Did the OP have a question in it?
Test guys generate numbers and then the regulators increase those numbers by X% for line operations.
Following the GS electronically, or with PAPI/VASI with your eyes, to a 1500' aimpoint doesn't equate to a 1500' touchdown. Eye height, pitch attitude, distance from pilot's eye to main gear, etc, results in a touchdown point that is different(short) from the aimpoint.
Last edited by misd-agin; 4th Dec 2011 at 14:38.
Reason: additional text