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Some years ago I have spotted that an Eurolot flight from Amsterdam to Gdansk, diverted close to final approach to a distant airport on the other side of Poland:

enter image description here

Is this another example of Flightradar24 bug and it is more than possible, that this particular flight actually landed in desired destination airport? Or are there any business or operational rules or some special situation, that would judge diverting a plane to a distant airport, while having at least 5-6 other airports closer "on the track"?

For me -- layman -- the answer is: No, there are no such reasons and airplane is always diverted to the nearest airport, that is able to accept it (taking plane type, weather conditions etc. into account). But, I'd like to get some expert confirmation, if there are no exceptions from this rule of thumb?

EDIT: In my opinion, we're dealing with a quite different situation here than in previous question (and that's why I didn't merged both questions into one). Mainly, because:

  • flight path IMHO is clearly suggesting a diversion, not an error in Flightradar24 and

  • plane's vertical speed is suggesting, that plane is actually landing in the moment, this screenshot was captured, and since I was living in Katowice for over 30 years now, I'm pretty sure, that there was not direct flight on AMS->KTW route, neither by Eurlot nor by any other airline and neither at the moment of capturing this screenshot nor right now.

So there actually was no other flight between Amsterdam and Katowice that Flightradar24 could mistakenly taken as this one.

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    $\begingroup$ I think you could have just edited your other question rather than posting a new one. $\endgroup$ – fooot Mar 29 '16 at 19:27
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    $\begingroup$ I'm voting to close this question as off-topic because it seems to be asking about a software bug in a 3rd party service. $\endgroup$ – Simon Mar 29 '16 at 19:29
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    $\begingroup$ Weather, governmental restrictions, wanting to stay out of contested airspace, military operations, political tensions, etc are all good reasons for a flight to fly longer than expected paths. The path you have in your image is not a diversion (which involves landing at an airport other than your intended destination), its more like a long-route. $\endgroup$ – Ron Beyer Mar 29 '16 at 19:37
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    $\begingroup$ Your edit does not help. So there actually was no other flight between Amsterdam and Katowice that Flightradar24 could mistakenly taken as this one. This is flawed. You assume that the bug is that it confuses 2 flights. How about "Last time we know, the aircraft was here. Now it's over there. I will draw a straight line between those 2 points". If "here" or "over there" are wrong, then the line is also wrong. I think you should ignore Flightradar24 and find alternative sources. $\endgroup$ – Simon Mar 29 '16 at 19:50
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    $\begingroup$ I've read the arguments and I still can't say that you can take any data as gospel for FR24. Perhaps FR24 thinks its near Krakow but really its closer to Gdansk. Maybe the lower part of the flight segment is the actual error and the aircraft is descending into Gdansk... $\endgroup$ – Ron Beyer Mar 29 '16 at 19:50
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The diversion airport is selected by the captain¹.

If the aircraft needs to divert for some urgent reason like engine failure, smoke/suspected fire/fire, medical emergency and similar, the captain will select the airport so that they can land as soon as possible. However from cruise altitude even expedient descent still takes about 15–30 minutes and the plane can cover 50–100 nmi, so they still have some choice in most places, especially densely populated areas like Europe.

But there are many less urgent reasons that warrant diversion. The most common is of course that the intended destination is closed due to weather, accident or other problem. And then there are problems like pressurization failure that require descent to lower altitude where the fuel consumption is higher, so the plane no longer has enough fuel to reach the original destination, but still has fuel to fly considerable distance.

Sometimes the plane can even reach the intended destination just fine, but some fault occurs that would be hard to fix there, so the plane returns or diverts somewhere it will be easier to fix.

In these cases, the captain calls the airline dispatching (over radio, HF radio or satellite phone) and discusses with them where they should divert to make least disruption to the overall airline operations considering things like ability to fix the diverting plane, availability of replacement plane or alternate connections for the passengers, availability of replacement crew to fly the replacement plane or this plane after it is fixed, availability of airline representatives to take care of the passengers and many other things.

