Whenever I watch the routes of aircraft flying between BIKF (Keflavik, Iceland) and e.g. EGLL (Heathrow, UK), they make a small turn in between to avoid oceanic airspace. See for example this flight route:

British Airways flight EGLL-BIKF 04JAN20

(Source: Screenshot of https://www.flightradar24.com/data/flights/ba894#236858ea)

The turn is made at the point where Shanwick Oceanic, Reykjavik FIR and UK airspace border each other. A direct routing would have a segment of around 220NM in Shanwick Oceanic airspace.

What's the reason, these flights don't go through Oceanic airspace? I observed that it's operator independent (ICE, BAW, EZY all fly this dented route) and it doesn't correlate with aircraft capabilities (ICE flies the same airctaft through Gander Oceanic on the way to North America all the time). So why is this routing?

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    $\begingroup$ Oceanic, you say? Remember what happened to Oceanic 815... $\endgroup$ Jan 6 '20 at 1:57
  • $\begingroup$ When in doubt: fly over land. $\endgroup$
    – Mast
    Jan 6 '20 at 7:51
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    $\begingroup$ @Mast "Oceanic" here means who controls the airspace, not literally flying over land vs. over water. They're flying over water either way. $\endgroup$
    – reirab
    Jan 6 '20 at 16:51
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    $\begingroup$ Interestingly, based on the answer below it seems it can be summed up as "Because stupid." ie in this modern high tech age we are artiificially routing to meet some semi-random paper requirement. || In 2003 I flew London-Bangkok on QANTAS. Rather than taking the obvious route across Iran, we flew to the north of Iran parallel to the border and then turned slightly 'right' thus avoiding entering Iranian airspace. I imagine that that would be still be being done at this immediate moment :-(. $\endgroup$ Jan 6 '20 at 19:25

I don't think they are specifically avoiding Shanwick Oceanic airspace. The reason seems to be related to the airways in the Scottish airspace. In general, you have to file a route using airways when operating in this airspace and there simply isn't one available that provides a more direct route. I recreated what looks like the route you show on skyvector.com:


This route would use UL612 between DCS (Dean Cross) and STN (Stornoway) and then continues via the N610 to RATSU, which marks the border between Scottish, Shanwick Oceanic and Reykjavik airspace. There are no airways from RATSU in the Reykjavik airspace, so they probably filed a direct route from there. The total length of this route would 1049 NM.

You can see alternative airways to use in this zoom (or go to skyvector.com, select "World Hi" for high altitude airways and zoom in):

Scottish Airways

There are two waypoints South of RATSU where one could enter Shanwick Oceanic airspace: ATSIX and BALIX. The shortest routes I could find with skyvector were 1042 NM and 1035 NM long respectively. This is basically the same distance and the optimal route would likely depend on the current winds.

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    $\begingroup$ I feel like the important part of your answer is “you have to file a flight plan using airways when operating in this airspace” which I wasn’t aware of, I thought it’s possible to use DCT routings between BIKF and EGLL (or the respective STAR and SID fixes) $\endgroup$
    – Florian
    Jan 5 '20 at 14:10
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    $\begingroup$ It is sometimes possible to file DCT segments, but this might get rejected when validating the flight plan with Eurocontrol. $\endgroup$
    – Bianfable
    Jan 5 '20 at 14:12
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    $\begingroup$ @Florian Generally speaking, you must always file along airways, unless the airspace in question has implemented Free Route Airspace $\endgroup$ Jan 5 '20 at 16:38
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    $\begingroup$ Fair enough, but this invites the follow-on question: why isn't there a more direct airway? Surely the waypoints exist to serve flight needs, not vice versa. Or perhaps this route actually is quite direct on a great circle? and only appears especially dog-legged on this projection? $\endgroup$ Jan 6 '20 at 4:57
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    $\begingroup$ @SwissFrank The projection won't add a dog leg, but the great arc path isn't too far off of this path. The great arc path from LHR to KEF is 1,025 nmi, only 24 nmi shorter than this path. They probably simply figured that it's not worth adding complexity to the oceanic airspace system and reducing flexibility for the North Atlantic Tracks just to save 20-25 nmi on flights to Iceland. $\endgroup$
    – reirab
    Jan 6 '20 at 16:58

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