Shock cooling is probably a myth. I believe both Light Plane
Maintainence and Aviation Consumer have taken that position. It MAY be
true in extreme cases for turbos. According to their research, every
takeoff causes more thermal shock than any descent. As for the
manufacturers, Lycoming recommends running at 50 deg rich of peak,
which G. Braly's research has shown is the absolute worst place to
operate, so they may or may not know what is best about shock cooling.
I certainly wouldn't let a fear of shock cooling my engine cause me to
make an unsafe night(or day) approach, that's for sure. It won't cost
you to use a gentle descent to avoid the possibility of shock cooling,
so that is how I fly, but it probably doesn't matter.

Bud

Timmay wrote:
Dan wrote:


My early years of flying were spent in the Midwest where as long as you
were over 2000 MSL, there were very few obstacles to hit and no
terrain. Now that I have moved out West (Phoenix) I am increasingly
paranoid about hitting terrain at night.

Choosing a cruise altitude is easy (well above anything even close to
your route). However, what I worry about is my letdown to pattern
altitude at the destination airport as well as departure. Short of
filing IFR (which carries with it Oxygen requirements for some local
MEAs) what other strategies do you all use? Any "systems" or
tricks to share, or is it pretty much just look at the sectional and
make a plan?


Descend over lit checkpoints, whether that be an airport or the
neighboring city. It's that simple. I'll never descend over darkness.