"Kev" wrote:


Mxsmanic wrote:
Marco Leon writes:
I thought the primary factor in determining the differences between
baro altitude and GPS altitude was the difference between "sea level"
and the WGS84 datum plane at the particular location?

In theory, yes. But in practice there is also a lot of inaccuracy in
altitude readings via GPS. The system is not designed to provide
highly accurate altitude, [..]

And a simple Google search with "gps altitude accuracy" will bring up
quite a few interesting write-ups on the topic. All urge extreme
caution about trying to use GPS as an altimeter.

Kev


Altitude accuracy is not as good as horizontal for reasons already
mentioned...not because of a design issue. It is not the accepted
form of altitude information because baro inputs do that. However, it
can be an indicator if somehow a pilot lost all altitude information.

Ron Lee