We don't encounter the "jet dump" very often anymore on engine/tankers but at one time there were fairly popular. The proliferation of the Newton 10-inch square dump valve really changed "the game" as they say in the world of dumping water with tankers. What we have encountered on at least three occasions over the last decade are fire departments taking possession of a "used" engine/tanker and not knowing that it has a jet dump feature. In all three cases, a 5-minute tutorial on how to use the system left the folks in better shape in terms of off-loading their water in a tanker shuttle operation. The jet-dump concept certainly improved dumping operations especially when the 6-inch round dump was popular.