On Monday I received an email and invoice that my plane's annual was

completed and I planned to pick it up next week.  On Tuesday morning I

received a call from the shop telling me that there was 2" of jet a in

my

cockpit! Never happened before!  Upon further investigation, they

found

that the aluminum belly tank vent line had been zip tied to the

braided

stainless hydraulic lines. running through the floor of my cabin.  My

builder said that he would have never zip tied these 2 metals

together.

Since receiving the airworthiness certificate in 2006, my plane has

been

inspected by several different excellent lancair knowledgable

mechanics

including Lancair and noone has ever said anything about the aluminum

and

stainless lines being so close in proximity.  As to who zip tied them

together and when-I don't know.



As evidenced by the attached photo electrolysis had occurred causing a

hole

in the aluminum vent tubing.  The fuel from the wing tanks flowed into

the

belly tank then through the cracked aluminum vent tubing into my

cabin.

Fortunately this did not occur in flight as the pressurization would

have

probably pushed air into the belly tank and subsequently overboard

through

the wing vents!  I would have had plenty of fuel but none in the belly

tank

feeding the engine thus unporting the engine.



I wonder if I would have recognized that in flight.  Glad I didn't

find

out!  But after thinking about it I have committed to my mind that if

the

belly tank seems to be emptying inexplicably, descend, turn off

pressurization and land!



The point of my post is just to make everyone aware of the obvious.

Avoid

putting different metals in close proximity or directly in contact

with

carbon fiber which can also cause electrolysis.  We have changed most

of

our tubing to stainless but obviously not the belly tank vent-until

now!



As a neurosurgeon, we are always cognizant of making sure to avoid

using 2

different metal implants in proximity ie stainless steel and titanium(2

common metals

used in the spine) but this event really drove the point home!



Fly safely!  %#*$ happens out there!



David Weinsweig

N750DW Propjet

weinsweigd [at] gmail.com

304-633-5221

 

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