FWA Mike
I hate to split hairs with a fellow seasoned professional, but in the UK, the airport authority is allowed to revise runway distances to take into account any obstruction which is either in the approach path or on the actual runway.
In the aerodrome manual there a standard set of formula, and they just insert the height of the obstruction, the original runway length and the normal glidepath, and, as if by magic, the revised runway length appears!
I've experienced it during the work to extend a runway, when contractors plant and equipment was at one end of the runway, and we landed aircraft over the top of them. The really spooky bit was when we were landing the other end, and aircraft had to stop a certain distance from the start of the WIP!
Another example, is a permanant dispalcement, which is what we have on one of our runways.
We are allowed to line aircraft up at the a holding point, which is the beginning of a take off starter extension for that runway, and then land aircraft over the top of them, who touch down some 400m further up the runway itself.
It doesn't look right from where I sit, but it's legal
