"Bob Gardner" wrote in message ...
The reason that VDPs were developed is (as always) because of an accident. A flight crew mistakenly
identified the lights of a carnival with the runway environment and descended early...into terrain. There is
no excuse, no loophole, for descending early....the consequences might be tragic. If you fly the approach as
if no VDP is provided, you will maintain the MDA until you either pick up the runway visually or reach the
MAP. In any case, in murky conditions pilots should stay about 50 feet above touchdown zone elevation until
they see the green lights pass beneath the aircraft (Gardner's Rule of Longevity).


Excellent article about that currently at avweb...

http://www.avweb.com/news/columns/188394-1.html

Cheers,
John Clonts
Temple, Texas
N7NZ