I'm guessing it was snuck in with the Sinai update, Prickly Hedgehog mentioned it during his Sitrep so I went and tested it and it has indeed been updated.
New engine sounds including whistling and the fixed/new keybinds are working for me, it sounds fantastic now, very handy having trim reset and autopilot.
That doesn't mean we shouldn't have the option, and there are plenty of other knobs that could be assigned. The Huey, Kiowa and Gazelle are glaring examples of this oversight.