Recently, John Kulp posted:

On Wed, 31 Oct 2007 14:07:55 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote:

John Kulp wrote:
On Wed, 31 Oct 2007 11:34:47 -0600, Newps
wrote:




John, you seem to be under the impression that GPS is going to
somehow manage to change the physics of time and space. Yes, when
airlines use GPS they can fly direct from point A to point B but if
A and B are crowded they are still going to have to wait on the
ground to take off and fly around in circles waiting to land.

Where did I say this? I said that if spacing can be reduced due to
safer wake turbulence management then GPS can be used to safely close
those spaces and improve the capacity of the system. That's all.
Just where do you think I am confused. And, if I am wrong (or
confused)

From what you said on 10/29/07:

"Gates can be a problem sometime but not runways. The GPS system would
handle about 25% more flights on the same runways."

And restated in your response to Jim:

"So you are saying, at peak rush times, there is 25% extra time for
separation to be maintained?"
--
Jim in NC


"GPS allows for closer spacing and straighter flight paths allowing
more flights to be handled in the same time span. About 25% more."

It appears that your expectations are too optimistic. The reasons for the
required separation in the destination airspace are wake turbulence and
runway safety. GPS will not have an impact on that, and that is where and
why the delays are occurring. As several others have explained, getting
there faster will not mean getting on (or off) the ground faster. It may
be that having 25% more flights in the air would only aggravate the
situation, as the required separation would still have to be maintained in
the airport's environment.

a. why is the FAA going ahead with the building of the system?

b. why are the airlines backing that change?

There are some benefits to upgrading the technology, particularly in
regard to near-misses en route. But, as long as the airlines' scheduling
and hub system are unchanged, there probably won't be any big improvement
in the number of delays. Go to one of the busier airports and observe the
arrivals and departures and you'll get an idea of why.

Neil