The number of airplanes flying through our airspace is growing every day. The frequency congestion as a result of voice communication as the only tool of transmitting necessary information is cousing great workload for air traffic controllers and making the situation unmanageable. The book refers to CPDLC options of usage as a completion, or replacement of voice communication. It deals with practical simulation of air traffic control situated in terminal maneuvering area. To reach desired results an application software had been designed for Data Link communication simulation, called DLCSim, which allows direct connection between controllers and pilots. DLCSim is based and meet the conditions set by EUROCONTROL organization. The experiment attended overall seven participants, which were separated into the groups of controllers, pseudopilots and into the group of pilots flying on B58 flight simulator. The book is focused on searching appropriate way to place CPDLC system and its usage in dynamic environment of arriving and departing traffic.