1)
A pilot who declares an emergency
2)
An aircraft that appears to be in a state of emergency, but is apparently not able to inform you
3)
A pilot who reports that the A/C may be compelled to land because of factors affecting the safe operation of the A/C, other than minimum fuel or a fuel emergency
4)
Medical evacuation flights or an A/C that declares a medical emergency
5)
Military or civilian A/C identified as Rescue and the designator RSCU followed by an appropriate flight #
6)
Military A/C departing on active scrambles or operational air defense flights
7)
Open skies treaty flights with designators F and D
8)
Military A/C departing on planned and coordinated Air defense exercises