Originally Posted by
KC10 FATboy
Why does the FAA make things so complicated? PANS-OPS has the better way of designing these procedures. FAA procedures don't do, or don't do a very good job of dealing with the effects of altitude on turn radius and the effects of wind. PANS-OPS gives you a buffer, so if you find yourself 0.1NM outside the radii, you don't hit anything. With TERPs, all bets are off.
Did you read the article?
Those are some of the issues that the new criteria takes into account which were not included in the old criteria. The article stills says that the radii are smaller than PAN-OPS though.
As result, FAA conducted an extensive review that resulted in new TERPS criteria that increases the radii dimensions defining the circling protected airspace. In addition, the radii dimensions increase in size as circling MDA increases (Fig 3). This increase in radii size with higher MDAs accounts for greater true airspeeds and adverse wind gradients encountered at higher mean sea level (MSL) altitudes. While these radii are smaller than those used in ICAOs PANS-OPS, they represent a significant improvement over the previous TERPS criteria.