Would you like that fitered or un-filtered?

[Gone Flyin]

The day my Cessna 150 was delivered (ferried) to my airport where I was to take my training, I decided to take fuel samples of the wings, the gascolator and the sump drain port.

This is what came out of the sump drain.

This, after I paid a handsome some for an annual. This caused me to get religion quick and always do a proper fuel inspection before every flight.

In fact, the Cessna POH (and I'm assuming all plane manufacturers) requires the pilot to keep sampling the fuel until there is no presence of water, whatsoever.

My standard technique is to use the Gats Jar and fill it from each of the four ports. That gets me at least 12 ounces each time. I then pour that off into a container through a 200 mesh (74 microns) stainless steel screen. The screen lets the fuel pass but will block the water and any contaminants.

It's the same as the screen used in the Gats Jar.

The screen is held in one of those knitting rings. You can get them at any crafts store for a few dollars. The ring just sits in a funnel inside the container.

I keep sampling this way until I have no water in the jar. Usually, this will take two samples. If its been very humid, I may go into a third, just to be sure.

Then, I set a funnel into one of my tanks and pour the fuel... by now at least a quart or more... back into the tank... again, through the mesh screen.

Works for me.

 

[tawood]

What does this have to do with paying "a handsome some for an annual"?

Glad you caught the water. With that much, there's a chance a person would siphon fuel and only get pure water, thinking its pure fuel.

 

[Jim K]

That first photo is scary. I'm surprised the engine didn't get a slug of water if all that was in the tank.

If you're consistently getting enough water to justify build a bigger sample container, something is badly wrong. I sample my tanks after each fill up, and the only time I've ever found water was when they were filed in the rain, and then only a drop. Water in the fuel should be a freak occurrence, not a regular thing.

If your plane sits outside you need new fuel cap gaskets. If not, you need a new fuel source.

 

[Greg Bockelman]

What year is the 150? Where is the sump? Never saw more than three drains on a 150. 2 wings and 1 firewall.

 

[Salty]

I’ve never been able to figure out how a screen could allow fuel to pass and not water when the water is at the bottom next to the screen. I guess you pour it sideways? Anyway, humidity is never going to produce that much water. Something else is going on.

 

[Cap'n Jack]

I’ve never been able to figure out how a screen could allow fuel to pass and not water when the water is at the bottom next to the screen. I guess you pour it sideways? Anyway, humidity is never going to produce that much water. Something else is going on.

The screen is made of something that the hydrocarbon can "wet", and can pass through. Water can't wet the material, and so can't pass through the holes in the screen. If the holes in the screen are large enough, or there is enough pressure, water will go through the screen too.
Look up "contact angle"- there is a correlation between the angle a drop makes with a surface, and whether the liquid in the drop wets the surface. Mercury is one of the best known non-wetting liquids, and is used to determine pore size.

 

[NoHeat]

The photo in the OP was taken outdoors.

If the plane is normally parked outdoors, that suggests a leaky fuel cap, as was suggested above.

I’m wondering about the ferry pilot. They would be nuts to fly an unknown plane without a full pre-flight inspection. So if they indeed pre-flighted before ferrying, that would suggest water contamination occurred after delivery to the OP.

Edit: the OP mentioned the sample was taken the same day the plane was delivered by the ferry pilot. Was it exposed to rain in between? If not, that’s hard to explain.

 

[Salty]

The screen is made of something that the hydrocarbon can "wet", and can pass through. Water can't wet the material, and so can't pass through the holes in the screen. If the holes in the screen are large enough, or there is enough pressure, water will go through the screen too.
Look up "contact angle"- there is a correlation between the angle a drop makes with a surface, and whether the liquid in the drop wets the surface. Mercury is one of the best known non-wetting liquids, and is used to determine pore size.

I understand that part. My befuddlement is with how the fuel can get past the water to get to the screen when it's floating on top of it, again, I guess if it's not too full and you tilt it sideways, some of the fuel could get to the screen.

