An up or down arrow on the TCAS page appears when a target aircraft is climbing or descending at what rate?

The correct answer indicates that the up or down arrow displayed on the TCAS (Traffic Advisory System) page highlights a target aircraft that is climbing or descending specifically at a rate of 500 feet per minute. This information is crucial for pilots as it provides real-time data about the vertical movement of nearby aircraft, which helps in maintaining safe separation.

Understanding the significance of this 500 ft/min threshold helps pilots assess the potential risk of collision or the need for evasive action. When an aircraft is changing altitude at this rate, it becomes essential for the pilot to be aware, as this could influence their tactical decisions in navigating traffic. The TCAS system is designed to enhance awareness during flight, and this rate of altitude change alerts pilots to increased potential interactions with other aircraft, thereby enhancing safety in the airspace.