Collision Avoidance: ADS-B or TCAS March 7, 2000 INTRODUCTION Background Collision avoidance is something that has been a problem in aviation for a long time. Most of the flights conducted today rely on the see and avoid concept and ground radar. Both of which have their flaws. The FAA predicts that mid-air collisions will increase by 300% over the next 20 years due to the increase in flights being flown by all areas of the aviation community (Kraus xiv). Civil aircraft have had onboard protection from midair collisions only since 1990 and general aviation aircraft are not required to have any collision avoidance technology onboard(www.cassd.org 1). In order to effectively manage the national airspace system in the future we will need to implement Free Flight. Free Flight is a concept designed to enhance safety and efficiency of the airspace by allowing aircraft to choose their own route instead of using victor airways (www.ads-b.com 1). Along with this freedom there is still the problem of aircraft separation which when on an instrument flight plan is air traffic control's (ATC) responsibility. In free flight there may be areas where ATC cannot give the required collision avoidance necessary. In order to safely manage the safety zone around an aircraft, pilots will need to rely on systems installed in the aircraft for better separation. Purpose The purpose of this report is to identify whether Automatic Dependence Surveillance Broadcast (ADS-B) or Traffic Alert and Collision Avoidance System (TCAS II) should be placed in all aircraft if the FAA decides that there is a need for some collision avoidance technology to be required for all aircraft. TCAS is currently required on all commercial passenger aircraft over 30 seats and ADS-B is currently being tested.