Good Question Silvio, The answer is probably related to an accident
in the early 70's. A Piper Aerostar hit the ground with both fuel
selectors in crossfeed. I have no idea why he crashed, but the selctor
situation came out in the litigation, and some folks seemed to think it
was Piper's fault. This was during a time when Piper aircraft was about
to become "the new piper aircraft". I tried to check the NTSB reports,
but they only go back to 83 or so. Maybe someone here can remember
better than I. Al