Traffic Alert and Collision Avoidance System (TCAS) transition program (TTP): a status update

In response to United States (U.S.) law mandating installation, by December 31, 1993, of TCAS IT on all air carrier aircraft with more than thirty passenger seats operating in U.S. Airspace, the first in-service flight of a certified TCAS II production unit occurred in June 1990. Currently, worldwide installations of TCAS IT in air carrier and business aircraft are estimated at over 7,000 units. Total accumulated flight operations exceed 50 million hours, with over 1.5 million additional hours accumulated each month. This paper provides a status update on the TCAS Transition Program (TTP) which was established to monitor the operational performance and assist with the introduction of TCAS II avionics into the National Airspace System (NAS). The update is provided by means of a qualitative performance comparison between the software logic initially fielded (Version 6.02) and the latest version (Version 6.04A) developed to address various flight performance dynamics and interface issues between TCAS and the air traffic control (ATC) system. This latest software logic has been in operation in all TCAS II-equipped aircraft since January 1, 1995.