Very few machines have a fuel jettison capability, and almost all of them are military in origin. I'm discounting the jettisoning of external tanks, more the plumbing to an external pipe.
As SS says the Sea King has a fuel jettison via a pipe above the tailwheel, which in the original HAS1 (ASW) machine was a smallish diameter with a low flow rate. It was, however, about the same diameter as the arrestor hook on the Bucc. Cue a wind up when Bucc driver chum casually asked what the pipe was for when we were mid Atlantic flying non diversion ops from Eagle.
"That's the mount for our hook when non diversion flying in case we have to make a single engine running landing"
It took 4 hours before the unrelated Sea Vixen drivers were asking when we would be fitting our hooks
