RT
Heli ops are unavoidable, there operation's are under strict health and safety scrutiny with various ear protection required.
Passengers getting on and off heli's are offered ear plugs. A turbo prop in reverse from a few metres away is at least as loud - painfully so. These pax don't have ear plugs, nor should they. Heli ops are a vital necessity - powerbacks certainly are not ! So why cause damage when it can be prevented ???
W. Bin