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UK air traffic control outage caused by bad data in flight plan

theguardian.com

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Re: UK air traffic control outage caused by bad data in flight plan

#11

Post by jebarker »

mytailorisrich wrote: post #7
robjampar wrote: post #6

Earlier quoted context omitted.

"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.

> "not to let planes ... enter airspace"

How?

Re: UK air traffic control outage caused by bad data in flight plan

#12

Post by matthewmacleod »

bell-cot wrote: post #4
mytailorisrich wrote: post #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.

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…

I have no doubt that there are huge numbers of issues with many large-scale IT projects, but this sort of cynical and hyperbolic armchair analysis makes it even harder to have rational conversations that help prevent systems failures in the future.

Consider reading the actual initial Nats report https://publicapps.caa.co.uk/docs/33/NERL%20Major%20Incident... – this provides a bunch of interesting analysis and technical information.

I'm sorry for being mean about it, but it's a personal bugbear of mine when complex systems failures are boiled down to lazy analysis.

Re: UK air traffic control outage caused by bad data in flight plan

#13

Post by cameronh90 »

bell-cot wrote: post #4
mytailorisrich wrote: post #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.

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…

Most bugs are pretty easy to solve once you know they're there.

It's all well and good to say that software just shouldn't have bugs, but that's pretty much an unsolved problem at this point. The NATS system has a relatively good track record, and even companies with exemplary engineering standards have occasionally had large system failures.

Let he who is without sin cast the first stone.

Re: UK air traffic control outage caused by bad data in flight plan

#14

Post by Scoring6931 »

bell-cot wrote: post #4
mytailorisrich wrote: post #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.

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…

With regards to postal workers: https://www.bbc.com/news/business-56718036

Re: UK air traffic control outage caused by bad data in flight plan

#15

Post by Scoring6931 »

jebarker wrote: post #11
mytailorisrich wrote: post #7

Earlier quoted context omitted.

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.

> "not to let planes ... enter airspace" How?

Airspaces are already a thing in aviation, and pilots need to seek permission to transit between them. This is done by making the request to air controllers via radio.

https://skybrary.aero/articles/classification-airspace

Re: UK air traffic control outage caused by bad data in flight plan

#16

Post by gbil »

bell-cot wrote: post #10
robjampar wrote: post #6

Earlier quoted context omitted.

"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 t…

To add, my personal experience from the air force is that flight plan rejection from Eurocontrol was business-as-usual situation so I'm also confused reading that the system instead of rejecting that one problematic plan, threw a white-towel

Re: UK air traffic control outage caused by bad data in flight plan

#17

Post by jebarker »

Scoring6931 wrote: post #15
jebarker wrote: post #11

Earlier quoted context omitted.

> "not to let planes ... enter airspace" How?

Airspaces are already a thing in aviation, and pilots need to seek permission to transit between them. This is done by making the request to air controllers via radio. https://skybrary.aero/articles/classification-airspace

I was interpreting "not let" to mean you would actually stop them entering. You're right, the parent post probably meant "deny permission to enter".

Re: UK air traffic control outage caused by bad data in flight plan

#18

Post by speg »

My current project involves processing flight plans. I believe the company even helped build part of NATS. There must be something else going on to crash the whole system.

We get so many invalid flight plans from third parties (e.g., ForeFlight) that the system would never be up if we didn’t mark them as invalid and move on to the next.

Re: UK air traffic control outage caused by bad data in flight plan

#19

Post by darkclouds »

mytailorisrich wrote: post #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.

It may well have happened before, but things like updates to new versions of a language, use of updated libraries, and other things which typically creep into new versions of programming languages to minimise bugs inevitably introduce bugs because they dont have a unit/component test to flag these things up. It also suggests different programmers have worked on the system.
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