I was on my first ever flight in a Robin DR200-160, after having flown the -120 and the -135CDI, and the R2160. But all of those had a single fuselage fuel tank, while this -160 also had two ferry tanks in the inboard section of the wings. We had flown on left for a while, then on right, and the remainder of the flight was to be on the main tank. So I twist the fuel selector to, what I thought, was the "main tank" position (arrow pointing forward). As it turned out, this was the "off" position. Arrow pointing backwards was the main tank.
Isn't there some sort of certification requirement that specifies that knobs, selectors and such, to the extent possible, should have "up" or "forward" meaning "good", "fly", "go faster" and "down" or "back" meaning "bad", "stop", "land", "go slower"? Plus, if you want to do something that might be really stupid in-flight (such as shutting off the fuel completely), shouldn't there be some sort of guard so that you cannot do this by accident?
Fortunately the pilot who accompanied me spotted my error in time.
tmmorris, the PA28 does have a little guard built-in into the fuel selector so that you cannot accidently turn it off. In fact, the first time you deliberately want to turn it off (on the ground) you've got to look carefully at how to place your fingers so that you can push the guard out of the way and turn the selector at the same time. At least, this is on all the PA28s I have flown (so far the -161 model only).