I said earlier that
maybe an airplane capable of descending at an amazing rate would be cleared to a higher level on a single pack.
An old Captain told me a few days ago about the Caravelle:
that outstanding airplane did not have a fixed passengers oxygen system because it was capable of a 12000 ft/min descent (!) thanks to speedbrakes which extended symmetrically above and below the wings (the ones with holes).
So in case of decompression it was capable of reaching safe altitudes in a couple of minutes!
