What TCAS warning indicates that the intruder encounter has ended and the aircraft should return to the previous flight level?

The "CLEAR OF CONFLICT" warning is an important announcement from the Traffic Collision Avoidance System (TCAS), indicating that an aircraft has successfully resolved an intruder encounter. When this warning is issued, it signifies that the potential collision risk has been eliminated, and the aircraft can safely return to its previous flight level and normal operations. This reduction in threat allows pilots to cease any evasive maneuvers they may have been executing in response to the intruder's presence.

In this context, other options are not relevant to indicating the resolution of a conflict. For example, requests to "STAY ON CURRENT COURSE" do not suggest that the conflict is resolved, while “PREPARE FOR LANDING” pertains to landing procedures rather than conflict resolution. Similarly, "CROSS CHECK AIRCRAFT POSITION" pertains to verifying the location of the aircraft rather than denoting the end of a traffic conflict. Thus, "CLEAR OF CONFLICT" accurately conveys the conclusion of an intruder encounter, allowing pilots to resume their previous flight path.