If I am standing at my hangar at bk and my iPhone says 60’ I know it is accurate.
Is using Lnav plus V I check the altitude from the altimeter with the distance on the Gps to the next waypoint and check with the instrument plate.
But I let the autopilot fly the approach. Less workload. Less errors.
Are you suggesting that Garmin and Cessna have not thought out the +V approaches?
Can you tell me more about the iPhone SBAS Australian trials? Or is it a furphy ?