On Thu, 13 Nov 2008 05:54:34 -0500, "Roger Long"
wrote:

Larry wrote:


It doesn't matter how much....it happens. EVERY airplane at the
airport hangar has tanks filled to the lip because of it. Water in
their fuel spells disaster.

Once again, this simply isn't true and in cases where it is it is because
common knowledge is faulty as Rich says. As a pilot and manager of an
aircraft for a flying club, I checked fuel in an aircraft through the bottom
drain nearly daily year round for a decade and never found a drop except
once after driving rain when the fill cap was not tightened. Like many
aircraft, this one was kept with slack tanks because only two people could
fly it with full tanks and baggage and we didn't want someone to arrive at
the airport and be unable to take off without spending hundreds of dollars
to dispose of drained fuel. This was an aircraft tied down about 200 yards
from the ocean.

There are some "wet wing" aircraft constructions where condensation is more
of a problem but the wings of my plane were similar to a boat in that they
were aluminum inside the wing structure with an air space.

Filling the tanks for the long winter storage, which I have been doing,
helps because it dramatically reduces the surface area of fuel exposed to
air. This works only if you fill up into the vents slightly. I would drain
except I can't get the last inch of fuel out of my tanks. This year, I'm
going to take Rich's suggestion and pipe my sounding tube to a container of
Silica Gel after taping over the vent. In this climate, I haven't had
enough trouble with water problems to make this a permanent installation but
it's a neat idea for southern boats.

For 20 years I was involved in aircraft maintenance, both big and
little airplanes. The common practice was to leave the tanks the way
they were when the plane landed as fuel loads were dependent on cargo
to be carried and length of flight. In fact this was most noticeable
with big aircraft - B-52's for example might take a full fuel load or
if they had an extremely heavy bomb load might take off with minimum
fuel and re-fuel immediately on reaching cruising altitude.

Cheers,

Bruce in Bangkok
(bpaige125atgmaildotcom)