It does not seem reasonable when you put it like that, but when could it be said with confidence that it only affected just one flight plan? I get the impression that it is only in hindsight that this could be seen to be so. On the face of it, this was just an ordinary transatlantic flight like thousands of others, with no reason to think there was anything unusual about it to make it more vulnerable than the rest - and really, there was not, it just had an unlucky combination of parameters.
In general, the point where a problem first becomes apparent is not a guideline to its scope.
Air traffic control is inherently a coordination problem dependent on common data, rules and procedures, which would seem to limit the degree to which subsystems can be siloed. Multiple implementations would not have helped in this case, either.
Shutting down a flight control system might have other knock-on effects on flight safety. Even if it merely only grounded flights not yet in the air, the resulting confusion might lead to manual mistakes and/or subsequent air lane congestion that might cause collisions.
I think you’re on the right track, I assume it’s safety.
If one bad flight plan came in, what are the chances other unnoticed errors may be getting through?
Given the huge danger involved with being wrong shutting down with a “stuff doesn’t add up, no confidence in safe operation” error may be the best approach.
In general, the point where a problem first becomes apparent is not a guideline to its scope.
Air traffic control is inherently a coordination problem dependent on common data, rules and procedures, which would seem to limit the degree to which subsystems can be siloed. Multiple implementations would not have helped in this case, either.