Posted for "Bruce Gray" <Bruce@glasair.org>:

An overhead 360 degree circling approach has a high key, break, and low
key. The high key is the point upwind on the runway heading, normally 1
mile out from the approach end (although it can be over the end) of the
runway where the maneuver is initiated. This is the highest point in the
circle, hence the 'high key' name. From practice or brief, you know the
AGL altitude that has to be hit at the high key. Next is the break, we all know that this is the point where the 360
degree turn starts, with a smart 60 degree bank to the left or right and
a power reduction. G forces will kill your airspeed and the turn
continues around to downwind and the low key.

The low key is that point were the turn to base and final starts and it
also has a predefined minimum altitude for the aircraft.

The overhead approach was developed by the military to give you the best
chance of making a successful dead stick landing with an airplane that
had the gliding characteristics of a brick.

Bruce
www.glasair.org