ORIGINAL: Whirley Bird
Hi Ed,
I friend who used to fly the big 747 called them leading edge flaps.
He also told me the plane even when no passengers were on can't roll back to lift off.
I have NO idea what you mean by this. Do you mean that a 747 cannot rotate for takeoff when it's very lightly-loaded? Not so, since they DO get ferried all over the place from time-to-time with no passengers aboard. What about training flights (the few that actually do occur)? The only real requirement is to make sure the airplane is within its weight and balance limits.