Boscombe effectively grounded theirs I had hoped I would not see yet another occurrence of the safety case being over-ridden. I'm sure the ac (RJ) is probably perfectly safe, but if we have an airworthiness system - no matter how flawed as Tuc has well argued - it should not be circumvented.
I'm afraid such an over-rule is not only permitted, but as I've often said MoD and Ministers (and lately the Head of the Civil Service) have consistently ruled that it can not only be made by unqualified people, but the person who has the airworthiness delegation can be disciplined for refusing to obey an order to make a false declaration that the regs have been met.
As ever, it is the implementation of the regulations that is lacking, not necessarily the regs themselves. More recently however, it has become apparent many in the MAA don't actually understand them. Hardly a surprise given the ethos of the last 20-odd years.