Collision avoidance system

This regulation requires all airplanes operated under Part 121 (scheduled air carrier operations) to be equipped with collision avoidance systems as of January 1, 2005. The specific requirements are detailed in a table that follows this regulation text.

In practice, this means Part 121 operators must install and properly operate Traffic Alert and Collision Avoidance System (TCAS) equipment in their aircraft. The system provides automated warnings when other aircraft come too close, helping pilots avoid mid-air collisions. The equipment must not only be installed but also operated according to the specifications in the accompanying table.

This is a critical safety requirement for airline operations. As a pilot flying for a Part 121 carrier, you must understand how to respond to TCAS alerts (Traffic Advisories and Resolution Advisories) and follow the system's guidance during potential conflict situations. The regulation has been in effect for nearly two decades, making TCAS standard equipment on all airline aircraft.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*