Airway Transportation Systems Specialist The Airway Transportation Systems Specialists (ATSS) at this level is recognized as the subject matter expert in their field. All duties of an ATSS are tied to maintaining safe and efficient operating capacity of the vast and complex network of electronics systems required for the world's largest air traffic control and navigation system. ATSS personnel install, evaluate, maintain, modify and certify facilities, services and equipment that support the National Airspace System (NAS).