Will wrote:


Once the pilot is in an emergency condition, how do you figure that the
pilot is better off following a GPS trace in complete ignorance of the fact
that it is inaccurate by thousands of feet? Since when is (optional)
knowledge a bad thing?

With a properly mounted attenna and a check of satellite geometry, that
simply is not going to happen with a good handheld, such as the Garmin
296/396.

I have hundreds of hours using the 195/295/296 in aviation, automotive,
and marine modes and have never, ever seen significant degragation of
accuracy when the antenna has a good view of the sky.

I have seen very poor solutions, however, when using it through a cabin
window of an airliner. I have also seen very good accuracy in that
circumstance, depending upon available satellite geometry.

Finally, as I said before, an accuracy check with DME in a light
aircraft can provide a great, short term, accuracy and integrity check
for a handheld, albeit now as good as approach RAIM.

Also, the later Garmin 500 series as fault detection exclusion, which
makes them certified for sole-source oceanic IFR. Were you aware of that?