Recent guidance from the U.S. Federal Aviation Administration suggests that self separation needs to be a component of an Unmanned Aircraft System Sense and Avoid solution. The greater time horizon associated with self separation allows for pilot-in-the-loop operation, and, in fact, the nature of self separation demands more pilot involvement. The ability to effectively conduct pilot-in-the-loop self separation will be critically dependent on decision aides and advanced displays that allow pilots to make accurate and timely maneuvering decisions. This paper starts with a presentation of eight criteria that should be considered when defining requirements for a future separation assurance and collision avoidance system. Using these criteria, it is illustrated how the concept of conflict probing and the associated scalability enables a range of possible implementations, specifically matched to the available data, interfaces and displays.