A Systems Engineering Approach to the Redesign of the Traffic Alert and Collision Avoidance System II

The Traffic Alert and Collision Avoidance System II (TCAS II) is an airborne system designed to prevent mid-air collisions by alerting pilots to nearby aircraft and issuing resolution advisories such as climb or descend commands. Following high-profile mid-air collisions, including the 1986 Cerritos crash, TCAS II was mandated by the Federal Aviation Administration for U.S. commercial aircraft. However, its early development and deployment during the 1980s and 1990s encountered significant challenges. Initial versions suffered from unreliable alerts, poor integration with air traffic control, and pilot confusion, which delayed full adoption until system improvements were implemented in the late 1990s.