JT2, SFFP, ShyT and VP
Thank you for reminding me that NI was a truly 'operational theatre' for SH; I'd rather forgotten that (being FW AT). However, this then adds to the mix a concept of which even FW AT is now more aware.
That is; sometimes, when flying on operations one needs to bend the peacetime rules just a little - this is not recklessness just pragmatism, especially when lives of the PBI are on the line.
Of course, the real down-side to this concept is that when you get back home, you then need to 'retrain' yourself to do things by the book. This can be difficult if you have been on ops for a long time, as the boundaries can get blurred.
Failing to adjust is not negligence; it is just another 'human-factor' that needs strong and sympathetic leadership, supervision and understanding. It is certainly possible that the crew ZD576 may have been suffering from such a blurred picture when they left the operational theatre and ventured into the 'peacetime' Low-Level Flying System in western Scotland - if, indeed, they were 'pushing' the limits of VMC - however, that has never been proven.
As for the ac being perfectly sound, VP - I think you'll find that it is not that simple. There are enough well-qualified people who have voiced concerns about the FADEC and its handling to make any sane person have doubts about the integrity thereof - not least because of the in-flight checking of connections. Nonetheless, I think you may well have a valid point that illusions, perceptions and expectations go hand in hand. Lord knows I've had a few of those moments myself.
We still come back to the crux of the matter - no-one knows for sure and we never will. So why 'grossly negligent'?