Mark, I really don't know the answer to that question. In school we were told that if you entered the gate position in the IRS panel itself, maybe several times, eventually the unit would accept the new position. I have seen that done with other planes and it the simulator. This 757 was a newer plane with a more up-to-date "Pegasus" system.

When we arrived at our destination, the mechanic came to the cockpit to look at what he could do. He told us that he was going to basically un-install the software and re-install it again.....

                                                               Sorta like FSX!  :o

So, just one small glitch, caused by ground personnel moving the plane improperly is not too bad for 30 years or so of INS/IRS flying. This system is so much better than anything else we had before.

Lou