Originally Posted by
WideScreen
fdr I agree with your writing, though my issue is, that this "tool" still is the (admittedly much better) primary driver for the flight path.
What we are missing is the "independent and automated verification" of what flight path the flight crew creates/follows with the tools they have available (or should have available in the ideal situation). The verifier is the one that saves the lives, when the flight crew screws up, for whatever reason.
I get that, but say trying to fly in Paris, Bhutan, or around Mongolia, Kunming, South Korea in winter, and the error is easily greater than the 10mb in this case. Had a crew do an autoland once before they got to minima... Using PA below about FL180 is a technical backwardness. The system isn't going to change anytime soon, but in the interim, the next panel upgrade I'm doing to my jets includes space for an iPad as the EFB, and for general "SA" benefits. It already interfaces with the APFD and C145 nav systems. Geometric altitude is where there be dragons, that's the info I find nice to have on hand.
On a GPS based 3d source, if the aiming point is 3 degrees below the horizon, that is where you are going if you are flying your 3 degree path.