J

Jake14

Well Known Member
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
 
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Jake14 said:
Are there techniques for shaking the wings before sumping to get all the water down to the sump?
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Quite a few years ago there was an AD against certain Cessna bladder tanks, which required exactly that (rocking the wings). Sometimes called the ‘Rock and Roll’ AD. All internal tank ribs should have drain holes so they cannot dam up water. To check that they’re there, and not clogged up, you probably need to pull the fuel sender to look, although a bright light and a good mirror might work thru the fuel fill opening. Or a long fiber optic device.
 
rain ingress through fuel cap

i had this trouble with my rv-12 which had air vents drilled into the fuel caps. After a night of pouring rain, i sumped the gascolator and tanks and got trace water. Taking off the next fuel atop 100 miles away- i sumped again and got alot of water when i sumped again- meaning i didn’t rock both wings originally and water was trapped behind the baffles at level rest. with my rv-9 yhe fuel caps are not drilled to vent, i presume i can still get water through the fuel caps if my fuel lube/EZ turn and/or gasket adjustment isn’t tight enough. otherwise i guess tank vapor condensation?
Cal
 
Are u sure NO water?

I had a similar occurrence after the heavy rains at OSH 2019. 1/2 hour south of OSH at 5500’. Are u SURE u drained all the water at the sump??? I THOUGHT I had drained all the water. After all, there can’t be more than my drain stick, right. Turned out there was STILL water in the one tank. Another FULL stick+ after refueling at my gas stop. I now verify it’s blue AND I smell it, to make sure.
 
Engine quit after switching tanks.

On pre-flight Check your fuel vents for any obstruction. Mud daubers might have plugged up one vent.
I carry a 3/8” diameter x 20” long clear plastic tubing. Loosen your fuel cap and then hold one end of the tubing firmly against the vent & blow into the other end. You will hear air venting from the fuel filler cap if the vent is not plugged.
 
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Back in 2014 a friend of mine had this same issue with his Cirrus SR-22. After a few days of heavy rain, he took off just fine but when he got to cruise altitude (10,000ft) his engine sputtered and stopped. He declared and emergency and turned back to the airport. When he got to about 2,000ft his engine suddenly roared back to life. He made an uneventful landing.

He sumped the tanks but no water came out. An A&P checked everything but found nothing wrong. They did a test flight and everything worked just fine. He asked me to ferry the plane back for him and I agreed.

A few days later I got there, did an extensive pre-flight and checked the fuel for water. Everything looked fine. But when I checked the fuel caps I found them so loose I could not tell if the "O"-rings were compressing correctly. I tightened the caps until I got the "O"-rings to fully compress, took off and had a completely uneventful flight back.

I summarized that the fuel caps were so loose that one of the "O"-rings was not making a proper seal. With the heavy rain water got into the tank. But in the climb the water went to the rear of the wing tank and everything seemed normal. When he leveled off the water came forward and shut the engine down. Since the propeller kept turning, the fuel pump eventually pumped all the water out. Once the water had been pumped out the engine roared back to life and, except for a huge scare on his part, everything was normal. He never had this problem before because his airplane is always hangered and protected from the rain, except for this one trip where it overnighted on the ramp.

He has not had this problem again.

:cool:
 
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I had a similar issue. engine died 200 ft after take off. Wouldn't restart. Landed successfully on remaining runway.

It turned out to be the tank selector valve. I would be worry that you have the same issue.

It was kind of spooky because after everything else was OK we changed out fuel selector valve and no other issues in a lot of flying in 18 months. But for awhile it wasn't really clear exactly what the problem was.

It also forever cured me of ever, ever, ever not using the full runway available.

We replaced the
Vans with fuel selector valve with an Andair and I would recommend it highly. Kind of pricey but worth it after the engine quit in flight!!!!
 
+1 to ensure the caps are properly adjusted.

However, even if properly adjusted, water will collect in the cap area. If storing outside, tape over the fuel cap area. I use blue painters tape and it works fine to keep water out and is easy to remove.
 
[email protected] said:
I had a similar issue. engine died 200 ft after take off. Wouldn't restart. Landed successfully on remaining runway.

It turned out to be the tank selector valve. I would be worry that you have the same issue.

It was kind of spooky because after everything else was OK we changed out fuel selector valve and no other issues in a lot of flying in 18 months. But for awhile it wasn't really clear exactly what the problem was.

It also forever cured me of ever, ever, ever not using the full runway available.

