I'm training to be an ATC on VATSIM, and the term "valid departure gate" is tossed about a lot, but not (to my perception) defined. Googling "departure gate" drowns me in passenger terminal maps and notes about what TSA will make me throw away before being allowed to board my plane.

This question about 'arrival gates' seems to clear that up, but since my first role on VATSIM will be verifying that routes are kosher as Delivery controller I wan to be as clear as possible:

Is a departure gate always the final fix on a SID/Transition? Or should I be double-checking additional fixes along the route (when there's no preferred route to check against) to ensure that they're crossing from our center to another center correctly?


2 Answers 2


Departure gates are defined in the Letter of Agreement (LOA) between the approach control and the enroute facility (ARTCC). The LOA will define which aircraft are required to be routed through the departure gate (not all departure aircraft are necessarily required to be routed through the gate). Departure gates are normally drawn on the LOA annex on the approach control/ARTCC boundary and are typically 10-15 miles in length, although that can vary from LOA to LOA.

Enroute automation (ERAM) will normally be adapted to revise the route of flight for departures that are not filed through a gate, reducing controller workload.

  • $\begingroup$ So that sounds like "They're not strict at all, they have nothing to do with each other except by coincidence," if I read you correctly? $\endgroup$ Commented Mar 22, 2022 at 13:08
  • 1
    $\begingroup$ Whether a SID and a departure gate have anything to do with one another depends on the operation. At medium sized airports with an associated approach control, departure gates may be required and they may coincide with the SIDS. At large airports, gates aren't used much because the LOA says something like, "all aircraft will be established on an RNAV SID or vectored through a departure gate." Since almost all airliners are RNAV equipped, the departure gates get used very infrequently. $\endgroup$
    – RetiredATC
    Commented Mar 22, 2022 at 16:36

The gate is usually the last (departure) or first (arrival) fix that is shared between all the transitions, which is the end of the “basic” SID/STAR. The gate is often itself listed as one of the transitions, and such a procedure is typically named after its gate.

There are also some SIDs/STARs that don’t have a “basic” section; the textual description will say to expect radar vectors to/from the first fix on your transition, which is probably your gate. Such a procedure is typically named after the airport itself, a VOR near the airport, or something else that obviously isn’t a gate.

Either way, gates are usually on the border between facilities, which can help identify where those boundaries are if you don’t already know.

But there are always exceptions, so if you have specific examples in mind, please add that to your question.


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