Removal of “inverse C” circling icon from approach charts

[MauleSkinner]

Posted over on BeechTalk…

Beginning with the August 7, 2025 publication date, FAA Aeronautical Information Services (AJV-A) will begin removing the Circling Icon from the Minimums section of the Instrument Approach Procedure (IAP) charts and RADAR Instrument Approach Minimums.

Background:
In 2012, there was a change to the TERPS criteria that affected circling area dimension by expanding the areas to provide improved obstacle protection. To indicate that the new criteria had been applied to a given procedure, a was placed on the circling line of minimums.

All circling areas have now been evaluated for the circling MDA protected area radius as shown in the table in the TPP Legend. Users may ignore the presence of the symbol on charts, and they will be removed on a day-forward basis.

The source document…

https://www.faa.gov/air_traffic/flight_info/aeronav/safety_alerts/media/TERM_25-05_Removal_of_Circling_Icon.pdf

 

[RussR]

I'm very glad to see this (finally). I put a lot of work into amending procedures for the new radii.

Fun fact: when the change came out in 2012, AFS (who writes the rules) agreed with the TERPS people (who actually do the design work) that the procedures can just be updated as they came up for amendment for other reasons. (This is standard procedure for most criteria changes). What I don't think AFS counted on was how long this could take. Procedures aren't generally amended unless there's a safety reason, or some ATC or user-requested reason to do so. So it can literally be decades between amendments, especially at smaller airports.

Eventually, in about 2019 AFS basically said to TERPS, "okay guys, that's long enough, you need to just get them done". And my manager volunteered our team to take it on (ugh). By 2022 we were pretty much done with just some stragglers out there.

 

[35 AoA]

I met a gal in the STL airport bar (traveling not for airline work mind you) who i found out does TERPS. She was pretty shocked/confused when i threw out that term in response to her general job description. Anyway, cool that they have adopted the new standards (not that my shop allows us to circle anyway)

 

[midlifeflyer]

Yeah, I got my notice by email the other day. Basically a temporary notation that’s no longer needed.

 

[MauleSkinner]

Yeah, I got my notice by email the other day. Basically a temporary notation that’s no longer needed.

Biggest thing for me is the indication that they finished the project.

Maybe now they can work on making it mandatory for approach fixes with mandatory altitudes to be coded into the approach procedure in my avionics.

 

[midlifeflyer]

Maybe now they can work on making it mandatory for approach fixes with mandatory altitudes to be coded into the approach procedure in my avionics.

It's not already being done? I thought that mandatory altitudes were coded in avionics databases that supported altitude constraints. So I loaded the KORL RNAV 7 into both a GTN and IFD series and the mandatory 1020 at SWLTR was shown in both.

 

[MauleSkinner]

It's not already being done? I thought that mandatory altitudes were coded in avionics databases that supported altitude constraints.
So I loaded the KORL RNAV 7 into both a GTN and IFD series and the mandatory 1020 at SWLTR was shown in both.

Generally speaking, that’s true. But in my 40-year-old system (eh, probably closer to 30), “step down fixes” aren’t coded into the procedure, so SWLTR isn’t going to be there. I forget the guidance, maybe AC 90-100, says I can identify SWLTR by distance to the MAP. Obviously I’m going to have to manually ensure the crossing altitude, and also if I use VNAV it will cross SWLTR at the proper altitude.

Another example is the RNAV X RWY 6 at KTEB…at some point someone somewhere somehow decided to call the fix outside the FAF a “step down fix,” so PESME isn’t coded into the procedure in my box. This is a little more troublesome, because if I let VNAV do the work, I’ll still be at 2000 feet instead of the mandatory 1700 crossing PESME. I was told over 10 years ago that they were going to change that, but apparently it’s low on the priority list.

For the record, I haven’t run across another system that doesn’t include those fixes.

 

[luvflyin]

Generally speaking, that’s true. But in my 40-year-old system, “step down fixes” aren’t coded into the procedure, so SWLTR isn’t going to be there. I forget the guidance, maybe AC 90-100, says I can identify SWLTR by distance to the MAP. Obviously I’m going to have to manually ensure the crossing altitude, and also if I use VNAV it will cross SWLTR at the proper altitude.

