Hi fellows,

I just discovered the following problem with my header tank.

In my – not flying yet – LNC 360 I have since 1 – 2 years about 3-4 gallons of mogas for run-up testing etc.. The headertank is sealed with the standard fuel tank sealer Jeffco 9700.

Yesterday evening I wanted to change something on the fuel level sensor and discovered that the backplane with the screws holding the sensor in place is loose. Closer evaluation showed that the sealer was on large portions in the tank released from the lower tank basin. The upper cover is OK. Also the glue holding the backplate in place was complete released.

The Jeffco felt hard and sticked  to other surfaces OK. I do not believe that it is a mixing or surface preparation problem – even it could. But the header tank is made from two different materials – the lower basin (or the “basin” itself) is made of pure glass – and probably different from the other glass in the plane. The upper cover is the honeycomb material on which the Jeffco glues just fine.

Now your opinions / experience is asked:

1.       As it is European mogas with ethanol – could that be the reason ?

2.       If it is a preparation problem – why does it stick to other surfaces – and the Jeffco should be sealing and the adhesive should not be influenced by the gas... ?

3.       Is the Jeffco a bad batch ?

4.       Does one need a fuel tank sealer anyhow in the header tank due to the other material (except the upper surface) ?

5.       Any experience with mogas “contaminating” the glass with respect to further proceedings like re-covering again with sealer ?

Any ideas are welcome – I have some problems in getting in touch with Jeffco and could not reach yet Lancair.

Thanks in advance

Peter

LNC 360 MKII, D-EPSO, 95% (?)