Fuel dumping
I can remember ( I think) that BAH S61's or some of them had fuel dump back in the 70's. The limitations on its use were a favourite trappers question. The only one I can remember was "Do not transmit on HF while dumping"
The only time I came close to using it was on one occasion I was en route to an unlimited deck so was planning to land at 20500 (or whatever the WAT figure for the day was) and was asked to divert to a limited deck rig that was en route, max landing weight limited to 19000lbs, for a casevac and back to shore.