Bucky wrote:
When the engineers
specify a maximum altitude, doesn't it still have to be safe at that
altitude?

Remember, at above 18,000 feet your altimeter is set to 29.92. The
airplane continues to perform and behave based on density altitude. How
much of a difference that is (between PA and DA) up at FL410.. I have no
idea.

In this case, the in the course of trying to obtain max altitude (or
maybe even climb higher) they got too slow. And stalled. Any airplane
will stall given the right circumstances. The autopilot/aircraft systems
tried to correct the situation (by pushing the stick forward, to cause a
descent) and the pilots (incorrectly) chose to override a properly
functioning safety feature.

In this particular stall evolution, the engines both failed because the
smooth airflow going into the engines that were operating at high
power/high flow was disrupted, and for whatever reason they were unable
to restart the engines. There is some specuation about "core lock", in
which sounds like the "shock cooling" equivalent for turbines, going
from high power to no power at high, cold altitudes.

Just what is it about "PILOT ERROR" makes the airframe unsafe? If you
are running with scissors, and your mom says "I wouldnt do that if I
were you".. is it the scissors fault?

Dave