UK air traffic control outage caused by bad data in flight plan
1–10 of 22 posts
Re: UK air traffic control outage caused by bad data in flight plan
#2"Nats said the failure was due to “an extremely rare set of circumstances” with two identically named but separate waypoint markers outsidethe UK’s airspace "
Sounds like a fairly common error case to check for although they say that it never happened before.
ID collisions are always something to check for, not least when the data are user inputs.
Re: UK air traffic control outage caused by bad data in flight plan
#3" Nats said the failure was due to “an extremely rare set of circumstances” with two identically named but separate waypoint markers outsidethe UK’s airspace " Sounds like a fairly common error case to check for although they say that it never happened before. ID collisions are always something to check for, not least when the data are user inputs.
[deleted]
Re: UK air traffic control outage caused by bad data in flight plan
#4" Nats said the failure was due to “an extremely rare set of circumstances” with two identically named but separate waypoint markers outsidethe UK’s airspace " Sounds like a fairly common error case to check for although they say that it never happened before. ID collisions are always something to check for, not least when the data are user inputs.
And checking for ID collisions is generally extremely easy, both in code and compute.
And the ID collision was in user data which the air traffic system has to continuously accept during operations.
And it sounds like that data breaks down into individual flight plans - so it might be trivial to reject just one flight plan, and allow the rest to proceed.
BUT...doubtless the UK's flight control software came out of some multi-billion-pound government boondoggle. So we should be grateful that it doesn't crash planes into each other, or send innocent postal workers to jail for theft, and overlook these sorts of failures.
Re: UK air traffic control outage caused by bad data in flight plan
#5If there's two waypoint markers that are named the same, how did the flight control and/or plane software know which one is being referred? Assuming closest, it would have had to special case for it already, no?
e.g. if I want to drive to Springfield, it needs to know which one out of 67 I'd like to go to...
Re: UK air traffic control outage caused by bad data in flight plan
#6" Nats said the failure was due to “an extremely rare set of circumstances” with two identically named but separate waypoint markers outsidethe UK’s airspace " Sounds like a fairly common error case to check for although they say that it never happened before. ID collisions are always something to check for, not least when the data are user inputs.
And checking for ID collisions is generally extremely easy, both in code and compute. And the ID collision was in user data which the air traffic system has to continuously accept during operations. And it sounds like that data breaks down into individual flight plans - so it might be trivial to reject just one flight plan, and allow the rest to proceed. BUT...doubtless the UK's flight control software came out of so…
"reject just one flight plan, and allow the rest to proceed."
rejecting a plan wouldn't necessarily mean it doesn't exist/take off anymore, so that doesn't sound sensible
Re: UK air traffic control outage caused by bad data in flight plan
#7Earlier quoted context omitted.
And checking for ID collisions is generally extremely easy, both in code and compute. And the ID collision was in user data which the air traffic system has to continuously accept during operations. And it sounds like that data breaks down into individual flight plans - so it might be trivial to reject just one flight plan, and allow the rest to proceed. BUT...doubtless the UK's flight control software came out of so…
"reject just one flight plan, and allow the rest to proceed." rejecting a plan wouldn't necessarily mean it doesn't exist/take off anymore, so that doesn't sound sensible
I admit I have no idea how the system works but if there is an obligation to submit a flight plan in advance then there should also be a standard procedure not to let planes take off or enter airspace if they don't. At the very least there should indeed be a procedure to reject the flight plan even if flight cannot be stopped.
Re: UK air traffic control outage caused by bad data in flight plan
#8Having read the actual report... insufficiently rigorous validation of inputs leads to discovery of corner case.
They could have probably found this sooner with either fuzzing or perhaps some sort of digital twin model.
Finally, there's no exit clause to reject a flight plan from an "upstream"? That is a worry.
Re: UK air traffic control outage caused by bad data in flight plan
#9Link to the report from NATS (PDF) https://publicapps.caa.co.uk/docs/33/NERL%20Major%20Incident...
Re: UK air traffic control outage caused by bad data in flight plan
#10Earlier quoted context omitted.
And checking for ID collisions is generally extremely easy, both in code and compute. And the ID collision was in user data which the air traffic system has to continuously accept during operations. And it sounds like that data breaks down into individual flight plans - so it might be trivial to reject just one flight plan, and allow the rest to proceed. BUT...doubtless the UK's flight control software came out of so…
"reject just one flight plan, and allow the rest to proceed." rejecting a plan wouldn't necessarily mean it doesn't exist/take off anymore, so that doesn't sound sensible
Flight delays / cancellations / diversions (due to mechanical problems, weather, etc.) are a very regular thing - the airlines, ground crews, commercial pilots, and control towers have lots of experience with "Flight 1234 won't be taking off..." and "Flight 2345 is being diverted to...".
Or, if it's a "Bob owns a Cessna, and took off anyway" situation - well, Bob's license to fly a private airplane will probably be taken away. Maybe his Cessna, too. And (post-9/11) Bob could be spending some time in uncomfy little rooms with bars on the windows.