Cirlce to land

2 Answers

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   John D Collins on Jul 13, 2017

   What you need to keep in sight is covered in 91.175 (e) (2). I will leave it to you to quote 91.175 (e) (2) if reading it does not answer your question.

   Since obstacle clearance is only evaluated within the circling radius appropriate for your category of aircraft or speed, it behooves you to remain within the radius and to know where you are. The circling radius is a maximum, and often you will need to be closer to the airport if visibility is at the minimums. Remember the circle is a visual maneuver and you must be in visual conditions to see and avoid any obstacle.

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   R. Anderson on Jul 20, 2017

   Also, to add to John’s answer above, keep in mind that when conducting a “circling approach” you are visually circling at or above the MDA using an identifiable part of the airport, not the runway. Of course, to descend below the circling MDA minimum, you must be in compliance with 91.175 (c), which would apply to the runway you are intending to use.

   Some airports are so large (expansive) enough that you would not necessarily see the actual approach end of the runway you are circling to at the published visibility minimum. To complete the maneuver you would actually start the turn toward the landing runway using the airport environment for visual reference and not see the actual end of the runway you are circling to until a later point in the maneuver.

   Circling approaches during minimum published visibility conditions can be very risky and should only be done in full consideration of the hazards involved. For this reason, many Part 121 air carriers do not permit circling approaches at all. Some restrict circling to weather conditions at or above VFR (1000/3). But, circling using published minimums is necessary for some Part 121 carriers because of the airports they operate to. These crews must be specifically trained on circling approaches if they are authorized to be conducted.

   Next, with respect to part 2 of your question, take a look at AIM para. 5-4-20. You will see what the obstacle-considered circling radius is based on. The pilot is responsible for remaining inside of the appropriate obstacle protected airspace. There is not much (or any at all) clearance from obstacles when you are at the MDA outside of the protected airspace, so be very careful during the day and especially at night.

   Finally, currently published circling approaches designed prior to late 2012 will have a smaller (by radius) protected airspace than those designed after late 2012. The new procedures add a bit of safety because the distance away from the airport you may circle will be (generally) greater. Thus, required bank angle while turning (to stay within protected airspace, for example), will be less. This increases safety and often, because the new protected airspace is larger, the minimums will be higher. Please review the AIM and some approach plates to understand what the protected airspace provides by way of obstacle clearance and the specifics of the older and newer designs.

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