"Marc Ramsey" wrote in message
. com...
Paul Bart wrote:
However given the assertion that the pressure altitude can differ
by as much as 1000ft from the geometric altitude, does it imply that two
pressure altitudes can actually differ by 2000ft? Would it not provide
sufficient argument to switch to geometric altitude?

Yes, this is correct. You don't have to climb as high on a cold winter
day, as you would on a hot summer day, to obtain a specific pressure
altitude gain. But, I suspect some (maybe most?) would say that we have
always measured pressure altitude is this sport, and that we should
continue doing so...

Marc

Hi Marc

Thanks for your reply. Given the budding status of my gliding career, this
is not likely to be an issue for me any time soon , however given that GPS
can *potentially* reduce an error, by up to 1000 ft it should be seriously
considered. I wonder if the resistance to change is mainly due to the high
average age of the gliding fraternity?

Paul