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Pilots are demanding conventional SID rather than RNAV SID planned on flight plan due gps problem. In that case is it enough for a tower controller to coordinate the conventional SID with the approach unit or should pilots contact with their company to refill the flight plan?

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2 Answers 2

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The SID is normally assigned by the approach controller, not the scheduler, as SIDs are runway dependent and may change at a moment's notice with changing runways and because of noise abatement requirements.

A "default" SID is probably suggested by the airline's planning department based on historical patterns but there's no guarantee you'll actually get it.

If the SID you're actually getting doesn't match the rest of your flightplan, ATC will vector you. Just as ATC will give you instructions at any time they want you to do something that's not filed with them as your flightplan.

The airline has nothing to do with that, though they may want to know afterwards for their statistics and to explain possible extra fuel burn.

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  • $\begingroup$ Just to add, for several departures in Europe there is a note on the chart to inform ATC (or specifically clearance delivery) that one is unable RNAV1 or RNAV (in general). $\endgroup$
    – Timbo
    May 20, 2023 at 14:44
  • $\begingroup$ Is there an area-wide GPS problem or a problem with the equipment on a particular aircraft? $\endgroup$
    – RetiredATC
    May 20, 2023 at 14:47
  • $\begingroup$ Perhaps there is a U.S. SID that is runway dependent. Most are not, and they normally serve various runways at an airport. $\endgroup$
    – user22445
    May 20, 2023 at 17:42
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    $\begingroup$ We had that problem with several aircrafts at Istanbul airport it was not area-wide and yes SID is runway dependent for example for runway 36 SID ivgus4e and for runway 35L it is ivgus4d. $\endgroup$
    – ilayda
    May 20, 2023 at 17:58
  • $\begingroup$ @ilayda As my comment notes, I was referring to SIDs in the U.S. $\endgroup$
    – user22445
    May 20, 2023 at 18:09
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(In the U.S.) If you have already received your ATC clearance and then, while still on the ground, determine that you are unable to fly the assigned RNAV SID (due to aircraft GPS/navigation equipment problems) you should contact ATC Clearance Delivery (generally in the Tower) and advise them.

Clearance Delivery will then coordinate with the IFR controlling agency from which the clearance originated. Typically this would be an ARTCC unless it's a short range clearance within the Approach Control's airspace. Then the IFR controlling agency would provide a different clearance consistent with your capability to fly it.

It's possible that a different (conventional) SID/Departure Procedure would be assigned or a radar vector departure may be assigned.

Contacting your company dispatcher (or similar) to refile a flight plan should not be necessary under most circumstances that I can envision.


As a note for informational purposes only, here is a SID from Dallas-Fort Worth Intl (DFW) - GRABE EIGHT DEPARTURE (RNAV). It is comprised of two pages. Note that this same SID can be used for multiple runways. This, in the U.S., is very common.

PAGE 1:

enter image description here

PAGE 2:

enter image description here

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    $\begingroup$ Yep. In airline flying, we're routinely assigned a different SID than what was filed (mostly due to runway changes) and it never results in the flightplan being refiled. $\endgroup$
    – Ralph J
    May 20, 2023 at 18:09
  • $\begingroup$ @RalphJ And,as I'm sure you have noticed, most SIDs in the U.S. serve more than one runway. But this doesn't mean that a runway change might not cause a different SID to be assigned for other traffic flow reasons. $\endgroup$
    – user22445
    May 20, 2023 at 19:14
  • $\begingroup$ Many airports have one set of departures that are used when on a "north flow" and a different set used when on a "south flow" (i.e. departing the 35's vs the 17's, for instance). So when the airport gets 'turned around' then instead of the NNNNN.FIXXX you get assigned the SSSSS.FIXXX (where NNNNN & SSSSS are different departure names, but the first enroute FIXXX is the same). Not all airports do this, but enough that it's common to see. $\endgroup$
    – Ralph J
    May 20, 2023 at 20:30
  • $\begingroup$ @RalphJ I don't disagree. My comment to one of the answers above was to highlight that U.S SIDs are not runway dependent as a naming convention. Because of traffic flow requirements (turning the airport around for example) you could be assigned a different SID. Unlike many airports in Europe, for example, most U.S SIDs will use the same SID for different runways, just a different route (sometimes different alt restrictions and transition names) depending on the runway used. PHX, DFW, ATL, etc. as examples. $\endgroup$
    – user22445
    May 20, 2023 at 20:44

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