Many years ago a USCG HO3S was dispatched to a sinking shrimp boat in the GOM. On the first winching operation a blade severed a mast guy cable. Upon returning to base to deposit the two shrimpers they inspected the blade and found a small indentation on the leading edge. They worked the area with crocus cloth per the maintenance manual and returned to the shrimp boat two more times. Upon shut down the damage blade exhibited a crack that ran from the leading edge to the rear of the spar.
They cut that area out and sent it to Sikorsky with their thanks for the robustness of the blade design.
Then there was the AB205 that landed and the entire rotor system fell off but that’s another story.
