Re: Do fuel valves ice jam due to water in fuel?

From:         wen@infi.net (W.E. Nichols)
Organization: InfiNet
Date:         17 Sep 96 02:24:40 
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Bob Falkiner <falkiner@interlog.com> wrote:

+it varies by the design.  usually fuel heaters are on the filter (engines
+are certified up to 200 ppm water - a necessity when temperatures drop
+from houston ambient to -56C at altitude as some condensation is
+inevitable)

I forget the exact qualitative analysis for military aircraft fuel, but this
is pretty close.  No free water, intrained water was limited to about what
you state, maybe less.  Particulates were limited to about 5 microns. (?)

+mil fuel has a de-icer glycol type compound added at 0.15 vol%.  some biz
+jets are certified with de-icer which lowers the weight for heating
+equipment.  others use fuel to cool avionics etc and pick up heat.

I don't think the anti-icing fluid is gycol based.  It is nothing more that
a very high priced paint thinner.  Last time I bought a 55 gal drum of it,
the cost was about $500.  Your volume sounds about right.

+but in any case, there is no way to prevent some degree of condensation
+with these kinds of temperature ranges - just different ways of dealing
+with it.

Water in fuel is not a problem if the fuels pukes do the proper QA and the
flight crew does a proper pre flight by checking the low point drains.

Nick
W.E. Nichols    If a frog has wings, it wouldn't bump it's
wen@infi.net    it's ass everytime it jumped.