enter image description here
(skyvector.com, modified)

The Springfield, OH airport, KSGH, is a non-towered airport with both precision and non-precision instrument approach procedures. To support these approaches, there are a couple of "keyhole" Class E transition areas; however, these particular Class E transition areas start from the surface (magenta dashed lines) depicted on VFR Sectional Charts.

I'm really confused how the Class E areas extend from the surface when the airspace directly over the non-towered airport is Class G. Is it possible that the VFR Charts are in error and the magenta dashed line should be removed or converted to a magenta vignette indicating that the Class E starts at 700' AGL?

There are several indications in my mind that this is simply depicted as an error on the VFR Sectionals:

  1. The VFR Sectional says, "See NOTAMs/Supplement for Class E (sf) eff hrs"; however, when consulting the Central Eastern Supplement for KSGH, there is no "Airspace" item listed under the airport. Which substantiates the VFR Sectional chart designation that the airspace directly above the airport is Class G.

  2. Since there is no "Airspace" in the Supplement (nor NOTAMs), there is no "effective hours" as the VFR Chart suggests that there should be for the two depicted Class E (sfc) areas.

  3. As depicted, it appears as if the a pilot could enter Class E controlled airspace and then quickly transition out of it and into Class G uncontrolled airspace as they continue on the approach. This doesn't make sense when you consider the intent of the Class E transition areas are to help IFR traffic be provided separation from Class G traffic.

  4. The Airman's Information Manual (para 3-2-6.e.2) describes "Class E airspace may be designated as extensions to Class B, Class C, Class D, and Class E surface areas." It does not include Class G airspace in that list of airspaces that Class E may be designated as an extension.

  5. The AIM (para 3-2-6.e.2) goes on to say, "Surface area arrival extensions become part of the surface area and are in effect during the same times as the surface area." Since there is no surface area in effect, it seems to be another indicator that the Class E (sfc) is also not in effect.

Can anyone explain how it's possible for these two Class E (sfc) areas to be legitimately marked, or are they simply errors?

  • $\begingroup$ Airspace directly above KSGH is Class E at 700' AGL. There is the magenta vignette surrounding a big area on the sectional chart. $\endgroup$
    – wbeard52
    Commented Feb 14, 2017 at 18:03
  • $\begingroup$ My guess is that there was Class E or D to the surface surrounding the airport in the past, which was subsequently eliminated, but the extensions were not changed. $\endgroup$
    – J W
    Commented Feb 14, 2017 at 18:19

2 Answers 2


There was a control tower at SGH which closed. The FAA issued a rule which removed the Class D airspace as of December 10, 2015.

This leaves the class E airspace chunks. As you noted, the Chart Supplement for SGH has no information about the airspace, and FAA Order 7400.11A (the current version of airspace definitions) states only that, after an initial NOTAM announcing the effective dates and times, (p. E-183)

The effective dates and times will thereafter be continuously published in the Airport/Facility Directory.

So, is the airspace between the surface and 700AGL in these two areas class E or G? I'm not a lawyer, but I think you could make a strong argument for the airspace being class G, unless the chart supplement gets an update or a NOTAM is issued.

Finally, to the question: why are these two areas there? Two thoughts come to mind.

  • The class E extensions existed alongside the class D airspace, and nobody thought to remove them. (This is the most likely, to me.)
  • There is some other operational reason for the class E airspace. There are instrument approaches to the field, though they terminate well inside the radius of the two airspace segments, so that's not very likely. Also, the class D airspace could be reactivated by NOTAM if a high-traffic event at SGH were to occur; the class E extensions could be part of that. However, both of these options are really stretches - my guess is that we've found airspace that someone just forgot.

2019 update: those extensions are no longer visible on the sectionals:

enter image description here

  • 1
    $\begingroup$ Yup, this is what I thought too. Thanks for confirming what I was seeing. Why is it important? I am also a Remote Pilot (Part 107) and if this airspace is Class E to the surface, we are restricted from flying within the lateral boundaries without an FAA waiver, even if though we are restricted to flying below 400'. And the FAA is very slow at approving these waivers. However, filing a waiver request might give them a little more reason to fix their oversight. The other funny thing about this is that KSGH is in the process of getting special permission to fly UAVs at the airport! $\endgroup$
    – scottfred
    Commented Feb 14, 2017 at 23:28
  • $\begingroup$ Here's are links to information about civilian and military organizations attempting to get approval to operate UAVs out of this airport. $\endgroup$
    – scottfred
    Commented Feb 14, 2017 at 23:29
  • $\begingroup$ BTW -- aircraft on the IAPs are well above the 700' AGL floor of the surrounding E airspace when in those "keyhole" areas, so that's not why they were left behind. $\endgroup$ Commented Feb 15, 2017 at 4:41
  • $\begingroup$ Everything in the above answer is true; the last guess at the end is the correct one. I found an authoritative link that enables a shorter answer. Re the Remote Pilot's comment --see the January 10 2018 Memorandum re SUA flight in class-E-to-surface extensions-- goldsealgroundschool.com/uav-library/… as discussed here aviation.stackexchange.com/questions/35297/… . You should be fine to fly in those keyholes. A bit late to tell you now-- $\endgroup$ Commented Oct 7, 2018 at 21:55
  • $\begingroup$ The above comment should have read, "the first guess at the end is the correct one." $\endgroup$ Commented May 4, 2019 at 21:53

Class-E-to-surface "extensions" are supposed to abut Class D or higher airspace, not stand alone like this. Or they can abut a Class-E-to-surface circle or other shape surrounding the airport in question-- most frequently this involves the particular case where Class D or higher airspace surrounding the airport has temporarily reverted to Class-E-to-surface due to the tower being closed for the night. There are however a few exceptions where no tower is involved, and full-time Class-E-to-surface "extensions" abut a full-time Class-E-to-surface circle around the airport-- some examples are given in the related ASE question What is the primary reason that the non-towered airports KACV and KTVL have E4 extensions to E2 airspace? . So the literal answer to the actual title of your question is "yes". However, Class-E-to-surface "extensions" are never supposed to stand alone as illustrated here.

The FAA simply forgot to remove the Class-E-to-surface "extensions" after they closed the tower and removed the Class D airspace. They are fixing it now-- the "extensions" will go away in November 2018. See-- https://www.federalregister.gov/documents/2018/09/10/2018-19475/revocation-of-class-e-airspace-springfield-oh

  • $\begingroup$ Kind of late to run across this question now but better late than never? $\endgroup$ Commented Oct 7, 2018 at 22:09
  • $\begingroup$ Have since learned that it's possible for an E4 extension to adjoin an E2 circle even if no tower is involved-- see for example aviation.stackexchange.com/questions/63970/… . This is extremely rare though, and could not account for E4 extensions simply standing alone not connected to anything $\endgroup$ Commented May 12, 2019 at 19:09
  • 1
    $\begingroup$ (ran across this old answer again recently and edited to include info in last comment) $\endgroup$ Commented Jan 31, 2021 at 21:40

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