We replaced the
Vans with fuel selector valve with an Andair and I would recommend it highly. Kind of pricey but worth it after the engine quit in flight!!!!
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Can you explain what was found to be wrong with the Vans fuel valve?
 
BobTurner said:
Quite a few years ago there was an AD against certain Cessna bladder tanks, which required exactly that (rocking the wings). Sometimes called the ‘Rock and Roll’ AD. All internal tank ribs should have drain holes so they cannot dam up water. To check that they’re there, and not clogged up, you probably need to pull the fuel sender to look, although a bright light and a good mirror might work thru the fuel fill opening. Or a long fiber optic device.
Click to expand...

+1

I would be concerned that the builder inadvertently filled some of the drain areas in the ribs with pro seal and you were retaining water next to a rib and after you started flying the water started moving around and made it's way to the pickup area

I would add wing shaking to you routine and would also get that cap adjusted to keep the water out.
 
Thanks for all the helpful comments. The cap seems to be the main culprit, and moving the wing around before sumping makes sense as well..
 
Jake14 said:
Thanks for all the helpful comments. The cap seems to be the main culprit, and moving the wing around before sumping makes sense as well..
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Couple more things...
1. I had a no-transfer light come on over the North Atlantic in December in a BE-350, got back to land ok, hangared the plane overnight, sumped the 8 points (per side) next morning, never found any water. Probable cause was a little bit of water turned to ice and plugged the jet pump orifice (1/8" diameter) in flight at FL270; back on the ground it reverted to liquid state in such a small amount that it was not noticed during sumping. So...you could have experienced a similar issue.
2. After sumping the tank, jiggle the container. If bubbles form and remain, it's all water. If they form and instantly disappear, it's fuel.
 
It has been awhile but essentially by process of elimination everything else was OK and we replaced it and never repeated itself.
Maybe not full proof but was the best idea we had
 
abuura said:
Couple more things...
1. I had a no-transfer light come on over the North Atlantic in December in a BE-350, got back to land ok, hangared the plane overnight, sumped the 8 points (per side) next morning, never found any water. Probable cause was a little bit of water turned to ice and plugged the jet pump orifice (1/8" diameter) in flight at FL270; back on the ground it reverted to liquid state in such a small amount that it was not noticed during sumping. So...you could have experienced a similar issue.
2. After sumping the tank, jiggle the container. If bubbles form and remain, it's all water. If they form and instantly disappear, it's fuel.
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I'm surprised that happened in a turboprop with FSII (aka prist) in Jet A. For gasoline fuel, I suppose that's one benefit of ethanol! Holds some water in solution with the gasoline and it runs right through and out the exhaust.
 
RV6-KPTW said:
If storing outside, tape over the fuel cap area. I use blue painters tape and it works fine to keep water out and is easy to remove.
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FWIW I cut an appropriately sized piece of Silicone Baffle Seal to prevent water from seeping in. I made them just big enough to cover the fuel cap area. They are easy to put on and take off, holds up to quite a strong wind but if you accidentally leave them on they eventually just fly off. I have had these for about 7yrs and have worked great for me. YMMV

:cool:
 
David Z said:
I'm surprised that happened in a turboprop with FSII (aka prist) in Jet A. For gasoline fuel, I suppose that's one benefit of ethanol! Holds some water in solution with the gasoline and it runs right through and out the exhaust.
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The plane had sat for 5 months during a (long) mod, so I assume that gravity worked its insidious little magic and gathered all the junk, water droplets, humidity, etc... into a little ball that settled in the inboard tank's low point and then froze -- either at altitude or during the -25F overnight at Goose Bay.
I don't think it gets that cold in Washington state, but maybe cold enough for a similar thing to happen.
 
mvs163 said:
So maybe a gascolator would have captured the water ?
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A gascolator only captures water if it located at the lowest point in the system, and the water has a path (no up hill legs) and time to gravity flow and settle in the gascolator. The gascolator does not “mechanically” strip water out of the fuel flow. This is why, other than act as a simple fuel filter, they don’t work in low wing airplanes.

Carl
 
Carl Froehlich said:
A gascolator only captures water if it located at the lowest point in the system, and the water has a path (no up hill legs) and time to gravity flow and settle in the gascolator. The gascolator does not “mechanically” strip water out of the fuel flow. This is why, other than act as a simple fuel filter, they don’t work in low wing airplanes.

Carl
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Gascolators do a pretty job of separating out water. Not perfect, but decent. Any water that gets to the gascolator gets the separation treatment. IMHO it does not have to be at the lowest point to work. Most engines have the servo well above the low point and we have seen plenty of examples of water killing the engine; So it must find a way uphill.

