wrote in message
ups.com...
Mike,

I'm not referring to water in the fuel as we deal with in piston
pounders (and where it would be expected to affect a number of
airplanes), but rather the normal moisture entrained in fuel and that
processes through the system without any effect except at high altitude
where it's so terribly cold and the entrained moisture freezes and can
clog filters with the very small ice particles unless something like
PRIST is used. (Although one poster was correct, it usually takes more
than a few minutes to cool the fuel to the point where the entrained
water freezes. It's more of a concern after about an hour at cruise.)

May not be a good theory as it appears the crew let the speed
deteriorate badly in the final climb to 410 and it continued to bleed
off once there.

All the best,
Rick


I would still expect that a lot of Jet A buyers are going to FL410 (or
higher) and that if there was enough water in the fuel to crystalize and
block the fuel system to the extent that the engines failed that it would
have affected other planes too. Also, at least in my airplane, you have
some time between when the filter bypass light comes on and when the engines
flame out since the fuel lines are a lot bigger that the filter pores and it
takes more ice to clog them. I always look for what is unique to the
situation and what is common. So, I think that the problem was, most
likely, not the fuel because many others probably bought the fuel and flew
at least as high for at least as long.

I would guess that the pilots had never been anywhere close to FL410 since
it appears unlikely that the plane could reach that altitude with passengers
aboard if it can barely get there empty. They probably didn't remember the
cautions about high altitude flight in the manual. Why they chose to
override the shaker or not set up their glide towards an airport is
baffling.

Mike
MU-2