Another example is the RNAV X RWY 6 at KTEB…at some point someone somewhere somehow decided to call the fix outside the FAF a “step down fix,” so PESME isn’t coded into the procedure in my box. This is a little more troublesome, because if I let VNAV do the work, I’ll still be at 2000 feet instead of the mandatory 1700 crossing PESME. I was told over 10 years ago that they were going to change that, but apparently it’s low on the priority list.

For the record, I haven’t run across another system that doesn’t include those fixes.

If I remember right, a number of years ago Jepp quit putting waypoints inside the FAF in their database. It was done to save room. There were so many waypoints they were running out of room to put everything in there. Or something like that.

 

[MauleSkinner]

If I remember right, a number of years ago Jepp quit putting waypoints inside the FAF in their database. It was done to save room. There were so many waypoints they were running out of room to put everything in there. Or something like that.

The AMS 5000 has never had fixes inside the FAF, probably for that reason. Calling fixes outside the FAF “step down fixes” is a more recent change, and I was told that “step down fix” label is how the fixes are omitted from the procedure.

 

[RussR]

The AMS 5000 has never had fixes inside the FAF, probably for that reason. Calling fixes outside the FAF “step down fixes” is a more recent change, and I was told that “step down fix” label is how the fixes are omitted from the procedure.

In the ARINC coding world (the specification on how the procedures are encoded into the FMS/GPS), the IF is given a "sequence number" of 010. The FAF is 020 and the MAP is 030. Any fixes between these are incremented by "1". So a fix between the IF and the FAF is 011. A final stepdown fix is 021 (and 022 if there are more, etc.).

So in your example, PESME isn't really "called" a stepdown fix per se, it's just assigned sequence number 011 since it's between the IF and the FAF.

If Collins (right?) is choosing to not display anything that isn't 010, 020 or 030, that's definitely an FMS limitation.

 

[MauleSkinner]

In the ARINC coding world (the specification on how the procedures are encoded into the FMS/GPS), the IF is given a "sequence number" of 010. The FAF is 020 and the MAP is 030. Any fixes between these are incremented by "1". So a fix between the IF and the FAF is 011. A final stepdown fix is 021 (and 022 if there are more, etc.).

So in your example, PESME isn't really "called" a stepdown fix per se, it's just assigned sequence number 011 since it's between the IF and the FAF.

If Collins (right?) is choosing to not display anything that isn't 010, 020 or 030, that's definitely an FMS limitation.

ok, that makes sense.

Something changed about 12 years ago…I know for sure BGTEN on the RNAV Y 5R at KIND and MACEE on the RNAV 36L at KMEM used to be coded in the procedures but aren’t anymore. They do exist in the localizer-based procedures for the same runways, though, for what that’s worth.

 

[midlifeflyer]

If I remember right, a number of years ago Jepp quit putting waypoints inside the FAF in their database. It was done to save room. There were so many waypoints they were running out of room to put everything in there. Or something like that.

If we are talking about the same thing, I came across this some years ago when a DPE asked me. He was doing an instrument checkride and was going to do a local LOC from an ILS OR LOC and found the stepdown wasn't there. I asked Jepp and Garmin (it was a Garmin box) about it and the "best" answer I got was to keep the database smaller. The waypoints were there but not included in the procedure, so you only got the ILS. At the same time, if you used the Garmin database, you got two entries, one for the ILS and one for the LOC. It was one of the only differences I ever saw between the two databases.

I'm not sure when it changed, but within the past year or so I saw that Jepp picked up the Garmin ides - the ILS and the LOC as two different approaches in the database. ILS with no stepdown; LOC with it.

Edit - We can sort of find the change time frame. Avidyne uses the Jepp database. The PC-based IFD trainer, which they stopped supporting about 2018 does not have a LOC; the newer iOS-based one does.

 

[John Collins]

If I recall, all the approaches that used the expanded circling areas were finished a few years ago and any circling minimums that were affected were updated. However they were not all flight tested. As the procedures were flight tested, the circle C got added to the charts. Eventually, it was decided not to continue adding them to the charts because they were subsequently going to be removed once all the procedures were flight tested. My understanding is now that all the procedures have been flight tested, the guidance in the AIM, AIP, Instrument Procedures Handbook, Instrument Flying Handbook, and TPPP guidance need to get updated to explain the change. The next update for these is in August.