Having not long ago returned from RHC maintenance course it was highlighted that the -4 blades skins (stainless) are now only a third the thickness of earlier (aluminium) blades. (.008 -v- .025 thou).
This reduction in skin thickness is very evident in the markedly differing (less tolerant) damage limits with the new blades. A bit of 'Hangar rash' is now enough to render a blade scrap. Be careful and treat them with respect. RHC reported they are doing good trade in MR blade sales due to carelessness.