Larry
 
lr172 said:
SNIP IMHO it does not have to be at the lowest point to work. Most engines have the servo well above the low point and we have seen plenty of examples of water killing the engine; So it must find a way uphill.

Larry
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Water, just like gas, will go uphill in our fuel pump driven engines. You leave a slug of water in the tank and it will end up in the engine, gascolator or not. The gascolator has just a simple fuel filter, not something like a cyclone water separator.

A gascolator only collects water that gravity flows to it over time. Turn the fuel pump on and you flush it out of the gascolator (thus the reason to drain high wing gascolators as part of the pre-flight). Other than an RV-3 or such with a header tank, there is no gravity flow path for water in our low wing RVs unless of course you somehow mount it in the low point of the tank (or below the tank). For us, stumping the tanks is how we remove water from the fuel.

Carl
 
Tracer 10 said:
On pre-flight Check your fuel vents for any obstruction. Mud daubers might have plugged up one vent.
I carry a 3/8” diameter x 20” long clear plastic tubing. Loosen your fuel cap and then hold one end of the tubing firmly against the vent & blow into the other end. You will hear air venting from the fuel filler cap if the vent is not plugged.
Click to expand...

And if it is below freezing the moisture in your breath might start an ice layer in the vent tube plumbing. I agree with checking the vents. F1 Boss had a great solution with the Rocket wing root vents by taking a piece of large xc safety wire and doubling it over in a hair pin style shape with 1/8" - 3/16" short legs at 90 degree in the bottom end. Then slide that up into the vents. It allows venting and prevents bugs from entering. In several years of summer and winter flights I have not had iced vents nor bugs.
 
abuura said:
The plane had sat for 5 months during a (long) mod, so I assume that gravity worked its insidious little magic and gathered all the junk, water droplets, humidity, etc... into a little ball that settled in the inboard tank's low point and then froze -- either at altitude or during the -25F overnight at Goose Bay.
I don't think it gets that cold in Washington state, but maybe cold enough for a similar thing to happen.
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Any partially filled fuel tank that is vented, but otherwise waterproof can make water by the humidity in the inside air condensing (with temperature cycles) on the inside of the bladder or wing skin as the sun and dark may heat and cool the wing given enough time and the right humidity in the vent air. I have known a few AC owners that will only park their birds with full fuel tanks for this reason.
However this does nothing to prevent water ingress from leaky caps with old, dry o rings.
 
2 things:
1) OP states 2000ft it happened flying over populated area. Experimental aircraft can not fly over congested areas unless taking off and landing. Just FYI food for thought.

2) No gascolator? People "design" their own fuel systems throwing out tried and true well thought out standards. I know fancy in-line car fuel filters, pretty anodized aluminum billet ones. That's fine if you maintain them, but water trap? NO. My diesel car has a fuel filter canister the size of a large Folgers coffee can, but taller.
 
Carl Froehlich said:
Water, just like gas, will go uphill in our fuel pump driven engines. You leave a slug of water in the tank and it will end up in the engine, gascolator or not. The gascolator has just a simple fuel filter, not something like a cyclone water separator.
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Uphill, end up in engine, gascolator or not, cyclone...What? Are you referring to a centrifugal or centrifugal water separators
used on diesels? Gascolator allows fuel/water mix to separate water by gravity. Simple and fairly effective, but the fuel can get to gascolator via a pump not just high wing gravity feed.

Carl Froehlich said:
A gascolator only collects water that gravity flows to it over time. Turn the fuel pump on and you flush it out of the gascolator (thus the reason to drain high wing gascolators as part of the pre-flight). Other than an RV-3 or such with a header tank, there is no gravity flow path for water in our low wing RVs unless of course you somehow mount it in the low point of the tank (or below the tank). For us, stumping the tanks is how we remove water from the fuel. Carl
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Gravity, water is more dense than gas so it sinks. 100% agree sumping tanks is JOB #1. However water can still get pumped gravity or not. I understand what you are saying and don't disagree, but if the debate is gascolator or no gascolator, I say put one in, low wing tail dragger or trike. It's a redundant line of defense.
 
gmcjetpilot said:
2 things:
1) OP states 2000ft it happened flying over populated area. Experimental aircraft can not fly over congested areas unless taking off and landing. Just FYI food for thought.
Click to expand...

That might have been true at some point in the past, I can't say. But it is not true today - my oplims specifically allow it, issued by Mel in 2016.
 
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