Having been in the airline/military at the noisy end of engines for 50 odd years the worst ones were flying in MK1 Shackletons for long periods and been on ground runs of military jets the worst civilian ones were Viscount [whistle]Comet [roar]and the Tridents A.P.U .all before ear defenders were issued by BEA/BA they were in some cases too good we wore them most of the time on the aircraft stands and were more likely to be run over by a truck as we could hear very little wearing them I finished up losing the high range in my hearing and a little deaf but a pair of National Health hearing aids cures most of my problems when I remember to put the things in , old age doesn't help.