New Pilot here, just planning a VFR trip to KGMU but not sure of the transition rules here. I know flight following will take care of the Class C but who do I need to talk to about the other Class D? Who all do I need to talk too and in what order? Maybe I’m overthinking this one but any help would be great.

Screenshot of ForeFlight showing the VFR sectional in the vicinity of Greenville, SC, in particular the interplay between the GSP Class C airspace, GMU Class D airspace, and GYH Class D airspace. There is a magenta line extending from the south of the image through the GYH surface area and terminating at GMU.

  • 1
    $\begingroup$ Question could use a little clarification. You are planning to depart from KGMU (Class D airspace), and plan to fly through KGYH Class D airspace, and want to know who you need to talk to? Also you mention Class C (KGSP) -- do you actually plan to climb into the Class C airspace, and if so, do you plan to that before or after entering the KGYH Class D airspace? It seems unnecessarily complicated to plan to enter both the KGYH Class D airspace and the KGSP Class C airspace, but your question as written seems to hint that that is your plan. Can you clarify? $\endgroup$ Commented Nov 16, 2022 at 16:16
  • 1
    $\begingroup$ (Also, your contention that "flight following will take care of the Class C" may not be correct.) $\endgroup$ Commented Nov 16, 2022 at 16:18
  • $\begingroup$ Sorry flying from KDNL to KGMU. KGSP outer shelf is only 2200 ft on the southwest corner. $\endgroup$
    – Turner
    Commented Nov 16, 2022 at 16:25
  • 1
    $\begingroup$ Are you planning on flying under the 2200 ft. Class C shelf? $\endgroup$
    – user22445
    Commented Nov 16, 2022 at 16:52
  • 1
    $\begingroup$ @quietflyer Why do you say that flight following wouldn't take care of the Class C? If he's talking to ATC, they'll take care of whatever coordination is required, or else advise him what he needs to do or whom to call. What scenario do you foresee where a pilot would need to take actions beyond what the controller who's doing flight following would do? $\endgroup$
    – Ralph J
    Commented Nov 16, 2022 at 17:33

1 Answer 1


On the pilot side the rules are unambiguous. 14 CFR 91.129 (c)(1) requires that you establish two-way communication with "the ATC facility providing air traffic services" before you enter the Class D airspace, unless otherwise authorized in accordance with 91.129 (a). 14 CFR 91.130 (c)(1) requires the same two-way communications prior to entering Class C airspace.

So if you are not on flight following with Greer Approach, you would remain below the Class C shelf (2200' MSL to the south of GSP) and establish contact with Donaldson Tower:

Donaldson Tower, Skyhawk 12345 is ten miles south-southeast at two thousand, transitioning to land Greenville Downtown.

Donaldson Tower will respond with your callsign—which permits you to enter their airspace—and any instructions they might need to issue you. When appropriate, they will either tell you to "Contact Greenville Tower 119.9" or "Frequency change approved." At that point you contact Greenville Tower.

However, as the comments have mentioned, flight following (i.e. radar services from the Greer Approach controller) will be beneficial to you, for three reasons.

First, 91.129 and 91.130 require that you establish communications with "the ATC facility providing air traffic services." This is not always the tower! For example, the hosts of the Opposing Bases podcast work at a Class C approach control that has a satellite Class D tower. They have mentioned that they, the approach controllers, actually own a significant portion of the Class D on the arrival side of the satellite airport—the tower is not the facility providing air traffic services in that part of the airspace, so you would not be fulfilling your 91.129 requirement by contacting them! Another example is the satellite airports in the Boston region; the chart there has a note which says "Aircraft requesting to transit the Class D airspace at or above 2500 MSL contact Boston Approach" even though the surface area goes up to 2600.

Second, if you are talking to a radar controller, the rules they follow tell them to coordinate your surface area transit—or terminate your services—prior to you entering the surface area. There is a Note which says "The pilot is not expected to obtain his/her own authorization through each area when in contact with a radar facility"—but this Note is not, of course, contained in 14 CFR 91.129, so it would still behoove you to confirm that they have coordinated:

Approach, verify Skyhawk 345 may transit the Donaldson Class Delta?

If they say yes, then you may assume that Donaldson Tower—which is "the ATC facility having jurisdiction over the Class D airspace area"—has authorized your being in the airspace despite not establishing communications with them. The authorization is relayed to you by the Approach controller.

Being on flight following also allows you to stay higher for longer because you do not have to avoid the Charlie. This is good because there are some relatively high obstructions in that area, like the 1988' and 1849' towers.

  • $\begingroup$ Thank you so much this answer all of my questions !, $\endgroup$
    – Turner
    Commented Nov 16, 2022 at 22:49
  • 1
    $\begingroup$ Good answer and +1 for opposingbases.com - they discuss this kind of topic in the weekly podcast. I listened to episodes while driving to the airport during my Instrument training and found all their content very useful and often instantly applicable. $\endgroup$ Commented Nov 17, 2022 at 1:06
  • 1
    $\begingroup$ @user2070305 just mind those penguins. $\endgroup$ Commented Nov 17, 2022 at 4:24
  • $\begingroup$ Arguably, if Approach is “the facility providing air traffic services” (in the form of VFRFF), then it doesn’t matter who “owns” that airspace. $\endgroup$
    – StephenS
    Commented Nov 19, 2022 at 19:46

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .