En route glide slope?

Icebound wrote:

Uh... Stefan..., a look at the altimeter provides you with *indicated*
altitude. It only shows *pressure* altitude if the altimeter setting is set
to 29.92

Uh... Icebound..., the altimeter *always* indicates pressure altitude.
To get useful information, you must set the altimeter appropriately, of
course. Appropriately may or may not mean 1013.

On the other hand, your GPS always gives you GPS altitude, which is of
no value in flight.

Stefan