Just about everything that made the Royal Air Force the professionally excellent, technically superb, service that it used to be. Then the MOD (and the Air Marshals) set about sabotaging all that by ridding itself of such folk. They were replaced by administrators and suppliers (ie beancounters) and the UK Military Airworthiness Regulations were systematically and routinely suborned thereafter. The result:
Mull 29 killed, Hercules 10 killed, Nimrod 14 killed. Those just for starters. That was what was so special about them Aeronut, the effect that their absence had.