 

[Cap'n Jack]

I understand that part. My befuddlement is with how the fuel can get past the water to get to the screen when it's floating on top of it, again, I guess if it's not too full and you tilt it sideways, some of the fuel could get to the screen.

Yes, that's how it works.

 

[Gone Flyin]

So many questions..... so little time.....

The sample in my photo was taken the day of delivery. The ferry pilot was the son of the AI that did the annual.

The plane had sat for some 2 years outside on the ramp prior to my purchase although the fellow who "flipped it" was flying it to some degree.... out of annual... for a few months.

I have never gotten that much water since and I was on the ramp for two years. I now have a hangar but I still do the same ritual.

I want to live a bit longer.

The 75 micro screen is too large for water molecules to pass through but not so for fuel. I use it to to make sure what I put back into my tank is pure 100LL and nothing else.

 

[steingar]

In 20 years I can't recall ever seeing water in the fuel of the three aircraft I've owned. I still check though.

 

[Gone Flyin]

In 20 years I can't recall ever seeing water in the fuel of the three aircraft I've owned. I still check though.

If you keep the tanks relatively full that will help prevent gathering moisture. Luckily, we are not using ethanol blended fuel which will pull moisture in like crazy.

Making sure the rubber cap seals are good, paying through the nose for a hangar, living in a dry climate... all go a long way to reducing.... reducing, but not eliminating the encroachment of moisture into the fuel. There is still the source, which we cannot control.

I draw water every time I check the ports. At least a teaspoon between them, if not more. With a hangar, good cap seals and 10 gallons in each wing tank.

Read too many accident reports of contaminated fuel or not enough fuel from not checking before flight.

Not wanting to make the news, I guess.

 

[luvflyin]

So many questions..... so little time.....

The sample in my photo was taken the day of delivery. The ferry pilot was the son of the AI that did the annual.

The plane had sat for some 2 years outside on the ramp prior to my purchase although the fellow who "flipped it" was flying it to some degree.... out of annual... for a few months.

I have never gotten that much water since and I was on the ramp for two years. I now have a hangar but I still do the same ritual.

I want to live a bit longer.

The 75 micro screen is too large for water molecules to pass through but not so for fuel. I use it to to make sure what I put back into my tank is pure 100LL and nothing else.

So it sounds like you are still getting some water regularly. Is that so?

 

[Dana]

I used to get water in the fuel when I had a T-Craft tied down outdoors back in the 1980s, never since. Rainwater... though there was one time I found myself down on a farm field with a gascolator full of water and sludge... the first time I filled up from the FBO's new fuel truck. You can imagine that he and I had words...

 

[Gone Flyin]

... I found myself down on a farm field with a gascolator full of water and sludge... the first time I filled up from the FBO's new fuel truck. You can imagine that he and I had words...

And that's what I mean about not having control over the source.

There can be water in that truck, in the stationary tank, in the underground piping to the fuel pump, in the rubber hose that you run to your plane.

If water in the fuel was not an issue why would we need to be using Gats Jars all the time.

The one time you do not sump fuel may be the time you had water.

Just do it every flight.

 

[Daleandee]

The 75 micro screen is too large for water molecules to pass through but not so for fuel. I use it to to make sure what I put back into my tank is pure 100LL and nothing else.

I wouldn't do that ... but that's just me.

 

[Salty]

I wouldn't do that ... but that's just me.

Not just you.

 

[455 Bravo Uniform]

That cloudy mess tells me it’s not just water. Do you use mogas? I’ve seen that when I’m trying to determine the alcohol-gasoline ratio of ethanol fuels by mixing with water.

Find your root-cause.

 

[tawood]

That cloudy mess tells me it’s not just water. Do you use mogas? I’ve seen that when I’m trying to determine the alcohol-gasoline ratio of ethanol fuels by mixing with water.

