Roy Smith writes:

The MSA altitudes are for situational awareness and emergency use only.
When you're cleared for the approach, you can descend to the minimum
altitude specified for the route segment that you're established on,
which has nothing to do with the MSA.

Those are the U.S. rules. In Canada, the MSA is operational -- a
clearance to the approach automatically includes a clearance to MSA
unless stated otherwise, and the controllers expect you to know that
(just as a VFR clearance to any leg of the circuit clears you to
descend to circuit altitude).

Of course, if you're under radar coverage and being vectored, you
won't be cleared for the approach until you're about to intercept it
anyway.


All the best,


David