Today I was once again on Reagan's Air Force 1, and in the cockpit, to the left of the flight engineer's seat, is a box labeled "Flight Data Recorder". It has several numbers to punch-in, including Day, Month, and Take-Off Weight. I don't remember the others, but my question is:
Why would they have to enter the Take-Off Weight into the FDR? Is that done in modern aircraft as well? What happens if the number entered is not correct (Either way, under, or overweight)?
Any info appreciated.