Which advisory is issued by TCAS to alert pilots to other aircraft?

The Traffic Advisory (TA) is the correct choice because it is a specific alert generated by the Traffic Collision Avoidance System (TCAS) to inform pilots of nearby aircraft that may pose a potential threat. When a TA is issued, it prompts pilots to be vigilant and maintain a lookout for other aircraft, but it does not require immediate action. Instead, it serves as a warning to be aware of traffic in the vicinity and is a crucial part of situational awareness during flight.

The significance of the TA lies in its role as an initial alert that prepares pilots to either take precautionary measures or await further instructions. It helps prevent collisions by making pilots conscious of potentially conflicting traffic.

In contrast, the other options refer to different types of advisories or alerts that serve various functions within the cockpit environment. Collision Advisory (CA) is not a standard term used in TCAS operations. Flight Warning (FW) typically pertains to alerts about system malfunctions rather than traffic issues. Resolution Advisory (RA), while relating to TCAS, indicates when a pilot needs to take specific evasive action to avoid a collision, representing a higher level of seriousness than a Traffic Advisory.