I have found GPS altitude to be higher than baro on hot days (above std temp 15C at sea level) and less than baro on cold days. I would bet GPS altitude is more accurate than baro but fly the baro because we all do that. at std temp at sea level and std lapse rate baro and GPS are very close. don't recommend doing this, but if you're in a bind and have to fly an approach using GPS altitude on the a hot day, fly it higher than you would on a cold day.
RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 600+ for all
Simplicity is the art in design.
Last edited by Steve Melton : 09-16-2016 at 07:23 PM.