Page 15 - TNTMay18

Visual or IFR?
The TEB tower controllers mentioned that previous aircraft started the circle at 3.8 miles. This is outside the obstacle-protected area for any category aircraft. This fact raises the question: is it now a visual approach? Are all circling maneuvers visual?
Assuming the Lear 35 approaches at CAT C (121-140 knots ground speed) or even CAT D (141-165 knots ground speed), then beginning the circling portion of the maneu- ver about 3.8 nm from the runway would not be autho- rized. It would be if the Lear was ying at 166 knots ground speed or greater, but I don’t think even a Lear 35 is routinely that fast in a circle-to-land maneuver.
Conditions at the time of the accident were 5,500 scattered, visibility 10 miles; in other words, good VMC. Therefore:
• If ATC cleared the ight for a visual approach, the pilot could (and probably should) have maneuvered to align with Runway 1 farther from the airport than he did.
• If ATC cleared the pilot for the circling approach, even though that portion of the ight was in VMC, the pilot is obligated to adhere to the circling altitudes and radii to comply with that clearance. That said, the pilot is also required to miss the ap- proach if he/she cannot descend below Minimum Descent Altitude (MDA) using “normal maneuvers,” which is not strictly de ned but using a “reasonability test” does not include low-altitude near-knife edge maneuvering like the accident airplane was observed to do.
• The circle-to-land portion of a circling approach must be done with visual contact with the airport, but conditions do not have to be VMC, only the minimum visibility published for that approach and clear of clouds. It is an Instrument Flight Rules procedure that requires outside visual contact to perform. So, the circle-to-land maneuver is a visual procedure, but not a VFR procedure.
Circling Radii: Not What You Might Think
The rules about protected airspace in a circle-to-land maneuver are probably different than you learned when you earned your instrument rating or ATP. Since 2012, the radius of the protected area centered on the ends of the runways changes with changes in altitude above Mean Sea Level.
Although the circling radius is based on the aircraft’s ground speed, this takes into the account the higher True Airspeed for a given indicated airspeed at a higher altitude. It may seem academic (after all, even longer radii than you originally learned apply at higher elevation airports), but the “most correct answer” is no longer a single protected airspace radius for each approach category listed on an instrument approach chart.
May 2018 TWIN & TURBINE • 13