In the late 1970s/early 1980s the RAF began replacing the old metal spar blades of the Puma HC1 with brand new, composite items. We were shown photos of these chopping down telegraph poles etc which really impressed us.
A couple of years later it was discovered that a faulty batch of carbon fibre had been used on some blades and guess who had bought them?
An NDT rig was sent out to Germany. It consisted of a jig with a hydraulic ram to deflect the centre of the blade. Sonic transducers were attached to the blade under test. The idea was that how much it "creaked" determined how good (or bad) the blade was. We were walking across the hangar to morning brief as the first "non destructive" test was being carried out. There was a loud "BANG" and the blade snapped!
We weren't impressed after that.
