Have you flown a circle-to-land approach recently, for real? By any chance did you notice that down in the profile view at the bottom, where the circling minimums are shown, the letter “C” is now in bold and it is just slightly larger? You might have missed it. I have pointed this out to some gray beard, veteran pilots who were surprised to see this.
Guess what? You won’t find these everywhere. Only some airports have the newer circling minimums published, right now. But in the next few years, more will have them. So let’s see what’s changed.
It seems that about three years ago, in late 2012, the folks in the FAA who created the TERPS (Terminal Instrument Procedures), which IAPs (instrument approach procedures) are based on, changed it to correct some long standing charting issues that were not properly addressed the first time. Finally.
The FAA is finally getting in sync with other (ICAO) countries around the world regarding circling approaches and obstacle clearance requirements. Do you know how little obstacle clearance there really is? Not a lot. More on that, later. This is important stuff on some dark and stormy night, close to high terrain, when you are considering circling. There are three problems that have long needed to be addressed, and now they have been.
First, the “circling approach protected area” within the radius of the runway end (AIM 5-4-20, b. 1. circling approach protected areas), has changed and AIM Figure 5-4-27 illustrates this. A circling approach might require an excessive bank angle for maneuvering to line up with the runway for landing, and also, because the protected area does not account for wind.
Second: Now it’s all about flying a stabilized final approach, especially if you are in the big iron. Big airplanes (read “jets”) are not designed to be maneuvered close to the ground that way. The really important point is that it does not allow for a stabilized final approach from a point at least 500’ above the runway to landing, which Transport Category (FAR 25) aircraft require for a “stabilized approach.”
Third: The same protected area criterion for circling approaches was used for all airports regardless of field elevation (MSL). So, regardless of whether you were circling in the flat lands of the Midwest or the Colorado Rockies (Aspen or Telluride, Colorado), the circling approaches were designed similarly. Thus, chart designers did not account for the higher true airspeeds in the traffic pattern found at higher elevation airports.
What changes will you see? Expect higher MDAs as the circling radii has been enlarged, so now more, taller structures (read: “obstacles”) are included. Did you know, and are you aware, that up until now, there has been no buffer zone outside of this protected area? Whoa. So, for example, if the radius for Category C is 1.7nm, there could be a 1000’ obstacle at 1.71nm, that is, one-tenth of a nautical mile beyond the protected zone! That is not much protection. With the newer guidelines, the new circling criteria provide a 1+ nm buffer outside the protected area. This increases the safety margin considerably when you are circling in marginal conditions. I like this.
This is also why many, if not most, operators of large turbine aircraft (airlines as well as many corporate operators) do not permit circling approaches unless the weather conditions are at least 1000 ft. and 3SM, in daytime VMC conditions. Large transport category jets and turboprops are not designed to be maneuvered down low, close to the terrain, not stabilized, especially at night, in marginal conditions. So they are prohibited from doing this. Passengers appreciate this, as well.
With this change, the FAA has apparently moved closer to ICAO guidelines for determining the circling minimums for an approach. So, be sure to look more closely at the circling minimums portion of the Jepp or NOS approach plate the next time you consider a circling approach.
Have you ever trained in an FAA Level C or D simulator, at a FAR 142 training facility like those at FlightSafety International, CAE Simuflite, or SimCom? If not, then welcome to the world of simulator training, in a full-motion flight-training device (FTD). When flying a circling approach in a Level C or D simulator, it is required to be conducted in a “night-time” environment, when it is dark, which can add to the difficulty and stress level, until you become familiar with these conditions.
If you have, then you are familiar with the circling approaches that are typically flown there. The circling approaches are usually at either JFK International Airport (KJFK) or Memphis, Tennessee (KMEM). Why these two, you ask? The runway layout at both KJFK and KMEM meet the FAA’s criteria for circling approaches in a simulator, where the requirements include circling to a runway that is at least 90 degrees offset from the approach in use.
So for example, at KMEM, you fly either the ILS/Localizer or RNAV 27 approach and then circle or maneuver (offset) north to land on runway 18 Right. Typically you fly this approach using all available automation (coupled to the autopilot/flight director/flight guidance), until it is necessary to circle or make the descending left turn to the landing runway (18R), and you hand-fly that portion of the approach to a landing. This takes some getting used to. The descent from the circling MDA to the runway needs to be a stabilized descent, not exceeding 1,000’ feet per minute on final, touching down in the touch down zone (TDZ).
If the descent to the runway does momentarily exceed 1000’ FPM, this might trigger a loud ground proximity warning system (GPWS) alert (“Sink Rate, Sink Rate”) which is designed to get your attention. You would respond to this with prompt, corrective action, briefly leveling off and adding some power as required, momentarily slowing the decent, then resuming a stabilized final approach to the runway.
So, if possible, don’t fly a circling approach to an unfamiliar airport, at night, for the first time. This is not a good idea. It is best to fly a circling approach in day VMC conditions if at all possible, so you can see the terrain and the surrounding area, before attempting this at night. This is especially true if there is any hilly or mountainous terrain in the vicinity. Then you will probably want to avoid circling there after dark.
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Good info. Thanks.
Just a few years late. These changes, while continually working their way into the system, took place in 2012.
I know, I know… just ’cause it’s been around for a while doesn’t mean folks know about it.
For your next article, perhaps you can discuss cold temperature adjustments to approach minimums… That has it’s own iconography in the plates, too, and has been around even longer than the new circling radii, but I’ll betcha lots o’ folks have never heard of it.
Yes, as you correctly point out, these changes have been in affect since 2012. But, how many pilots are aware of this change? I recently had a client, who is a retired airline pilot now flying corporate, who was not aware of this, when I pointed it out. So it would seem that there are at least a few that still not aware. Hopefully this brings it to their attention.
Thank you for your suggestion for an article. I will dig into this and see what I can come up with.
The fussbudget patrol notes that the difference between 1.71 NM and 1.7 NM is one one-hundredth, not one-tenth. Nevertheless, thanks for the informative article. Personally, I avoid circling approaches if I possibly can.
Oops, sorry. Thanks for pointing that out. I obviously did not catch that. Appreciate your feedback. Agreed, caution advised, especially when circling. Fly safely!
Allow me to present another view.
Back when we were flying DC-3s, the basic three hundred and one circing approach was developed. With suitable training it worked great. Most of our smaller GA airplanes fit the same airspace as did the DC-3.
Unfortunately, the techniques are no longer being taught properly. Consequently we have lost the use of some excellent approach possibilities.
For several years I taught a seminar on low visibilty and circling approaches. It was just the same stuff I was taught in 1951. Worked very well back then and can be used roday, IF we teach it properly.
There is nothing magic about the three degree glide path. Six degrees works great for a DC-3 or a Bonanza.
A circling approach which has a turning base and final keeps the runway in sight and can be just as stabilized as any straight in approach.
Worked for years with the DC-3.
I rember once reading something from Jimmyl Doolittle where he said there has never been an airplane built that had a better safety record than the DC-3 per takeoff and landing
However, good technique needs to be taught and who is available today to provide that training?
ATP Typed in many machines from the DC-3 through the 747
Circle the way that passes the common sense test, not the way the Tower tells you. You have three options: early break-off from final app crs, overfly the field and set up for the desired rw or go missed. Don’t get pushed into a circle you don’t like for the sake of expediting traffic, e.g. Learjet accident at KTEB of 15 May 17.