Find your root-cause.

That's the first thing I thought of when I saw it too. I used to test my mogas for ethanol. Every now and then, I'd intentionally test some gas that knowingly has ethanol in it as a "control", and it looked just like the OPs photo when I did.

 

[NoHeat]

I draw water every time I check the ports. At least a teaspoon between them, if not more. With a hangar, good cap seals and 10 gallons in each wing tank.

If it’s hangared, I can’t imagine where new water is coming from, unless you re-fuel and the fuel source is contaminated.

Otherwise, it’s not new water - maybe it was water in the tank to start with and taking time to settle, or it’s something other than water.

 

[Dan Thomas]

The 75 micro screen is too large for water molecules to pass through but not so for fuel.

Haha. Good one. Such big molecules you have.

Water has surface tension. Gasoline does not. That's why the water won't flow through a fine screen that's already wet with fuel.

 

[Doc Holliday]

If you keep the tanks relatively full that will help prevent gathering moisture. Luckily, we are not using ethanol blended fuel which will pull moisture in like crazy.

Making sure the rubber cap seals are good, paying through the nose for a hangar, living in a dry climate... all go a long way to reducing.... reducing, but not eliminating the encroachment of moisture into the fuel. There is still the source, which we cannot control.

I draw water every time I check the ports. At least a teaspoon between them, if not more. With a hangar, good cap seals and 10 gallons in each wing tank.

Read too many accident reports of contaminated fuel or not enough fuel from not checking before flight.

Not wanting to make the news, I guess.

I've owned several aircraft over 40+ years, and yet it was an extremely rare occasion I found water in my fuel tanks or fuel strainers.

 

[Kenny Phillips]

The day my Cessna 150 was delivered (ferried) to my airport where I was to take my training, I decided to take fuel samples of the wings, the gascolator and the sump drain port.

This is what came out of the sump drain.

This, after I paid a handsome some for an annual. This caused me to get religion quick and always do a proper fuel inspection before every flight.

In fact, the Cessna POH (and I'm assuming all plane manufacturers) requires the pilot to keep sampling the fuel until there is no presence of water, whatsoever.

My standard technique is to use the Gats Jar and fill it from each of the four ports. That gets me at least 12 ounces each time. I then pour that off into a container through a 200 mesh (74 microns) stainless steel screen. The screen lets the fuel pass but will block the water and any contaminants.

It's the same as the screen used in the Gats Jar.

The screen is held in one of those knitting rings. You can get them at any crafts store for a few dollars. The ring just sits in a funnel inside the container.

I keep sampling this way until I have no water in the jar. Usually, this will take two samples. If its been very humid, I may go into a third, just to be sure.

Then, I set a funnel into one of my tanks and pour the fuel... by now at least a quart or more... back into the tank... again, through the mesh screen.

Works for me.

From personal experience in a 150, you may get nothing sumping on the ramp, and have a big glob knock out the engine 50 feet in the air. Luckily on a 6K strip.

 

[Cap'n Jack]

Haha. Good one. Such big molecules you have.

Water has surface tension. Gasoline does not. That's why the water won't flow through a fine screen that's already wet with fuel.

See post #6. Water is unable to wet the mesh, and so is unable to get through a mesh of that size without additional pressure. If the mesh were made from another material, such as metal without a coating, water would be able to get through, although its surface tension is unchanged. Gasoline does have a surface tension, less than water- see: https://pubs.acs.org/doi/pdf/10.1021/ef060231c.

 

[wanttaja]

Back in the '80s, I tanked up at a local airport, putting about ten gallons in my 150's tanks. Checking the fuel afterwards, it was a nice red color (back in the 80 octane days) but had some bubbles in it. The bubbles neither rose nor fell.

I talked to several people in the office (including my instructor) and they all just shrugged it off. I took off...and about five minutes later, the engine started running rough. Firewalled the throttle to get the most altitude I could, and headed to the nearest airport (which happened to be my home base). Engine died on final, landed safely with the prop stopped.

