3 ms·
> Given that the system could not reconcile the error, the fail-safe software logic intervened to prevent the incorrect data being passed to air traffic control
by zarzavat 3y ago
> Given that the system could not reconcile the error, the fail-safe software logic intervened to prevent the incorrect data being passed to air traffic controllers, and the FPRSA-R primary system – as designed – suspended its functioning and handed its tasks to a back-up system. But the back-up system applied the same logic to the flightplan, with the same result, and similarly suspended itself.
This seems to be the root cause. My reading of this is that the system initially validated the flight plan, but while processing the plan it hit something it didn’t understand. It should have treated this as a late validation error, rejected the plan and continued its work, but instead it treated it as an internal error and crashed. I guess it probably hit some kind of assertion.
- panki27 3y agoIt's explained in the article. Two waypoints had identical designators, which is an edge case not implemented in the software - not sure how this is a "late validation error" if the data is in fact valid. The root cause to me seems to be that whatever they are using as designators (possibly strings shudder) is not guaranteed to be unique.
- mst 3y agoI believe when OP said 'treated this as a late validation error', they were acknowledging the inevitability of bugs and root cause-ing "why did a single failure to validate cause the entire system to fall over rather than reject the single flight plan in question." The words 'treated this as' are load bearing here.