Bert,
Do you have the black rubber gasket in place which is supposed to go
around the header tank fuel filler and the top cowling? This gasket
is meant to seal the opening so spilled fuel will not enter the cockpit.
Have you checked your fuel return line to see if it is plugged? It
should be able to return fuel to your wing tanks faster than your fuel
pump can bring it into the header tank.
Have you checked to see if the restrictor is in place in the fuel pump
elbow fitting? The restrictor is meant to keep the fuel flow from the
pump from overflowing the header tank.
My opinion is that you have one or more of the above problems.
Syd
On Jan 5, 2009, at 9:58 PM, Bert wrote:
While on a leasurely sight seeing trip along the Mississippi, fuel
began pouring into the cockpit. It was not a drip. It was a flow.
It hit my feet, soaking my Hush Puppies. The A&P at the our emergency
landing field could find no leak. He suggested we try flying with
the electric fuel pump off. Turning it on only to return the header
to 80-90% full each time it registered 1/2 empty. The trick worked
and we flew home. The first time the indicator said full (just about
the same time we trimed out after the climb out) the leak started.
Turning the pump off yielded an almost instantaeous halt to the leak.
My home field A&P can find NO leak. No bad fittings, no cracked
lines, no split seams, holes, corrosion, nothing. A presuure test
with a full tank was negative. We spent the morning today running
high speed taxi tests up to take off speeds with the electric pump on
and the header tank full. After twenty minutes we got nothing.
I've had a fuel smell in the cockpit off and on for the past three
years that no one could pin down. Flying home with the electric pump
off, there was no fuel smell. During the high speed tests today there
was a slight fuel smell.
The problem flight was the first long flight I had made after
installing a new header tank gas cap and gasket, the type with the
glass covered fuel level indicator.
The FBO owner and one of the most respected aviation old timers in
the area, suspects the fuel pump is building up a pressure so that
fuel is being forced out the vent hole in the front of the cap. In a
hundred mile per hour wind stream, it is almost instantly forced down
and under the cowling where it makes its way over and around the
tank, eventually pouring over my feet. There is no doubt the flow
stops immediately after the fuel pump is turned off.
Does anyone have any ideas on how to proceed? Had a similar
experience? The negative results from the pressure test have me
stumped.
Bert Hampton
N99618 at 3K6