Fuel sample taken after landing was identical to the OP's sample. In fact, sample after SAMPLE looked like that. I eventually started using an empty oil container to drain the sumps into. Had to take ~2 gallons out of each tank before it ran pure.

Turns out the FBO's fill ports for its fuel tanks were below ground level, and, in fact, at a low point on the ramp. It had rained, and the seal on their gas cap had leaked and let water into the tank. The tank had a water sensor that was supposed to shut off flow...it hadn't worked. The pump action had apparently mixed the water with the fuel, and a few minutes of vibration from my engine caused it to separate again.

Fortunately, I was only the third person to tank up that day. They found just a cup or so in the tanks of the first airplane, but the second plane (which was based there, and had parked after filling) had more than five gallons of water.....

Lemons/lemonade situation: I posted about my adventure to the aviation group on USENET, then polished it up and sent it to FLYING magazine. They published as a "I Learned About Flying From That" in 1987. It was my first article sale.

Ron Wanttaja

 

[mondtster]

Turns out the FBO's fill ports for its fuel tanks were below ground level, and, in fact, at a low point on the ramp. It had rained, and the seal on their gas cap had leaked and let water into the tank. The tank had a water sensor that was supposed to shut off flow...it hadn't worked. The pump action had apparently mixed the water with the fuel, and a few minutes of vibration from my engine caused it to separate again.

One of the airports I work at has fill ports like that. The (former) airport manager would reach in and remove the tank caps to drain the cavity. It drained it...right into the fuel tank. I never found any water in the fuel there and never heard of anybody else having trouble so apparently the water separator system worked. I'd say the lesson out of this discovery was to not assume there is no water in the fuel, check it to make absolutely sure.

 

[JAWS]

There is a good STC to install a quick drain in the fuel shutoff sump line that usually has a lockwired plug or cap in it. Located on the belly. Allows you to drain the line at each pre-flight versus only at annual. Un-modded ones always get looked at during annual, right? This should be a must have.

Still not sure how this relates to a handsome annual.

And I wouldn't use that mixture in a lawnmower, let alone an airplane.

 

[JAWS]

Just remembered this site, in case you'd like to see what happens to water in a 150 fuel tank.

http://www.sumpthis.com/cessna150andcessna152tanktest/cessna150tanktestimages1024x768.htm

 

[wanttaja]

One of the airports I work at has fill ports like that. The (former) airport manager would reach in and remove the tank caps to drain the cavity. It drained it...right into the fuel tank. I never found any water in the fuel there and never heard of anybody else having trouble so apparently the water separator system worked. I'd say the lesson out of this discovery was to not assume there is no water in the fuel, check it to make absolutely sure.

I mentioned in my post that no one at the FBO could explain where the bubbles came from. What I didn't mention is that they were emphatic that it *couldn't* be water... because of the water detection/separator system.

Yet, of course, it was. Turns out that the detector system had half-way worked...it was supposed to shut down the fuel flow, but it only reduced the rate. I remember when I was filling the 150's tanks I was saying, "Jeeze, this is slow...."

Ron Wanttaja

 

[Dan Thomas]

Just remembered this site, in case you'd like to see what happens to water in a 150 fuel tank.

http://www.sumpthis.com/cessna150andcessna152tanktest/cessna150tanktestimages1024x768.htm

Yup. But the 150 isn't the only one. The Cessna singles with bladder tanks have had problems retaining water due to wrinkles in the bottom of the bladder. The water was getting in via the infamous flush fuel caps, mostly. Owners/mechanics let the O-rings in them deteriorate, and if they replaced anything it was the outer O-ring that sealed the cap in its filler neck. They'd overlook the O-ring on the locking shaft. Water would pool in the lock lever cavity and run into the tank. Lots of it. Cessna sold a kit to convert to the same raised caps you find on the 172 to get away from that. Until the new caps were installed, the AD required to you perform a truly onerous (and violent) procedure to work the water to the quick-drain:

(A) Fabricate using letters at least .10 inches in height, and install a placard in full view of the pilot which states as follows:

"Prior to flight following exposure to rain, sleet, snow, or after fueling from an unfiltered fuel source:

1. Drain and catch the contents of the fuel gascolator, wing, and (if equipped) reservoir tank sumps and check for water contamination.

