Greg Esres wrote in message . ..
I read it to say "cabin pressure altitudes equivalent to
12500-14000MSL

Yes. But this reg has been frequently read to mean 12,500 pressure
altitude. There was a discussion here a while back about why the
"MSL" appeared in the reg; some thought it was a bit of a red herring.

Opinion was divided over whether "pressure altitude" was meant or
"MSL".

For some reason, it now appears quite clear to me the reg means MSL.

I didn't see that thread, the regs have always seemed pretty clear to
be MSL to me. However, your body reacts to pressure altitude (not
density in this case).

-Robert