Originally Posted by
FlightDetent
......
Why cannot we yet, pretty please, get a rough GPS-alt vs. Baro-alt comparator for gross errors? In a form of "CHECK QNH REFERENCE" ??? Come on, it's 2022!
I am glad, you raise this item. This event (and many, many others) do scream for an E2GPWS or EGPWS-NG, or what-ever. GPWS is a kind of static virtual 2-D vs. height "where am I". EGPWS effectively creates a dynamic multidimensional "virtual-path", where it is safe to fly. The E2GPWS would add the GPS version of the approaches, down to acceptable Terra-Tarmac-Touchdown-Zones, and produce warnings, when the factual GPS flight path goes outside that "cone" (low/high/left/right). The closer the airplane gets to the GPS ground, the smaller the cone size will be.
Of course, there are a lot of "but's", though such a feature working properly, would (have) save(d) quite a few potential and real mishaps. This would be relevant, not only for this case, though 2 times the near accident with an A380 (Moscow/New York), the ACT/Bishkek, the PIA touch-and-go on engine pods at Karachi, all the Asian water touch-downs just short of the runway, and a lot more. Not to say, it gives quite a solid checkmark for being stable at 1000 ft (or at least in the approach cone).