2. Place the airplane on a level surface and lower the tail to within 5 inches of the ground (on nose gear airplanes).

3. Rock the wings 10 inches up and 10 inches down at least 12 times.

4. Drain and catch the contents of the fuel gascolator, wing, and (if equipped) reservoir tank sumps and check for water contamination.

5. If water is found in step 4 above, repeat steps 3 and 4 until no additional water is detected, or drain the entire airplane fuel system.

Now, that procedure should have been applied to the 150 as well.

Cessna also sold a kit to move the quick-drains inboard and aft about 3/8" inch to pull the diagonal wrinkles out of the bladder.

https://rgl.faa.gov/Regulatory_and_...7CA32CBFD7107A87862569B9004D1566?OpenDocument

 

[Bathman]

If your plane sits outside you need new fuel cap gaskets. If not, you need a new fuel source.

Coudn't agree more. And remember when you take a fuel sample that's all it is.

I've seen fuel caps left off followed by heavy rain. You take samples until the fuel runs clean then go and fly. Yet 10 hours later you are still finding water in the fuel you can try lifiting a wing to shake it to the low point but you won't get it all.

 

[Gary Ward]

The day my Cessna 150 was delivered (ferried) to my airport where I was to take my training, I decided to take fuel samples of the wings, the gascolator and the sump drain port.

This is what came out of the sump drain.

This, after I paid a handsome some for an annual. This caused me to get religion quick and always do a proper fuel inspection before every flight.

In fact, the Cessna POH (and I'm assuming all plane manufacturers) requires the pilot to keep sampling the fuel until there is no presence of water, whatsoever.

My standard technique is to use the Gats Jar and fill it from each of the four ports. That gets me at least 12 ounces each time. I then pour that off into a container through a 200 mesh (74 microns) stainless steel screen. The screen lets the fuel pass but will block the water and any contaminants.

It's the same as the screen used in the Gats Jar.

The screen is held in one of those knitting rings. You can get them at any crafts store for a few dollars. The ring just sits in a funnel inside the container.

I keep sampling this way until I have no water in the jar. Usually, this will take two samples. If its been very humid, I may go into a third, just to be sure.

Then, I set a funnel into one of my tanks and pour the fuel... by now at least a quart or more... back into the tank... again, through the mesh screen.

Works for me.

I can't believe someone flew the plane with that much water in the fuel tanks?

I recommend that you coat your fill cap gaskets/o rings with fuel lube. I think helps keeps water from getting by your fill caps during rain and plane washes.

 

[Domenick]

...The 75 micro screen is too large for water molecules to pass through but not so for fuel. ...

Water molecules are considerably smaller than the hydrocarbons making up aviation fuel.

 

[Dan Thomas]

I recommend that you coat your fill cap gaskets/o rings with fuel lube. I think helps keeps water from getting by your fill caps during rain and plane washes.

Fuel Lube will attract dust and grit. The only fuel-filler place I had any success with it was in between the cap and gasket, where it reduces the amount of friction and effort require to open or close the cap. If the gasket isn't sealing, a new cap or gasket is necessary. Sometimes the steel filler neck is rust-pitted.

I have often found the cap's little red silicone rubber vent check valve aged and drooping and not sealing properly. That lets in rain and melting snow. Rain splashes as it hits the wing, throwing droplets into the cap's vent holes, and it runs down against that valve. If the valve is shot it gets into the tank. If the valve is good, the water will stop inside the cap and eventually evaporate. Snow on the wing forms a dam around the cap and holds water against that cap, and lots can flow in if the valve is pooched.

