Originally Posted by
ORAC
The report, submitted earlier this week to the Civil Aviation Authority, identified an issue with a flight plan processing sub-system called Flight Plan Reception Suite Automated – Replacement (FPRSA-R).
A small but important part of NATS’ overall air traffic control technical infrastructure, it was found to have encountered an extremely rare set of circumstances presented by a flight plan that included two identically named, but separate waypoint markers outside of UK airspace.
This led to a ‘critical exception’ whereby both the primary system and its backup entered a fail-safe mode. The report details how, in these circumstances, the system could not reject the flight plan without a clear understanding of what possible impact it may have had. Nor could it be allowed through and risk presenting air traffic controllers with incorrect safety critical information. On the day, the time taken to recover was driven by the need to identify the problem and the specific data, isolate and remove it in a controlled way, and then test it to ensure it could be returned safely into operation.
This scenario had never been encountered before, with the system having previously processed more than 15 million flight plans over the 5 years it has been in service. Steps have been taken to ensure the incident cannot be repeated.