We move into the Yellow Zone whenever we must divide our time more equally between flight planning, monitoring, and control. Decisions have the time constraint of tens of seconds up to a minute or so. Attention usually focuses on events within a 1000 foot (300 m) sphere about the aircraft, although this circle may be enlarged depending on the closing speed of other aircraft in high traffic areas. In the ‘Yellow’ pilots can expect to spend almost equal amounts of time planning, monitoring, and controlling. Such situations as entering the circuit, or thermalling for gliders are representative of being in the ‘Yellow’.