 

[bluerooster]

It takes quite a bit of water to show up in a fuel sample from a C150 sump drain.

http://www.sumpthis.com/cessna150andcessna152tanktest/cessna150tanktestimages1024x768.htm

 

[Matthew Rogers]

It takes quite a bit of water to show up in a fuel sample from a C150 sump drain.

http://www.sumpthis.com/cessna150andcessna152tanktest/cessna150tanktestimages1024x768.htm

I have a C150. That test does not capture real world conditions in any way. My airplane is parked outside in the Northeast, so plenty of rain, snow, and ice. We do occasionally get a drop or two of water in the tank, probably from condensation or fuel contamination (Mogas). But only a drop or two every few weeks at most. Based on this test, I would only be seeing that drop of water after the tank had more than a half gallon of water already inside it.

I have used a boroscope inside the tank to check out the fuel vent line valve and saw not a single drop of water in the tank. So where is the 80oz of water that supposedly gets trapped and can’t ever drain out? It is well meaning, but sensationalism nonetheless. If not, how can you explain getting a single drop or two out and having a completely “dry” tank otherwise?

 

[Lachlan]

Mr. Rogers has a point. I don't find any water in my 150 tanks, and I'm parked outside from May through the end of flyable weather, usually in November. (We don't plow the grass runway in the winter. It's for ski flying. ) I keep a cover on my airplane, though, and it covers the fuel caps, but I've still never seen water or collected any from the 4 sumps on my 150M. There's something VERY wrong with the OP's pics, situation, or other. Very, very wrong.

 

[asicer]

It takes quite a bit of water to show up in a fuel sample from a C150 sump drain.

http://www.sumpthis.com/cessna150andcessna152tanktest/cessna150tanktestimages1024x768.htm

I'd love to see the same test on a C172SP with its 5 drains on each tank.

 

[Dan Thomas]

I have a C150. That test does not capture real world conditions in any way. My airplane is parked outside in the Northeast, so plenty of rain, snow, and ice. We do occasionally get a drop or two of water in the tank, probably from condensation or fuel contamination (Mogas). But only a drop or two every few weeks at most. Based on this test, I would only be seeing that drop of water after the tank had more than a half gallon of water already inside it.

I have used a boroscope inside the tank to check out the fuel vent line valve and saw not a single drop of water in the tank. So where is the 80oz of water that supposedly gets trapped and can’t ever drain out? It is well meaning, but sensationalism nonetheless. If not, how can you explain getting a single drop or two out and having a completely “dry” tank otherwise?

That article claims that the airplane was in normal ground attitude. Yeah, if the nosewheel strut was completely collapsed, maybe. Still, that depression in the tank right at the outlet is dangerous, and the 150 is the only place I've seen that. Most wing tanks are flat-bottomed and the outlet is a little above the bottom so that water doesn't run into it.

I'd keep the nose strut inflated to spec, make sure the airplane is on level ground during preflight, and maybe raise the nose for a few seconds before sumping the tanks. DON'T push down on the stab; that cracks the flimsy forward spar, which is just a fold in the skins. Push down on the fuselage right over a bulkhead, identified by the rivet line. And do that carefully or you could deform the bulkhead and skin. With a 150, and with its prop horizontal, you could lift the nose by grabbing both prop blades right close to the spinner. Doesn't take much force.

 

[Dan Thomas]

I'd love to see the same test on a C172SP with its 5 drains on each tank.

Those tanks would perform properly. They're integral tanks, just the wing structure sealed up, and the drains are positioned in the low spots at ribs and stiffeners. Cessna was tired of being sued for accidents caused by owners claiming that their tanks trapped water. Owners that often ignored all the SBs, sometimes the ADs.