Those involved in planning see it differently. That is why the new RNAV
(RNP) criteria presumes a failure of GPS during a terrain-critical phase
of flight.


Is that because of the physics and architecture of the GPS/WAAS system or
is it because the system is still new and not yet proven through enough
testing and actual flight experience?

It's because the known failure rate is considerably higher than with
either VOR or ILS.

Really? Where did you get that data? Show us your source.




A long history of FAA ground-based nav aids has shown very, very little
problem with the ground components of the system. And, where it occurs
there is usually an alternate nav aid or aids available.


It seems you missed the point. The original point was that the chance of
a failure of GPS is not a rationale for preferring ground based navaids
because ground based navaids can fail as well. No one said or implied
that ground based navaids have a high probability of failure.

If I missed the point then you didn't do a very good job of making that
point.

ted wrote:
Sorry, my intended audience was people who could read english.

wrote
I thought we were having a reasonable technical discussion. Instead, you
are another Usenet droid asshole.

Sorry if I hurt your feelings.

If you are truly interested in a technical discussion then why didn't you
answer the question above? where did you get that data?