BW
Our civil brethren don't mix airworthiness with operations and training; so why the hell should we???
Not quite true at the risk of thread creep. If the paperwork isn't in place the aircraft isn't deemed 'airworthy' though it may be to all intents and purposes 'serviceable' as far as engineering and aircrew are concerned. I can recall a lot of airliners sitting on the ground one Sunday morning because current insurance certs weren't on board, they'd run out midnight the night before, yet aircraft were 'serviceable'.
Having read this thread and other external media, it appears so far, from info published in the public domain, that the issue is a human/operations primary cause, rather than a technical one. (Apols for thread creep.)