Not exactly statistically significant, but on my own course at BFTS (old system circa 80s) there were 6 of us, one vw'd, the rest all completed training & became operational, not necessarily FJ but on something. So a long way from 90% failure, but perhaps the 10% figure is referring to the FJ stream only?
Whilst RAF training has been cut back significantly in recent years & is no longer 'training for excellence' I do believe that the original hypothesis
Is RAF training all it's cracked up to be...?
is overly pessimistic.