After filling up the tanks, flew home (30nm) and the aircraft was tied down outside for 4 rainy days. Next flight, pulled it out onto the ramp and sumped the tanks with no trace of water in either one. I've almost stopped sumping since there's been no problem in 5 years. Took off and after about 10 min, switched tanks. About 5-8 seconds later, the engine started sputtering and seemed about to stop. pushed all the knobs forward and turned on the boost pump but no change. Switched back to the other tank and after about 8 sec the rpm came back and all was normal. A very exciting 20 sec since I was only 2000 AGL over a populated area.
Landed at the nearest airport and sumped the tanks several times and all looked the same as the pre-flight sumps: no traces of water. Back to altitude, switched tanks again and all was ok.
Is it possible for Van's fuel tanks to collect significant amounts of water away from the sump so that it could drain down to the pickup after takeoff?
The fuel cap on the problem tank is new (SPRL) so that's what I suspected, but I've examined it and tested the seal while installing it and it seems fine.
I'm just puzzled as to why I didn't see any water during all the sumps, not even a little. Are there techniques for shaking the wings before sumping to get all the water down to the sump?
One other possibility: the airplane was outside during freezing rain and was coated with a sheet of ice. Two days later, the ice was melted and I went to fill the tanks, The first time I used the problem tank since the ice melted was when the problem occurred so maybe there was some fuel line blockage..
Any insights would be appreciated
Landed at the nearest airport and sumped the tanks several times and all looked the same as the pre-flight sumps: no traces of water. Back to altitude, switched tanks again and all was ok.
Is it possible for Van's fuel tanks to collect significant amounts of water away from the sump so that it could drain down to the pickup after takeoff?
The fuel cap on the problem tank is new (SPRL) so that's what I suspected, but I've examined it and tested the seal while installing it and it seems fine.
I'm just puzzled as to why I didn't see any water during all the sumps, not even a little. Are there techniques for shaking the wings before sumping to get all the water down to the sump?
One other possibility: the airplane was outside during freezing rain and was coated with a sheet of ice. Two days later, the ice was melted and I went to fill the tanks, The first time I used the problem tank since the ice melted was when the problem occurred so maybe there was some fuel line blockage..
Any insights would be appreciated
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