The crux of the case was whether or not the pilot suffered Cognitive Impairment whilst flying-as alluded to by the defence. Because no one could prove either way he did or he didn't he was acquitted. If on the other hand the jury had decided that he probably didn't suffer from CI (No previous medical history, no evidence he did, RAF expert saying not) then the prospect of conviction (due to the flying involved) would have been reasonable.
I'm sorry, the public would have been outraged if no charges had been brought in the circumstances. AH has answered these charges, and was acquitted fair and square.