James Thursby wrote:
> I thought you might like to be aware of the fact that the fuel tanks in our
> airplanes while extremely safe and crashworthy, also have a small quirk
> present. Even if the tank is drained and flushed with water repeatedly, the
> plastic seems to permeate vapors afterwards. How do I know this you ask?
> Last Wednesday I was installing a capacitance fuel gauge in a previously
> flying Europa, that we had flushed with water and drained, and in the
> process of cutting the 2 inch hole with a heated drill bit and pliers, set
> off fumes in the tank when a little piece of the plastic caught fire. (if
> you have ever seen a empty alcohol bottle lit with a match, you get the
> idea) The tank had been flushed and then had sat overnight. Both of us had
> smelled the filler and could not detect any fumes. We where cutting it with
> a heated wire, so there wasn't any flame or sparking from an electric tool
> present. I only waited a week to tell because it was difficult to type
> earlier. The plane is fine and will be ready for it's third lease on life
> shortly, and my left hand should be fine in a few weeks. (yes I am a lefty)
> It just goes to show you that even when you take what you think are all the
> necessary precautions, Murphy is still about.
This might not necessarily be the case.
With a background in motor racing I know of more than one case where
people have set up fuel tanks with a hose water flush for several hours,
only to have the thing explode as soon as they start welding. Petrol is
a devil of a substance to purge when you are going to have sparks or
flames around.
Having said that, who knows what is happening in these plastic tanks??
Dave Watts, G-BXDY
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