The Traffic Alert and Collision Avoidance System (TCAS)

On June 23, 1981, Federal Aviation Administration (FAA) Administrator J. Lynn Helms announced the FAA’s decision to adopt the threat alert and collision avoidance system, soon renamed the traffic alert and collision avoidance system (TCAS).

If there is a potential collision developing, the TCAS alerts the pilots and provides climb/descend instructions to them. In 1981, Piedmont Airlines flew the first operational TCAS on a regularly scheduled flight. Two Piedmont Boeing 727s flew with specially trained observers to validate the system, which worked.

In 1993, the FAA required all airliners with more than 30 seats to have TCAS, and since it became a standard equipment in airliners, the risk of mid-air collision dropped dramatically.