Originally Posted by
tdracer
if that's how the system normally works, it would require a pretty detailed terrain map to reliably determine altitude to the local ground level.
In which case all that needs to be done is align the GPS '0' to the same reference zero that has been in use since forever to calculate elevations and altitudes for the standard old-school aviation data-set? Within the original scope of the thread - not it's the altitude which was wrong already, no need to evaluate height.
My personal favourite is to mandate the ANSPs to publish radio-height at the 1000' AAL checkpoint for every IAP. Darn easy, GPWS, EGPWS and ACAS also started mandatory for big aeroplanes only. I mean, if the issue is flying into terrain and RAs exist, why insist on devising another tool or gadget instead of learning how to utilize the full potential of what we already have?
For the aeroplane discussed, an electronic comparison cross-check between FCU BARO REF and MCDU APPR PG seems a no-brainer.