In a procedure similar to the IP concept, the military uses key positions. "You have a high key position, right over the approach end of the runway, where you're going to be making a constant 360-degree turn," Gibson says. "The 180-degree position is called low key, and that is probably going to be 1,200 to 1,500 feet. You need to know what your high key altitude is and what your low key altitude is for your particular airplane because, if you're headed to a runway and you get yourself down to an altitude that is below high key, you know you can't make a whole 360-degree turn. In that case you have to drive to your low key position."