Which of the following is a requirement when responding to a TCAS alert?

Compliance with the Resolution Advisory (RA) instructions is crucial when responding to a TCAS (Traffic Alert and Collision Avoidance System) alert. The primary purpose of TCAS is to enhance overall flight safety by providing pilots with automated alerts about potential mid-air collisions. When a TCAS alert occurs, the system generates RA instructions designed to prevent an impending conflict based on the positions and trajectories of nearby aircraft.

Following these RA instructions is essential because they provide specific guidance on how to adjust the aircraft's altitude or course to ensure safe separation from intruding traffic. The emphasis is on following these instructions unless doing so would compromise the safety of the aircraft in a different way. This means that while pilot discretion is important, maintaining safety remains the top priority.

In this context, the requirement to follow RA instructions underscores TCAS's role as a critical safety system, aiming to allow pilots to manage an impending conflict efficiently and effectively.