Avoiding Shock Cooling in Quick Descent

I read an article that said that if you dont go below 20' MP pressure you
should be ok.
Personally, I reduce power enough where I can do a 500 fpm decent and stay
under the yellow, usually this puts me at about 140 kts IAS, but only if its
smooth air, if I need to stay below Va or if they are trying to slam dunk me
then I drop the landing gear, that and about 25' MP and 2300 rom will give
you around a 800 fpm decent, sometimes faster if you let it. But I try my
best to only do 500 fpm decents.

I was taught to pull power off at about 1' MP per minute.

BTW how is that new T-arrow of yours doing.

"O. Sami Saydjari" wrote:

My engine operating manual (for my Piper Turbo Arrow III) strongly
discourages pulling the power back and doing a quick descent -- it warns
of engine-killing shock cooling. Sounds reasonable to me...but it (and
my airplane manual) does not really seem to say how best to do a fast
descent when you have to.

I inferred that the right thing to do might be to lower the prop speed
to a minimum and ease back power as slowly as you can. Does that sound
about right? How quickly can one expect to pull the throttle back and
not risk shock cooling? If one must get down (say, for air traffic
control reasons, or perhaps because one is trying to take advantage of
favorable winds as long as possible), what is the best procedure. What
about slipping it down? Does that risk the engine or the airframe at
all? I've never done slips at cruise speeds (just on approach), so
please forgive me if this is a naive question.

-Sami
N2057M
Piper Turbo Arrow III