In the US, there are some airports with a part-time tower. When the tower is in operation, the airspace around the airport is class D and requires communication with the tower. When the tower is closed, the airspace would be either class E or G (depending on height AGL) and pilots would land at the airport like they would an untowered airport. (Right?)

Assuming that is true, what happens to traffic already in the area when airspace becomes class D with communication requirements? Are the pilots supposed to "evacuate" the airspace before when it becomes class D? Or are they "adopted" by the tower when it opens?

If they are "adopted" what is that process and communication like?

If there is already a "busy" class E & G pattern (maybe with 3 airplanes in the pattern and one having just touched down) in process, what would we be likely to hear from the tower as they open? (Are there any separation requirements that class D airspace control would be trying to meet that a "busy" class E/G traffic pattern would not meet?)


1 Answer 1


FAA's Facility Operation and Administration says (emphasis mine):

Part-time facilities must establish procedures for opening and closing their facilities. The procedures must be coordinated with the facility having IFR jurisdiction and must include, as a minimum, the following:

a. Broadcast an announcement upon resuming/terminating service on appropriate frequencies. This broadcast must include, as a minimum, a statement that indicates ATC service and the airspace class of service being resumed or terminated, e.g, "[Time] Waukesha Tower is terminating Class Delta services Class E/G Airspace now in effect."

One of AC 90-66B's references is an AOPA pamphlet that mentions that in a typical arrangement, the CTAF frequency is the same as the tower's, meaning in most cases it will be a seamless transition with the controller already having a picture of what's going on.

So to answer your questions:

  • The tower will make an announcement (example quoted above)
  • Existing traffic will be absorbed (nowhere does it say traffic must evacuate)
  • 6
    $\begingroup$ I've heard anecdotes to the effect of "The time is 0400Z, Podunk Tower is resuming Class Delta services, ATIS Alfa is current. Aircraft on half-mile final runway 18, you are cleared for the option; when able say callsign and intentions." $\endgroup$
    – randomhead
    Nov 4, 2021 at 15:57

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