GFZ90:
This implies that whilst the control becomes very limited if a FADEC fails, and the affected engine should be shut down for landing, it is not in itself necessarily a catastrophic hazard.
AFAIK this FADEC design was unique in that if it failed there was no manual reversion. It was also very prone to failure in that, as tuc has reminded us, an audit of its code was abandoned as the amount of mal-coding was too large to complete economically. It could not even be relied on to go into reversionary mode following failure, as the number of uncommanded power ups, downs, and shutdowns testify. It was, in short, so bad that Boscombe Down pleaded that the RAF ground the Mk2 (which was already in squadron service thanks to the creative use of the RTS system). I don't know what your motivation is to try to characterise the FADEC/DECU problems as a storm in a teacup, but for my money it was Gross Negligence by the MOD that this aircraft entered RAF Service in this state, let alone to be tasked for VVIP transport over the express protests of the Detachment Commander.