What is the key difference between a TCAS Traffic Advisory (TA) and a Resolution Advisory (RA)?

The key distinction between a Traffic Advisory (TA) and a Resolution Advisory (RA) in the context of TCAS (Traffic Collision Avoidance System) is that a TA serves as a warning or alert to pilots about nearby traffic that may pose a collision risk, while an RA not only alerts the pilots but also prescribes necessary actions to avoid a potential conflict.

A Traffic Advisory is meant to inform the pilots of the presence of nearby aircraft that could become a threat based on their trajectory. It enhances situational awareness, enabling pilots to visually assess the situation. However, it does not dictate any specific maneuvers or actions that the crew must take.

In contrast, a Resolution Advisory is a more critical alert that indicates the need for immediate action. It provides specific guidance on how to respond to avoid a collision, such as climbing or descending to a certain altitude. This dual nature of an RA, which both alerts and instructs regarding essential maneuvers, is what clearly differentiates it from a TA.

This understanding is crucial for pilots, as it shapes how they prioritize their responses to potential collision risks in real-time flying situations.