5Z wrote:

The Garmin only logs GPS altitude. Take a look at most OLC flights and
there are two altitude lines. One is GPS and the other is pressure.
The GPS (black) one is almost always several hundred feet higher.

What "the" Garmin does in your case I leave to you to determine. My
Garmin GPSMAP 76S logs baro altitude (green line) unless I turn the
altimeter function "off", and then it logs GPS altitude (black line).
That's the way it shows on the OLC pages, and it corresponds to the way
I set it up. Normally I just let it use baro, though. It does not show
both, only one or the other.

The real loggers (IGC approved = expensive) all seem to record both baro
and GPS altitude (green and black lines) for the OLC charts.

What the 76S is actually doing inside I don't know, and I don't care.
Class A altitude busts are the least of my worries: I fly in IL where
the state freaking record for altitude is ~16,000 damn feet.

It's still raining.


Jack