The circling area is calculated using the aircraft category speeds for circling (i.e. B @135kIAS) and assumes (for a 2000 feet elevation aerodrome)
1. A 25 kt wind through the turn
2. 20° angle of bank, or 3° per second, whichever is less.
It's in PANS-OPS. Note - go to some parts of the world and it will be different....
Last edited by compressor stall; 12th June 2012 at 12:52.