Why NAS failed last week.

[NotAllThere]

https://publicapps.caa.co.uk/docs/33...y%20Report.pdf

Interesting reading.

[ladymuck]

NATS, you mean

[NotAllThere]

To be specific FPRSA-R. NAS is the bit that comes after.

[cojak]

Considering UK airspace is the most expensive in the world, I’m not surprised that airlines are p1ssed at the meagre 4hours of backup flight data.

I recognise the arrogance of senior management not understanding the the difference between proactive problem management and reactive incident management*, their Hazard Identification and Risk Management team must be as weak as dish water.

*I’m sure they do now though…

[Lance]

the system functioned as deigned.

However...
The requirements failed to identify a specific scenario that should be able to be resolved by the system. Therefore the system failed safe (as per the design).

Nothing more here than an expensive lesson learned with regards to scenarios that probably should have been considered.

[vetran]

oh dear so they have duplicate waypoints , bet that was designed a consultant - muppets.

[Gibbon]

oh dear so they have duplicate waypoints , bet that was designed a consultant - muppets.

NATS don't allocate WPs they are overlaps from different standards that haven't yet been ironed out yet. Their 'fault' was not thinking deep enough about the ramifications and allowing a single unresolvable FP (not erroneous) disrupt a whole system. Failure of resilience, which real Safety Critical systems are full of of, i.e. a system stop is a FAILURE. Think Jet engines.

[cojak]

I am actually surprised about this, as I worked for an aerospace company and have spent a good few days in Hazard Identification workshops going through scenarios with a fine tooth comb (I was the ITIL rep).

Really, they must be crap at this.

[GJABS]

Their 'fault' was not thinking deep enough about the ramifications and allowing a single unresolvable FP (not erroneous) disrupt a whole system.

I wouldn't say the concept of a single flight plan failing for -some- reason requires particularly deep thought. On the face of it they ought to have designed the system to raise an alarm if a flight plan is rejected in an non-resolvable way immediately, and skip over to process the next flight plans. This would require a robust procedure to guarantee that the failed flight plan receives manual intervention. But dealing with manual intervention issues is nothing new to air traffic controllers (for example in their dealing with aircraft declaring emergencies). test

[GJABS]

Oh the irony. When I submitted my reply above, I got an error from CUK:
Invalid SQL: DELETE FROM cuk_cacheevent WHERE `event` IN ('nodeChg_4273261','nodeChg_4273064','nodeChg_19', 'nodeChg_16','nodeChg_2','nodeChg_1') /**cacheevent**/;
But we can be sure this error won't prevent subsequent posts from being made on here.