As noted in this articles main text, the FAA recently revised its criteria describing how much airspace is required to perform the circling maneuver. The new criteria consider the altitude at which the aircraft is circling. The higher the altitude, the greater the true airspeed when circling at the same indicated airspeed, and thus the greater the turn radius, which makes expanding the protected airspace desirable. The downside? Many minimum descent altitudes for circling approaches will be going up. The two tables below compare the previous criteria to the new.
When the new criteria have been applied to the circling minimums, the Aeronav charts will use this symbol:
Absence of the symbol in the circling minimums section of the approach plate means the new criteria have not yet been applied to the procedure. Jeppesens charts use a similar symbol, except in a diamond rather than a square.
