Apparently, today was not a good day to be traveilling by plane in the UK. But what on earth where they thinking? Doing tests on a live system? Any IT professional worth his salt would tell you this is playing with fire. If you want to do tests, have a test system, that's what they're for. An organisation like NATS should have test systems that mirror the live ones and on which they can perform tests. If they don't, it is gross negligence.