Originally Posted by
A30yoyo
My question is: 'Is the stack separation( raised to 1000ft in 1948) still sufficient for airliners up to 8x the weight, 2x the linear size and with a stacking speed maybe 50% higher?
In keeping with the rest of your post, if you want to know how risky someting is, ask an insurance underwriter.
AFAIK there is no record of the insurance industry having declined to cover airlines who use the standard 1000' hold separation, so I think it's reasonable to conclude that it's not considered to be particularly risky.
And in the UK at least, aircraft in the hold don't use local pressure settings (QFE/QNH) so the issue of incorrect altimeter settings doesn't arise.