So something happened and for some operational reason it was easier for the airline if they had the plane in Krakow than if they had it in Gdansk (or, if it was not possible to have it in Gdansk, better to have it in Krakow than, say, Warsaw, which was still closer). For example I remember reading about incident where wind shield cracked on a plane already on approach to their destination, Klagenfurt, and they returned to Vienna and sent the passengers by bus. Because it was apparently easier (and cheaper) for the airline than fixing the airplane in Klagenfurt without suitable hangar (with cracked winshield the plane may complete the flight, but not take off again).


¹ Except really special circumstances like violation of foreign airspace and arrest by interceptors, nobody from outside can divert the plane. The pilots do.

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I won't reply to the "is it possible the flight was diverted this far" bit, as other have given good reasons for this.

However, even though we're missing quite a bit of data, it seems quite obvious that this specific flight was never diverted: the AMS-GDN flight got out of range of FR24 on approach to GDN, and somehow FR24 took the following flight (from GDN to somewhere else, probably Krakow) as the continuation of this flight. Full data history would probably show a big gap in the data between the two sharp "turns".

This is consistent with:

  • the times shown (ETA 9:09 PM CET, actual time 21:47 UTC which is 10:47 PM CET, well into the next flight),
  • the actual paths which are clearly aligned with GDN (both inbound and outbound),
  • the fact that the "turns" are way too sharp,
  • recent flight history for the aircraft (which flies GDN-KRK on a very regular basis)
  • the absence of any other aircraft on the map in the GDN area

Remember this is a Dash 8, which is not equipped with ADS-B, but a simpler Mode-S transponder, which requires multilateration (MLAT) and hence to be visible from at least 4 stations to show up on the FR24 map, and provides less data.

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  • $\begingroup$ Great analysis and "investigation" on FR24 stuff and possible errors. Thank you. Pity, that I can only +1, but I can't accept your answer as it does not answer question directly. Anyway, great contribution! Thank you. $\endgroup$ – trejder Apr 5 '16 at 6:16
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Is it possible to divert a plane to a distant airport?

I was on a flight that was diverted from Heathrow in the south of England to Prestwick in Scotland. It seemed like quite a long distance to me at the time.

There are actually plenty of airports closer to Heathrow than Prestwick.

This was due to major storms sweeping through the British Isles.

The plane was initially diverted to Manchester but that airport was closed before we got there. Prestwick was pretty bad but I think the pilot was probably running out of choices within fuel range by that time.

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There are lots of factors playing into a pilot's decision as to which airfield to divert to. Typically this will include:

  • Where that airline has a ground team e.g. a Easyjet flight inbound to Gatwick is unlikely to divert to Heathrow because it won't have any staff on the ground to deal with passengers, and it costs a hell of a lot to hire someone else's team!
  • What are the landing conditions at the diversion airfield e.g. if there is low visibility and fog at Charles De Gaulle, then the same weather might be present at Orly
  • The length of the runway - most passenger jets (say B737 and above) are going to be too large/heavy to be able to land at London City, so they'll choose to divert elsewhere
  • And, of course, how much fuel is left on the aircraft! Pilots will want to have enough fuel to be able to safely abort one landing, circle the airfield and try again - as an absolute bare minimum.

As for fuel minima - it varies a bit from country to country and airline to airline, but a general rule of thumb is that the flight should have enough fuel to hold in a stack for a reasonable time (20-30 minutes at Heathrow), attempt a landing, and divert to their declared alternate. So, if you're going to make the decision to divert early, then you could feasibly travel a good extra distance in pursuit of one of the items listed above.

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  • $\begingroup$ Well I'd say, that this is one of the best answers, I ever found, made by person, who has just joined the community. Thank you very much for your contribution and congratulations on a great start. $\endgroup$ – trejder Apr 5 '16 at 6:19

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