air Traffic Control Systems <desc> Description: To be relevant, an item will concern a commercial airline accident anywhere in the world and consider, if not outright attribute, the casualty to a difficulty (either mechanical or human) with an air traffic control system. <narr> Narrative: The U.S. National Air Traffic Controllers Association frequently warns that air traffic control systems around the world are inadequate and that personnel are frequently overworked. Is there evidence in investigation data that the mechanical and human systems worldwide frequently contribute to airliner casualties?