I have once. It was an America West Express flight from PHX
on a CRJ-900. I noticed the engine cowlings open when I got to the gate about 2.5 hours before the flight (early, I know). But it seemed they took care of it, and we boarded and taxiied (for a long time) to 7L
. Just as we were second in line for t/o, we exited the taxi line and went back to the terminal because of some faulty oil pressure indicator. At first they told us to wait on the plane, but just five minutes later we were put back in the terminal. At first we were supposed to wait out repairs, but then they decided to bring in a new plane. Sometimes this takes a long time, but fortunately we were in PHX
so other planes were available on the premises, and about an hour and a half later we were on our way. To re-board, we had to either use our boarding pass stubs or our IDs, which were checked against a manifest and crossed off as each person boarded. As we taxiied out again, we went past our old plane, still being worked on.