I was told some cracks had been found on an A model "in the pacific rim" recently. The aircraft in question at some point had been in an incident involving high wind (I know laid myself wide open there
) and Sikorsky were attributing the cracks to that incident. Apparently the A model head is thinner than the B and I assume the C's.
The head is to be inspected by an engineer before every flight, unless the head has had an NDT test done on it.