And that why we preflight, folks

This is how we lost our dear friend, Walt Meziere. Miss him every day.

Sump those tanks - and do it right!
 
Was there any portion of the previous flight in freezing temperatures that might have trapped some ice from the previous fueling?
 
IK04 said:
Was there any portion of the previous flight in freezing temperatures that might have trapped some ice from the previous fueling?
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May have been, don't know the temps.
 
For those who have read this far, our club had a specific tie down procedure for our Cessna's.

Pull the tail down until the nose gear is mostly extended and secure it, then tie the wings snug.

Two purposes, first, reduce the internal pressure on the seals of the strut.

Second, the water runs to the sump, at the back of the tank,, and accumulates for sumping at the next flight.

Our tanks were different from the ones in the test, with both the fuel line and the sump at inboard corners of the tank, the sump fitting was, and on our present model is, next to the fuselage, where it should be.

I don't understand a sump at an outboard corner, as that is higher than the inboard corner.

After refueling en route, I customarily depress the tail, and then rock the plane with the wing struts, to settle water into the sump, before checking for water. Refueling is done first, then weather briefing and flight plan for the next leg. Walk around preflight and sumping is last step before climbing in and starting the engine.

Our birds were all kept outdoors, and we kept track of the cap seals, so water wa minimal, but condensation is an unavoidable condition, and small amounts of water were common. Water in the gascolator, on the other hand was rare, due to careful and regular sumping. Our present, M model Cessna 172, has a sump under the belly, and sumps the fuel delivered from the fuel line outlet of the tanks, and very likely due to our tail low tie down practice, water from the belly sump is rare.
 
smv said:
...and to think there are CFIs out there that advocate (and teach) not sumping "during the winter". Their reasoning? Any water in the tank will be frozen anyway. By sumping when there is ice in the tank you can cause the sump to be blocked open or damage the O-ring. o_O
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Okay I’ll bite. Have been living where we have freezing temps every year of my life abs I’ve never met or even heard of a CFI pushing something this stupid.

I’ve seen a FEW things similar for people flying in -10F or lower to places where there is ZERO maintenance or parts coming for days to be VERY careful messing with mechanical things I’m weather THAT cold because if you break something you’re spending a very long cold night in the airplane. But that’s extreme stuff.

So where are these doofuses and what’s the climate like where they live? LOL.
 
smv said:
A flight school in North Dakota. All the fuel cups were pulled from the rental/instruction aircraft a month ago. Had to carry my own if I wanted my students to sump.

o_O
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Ugh. Not THE um... flight school in North Dakota, right?
 
I made the mistake of sumping a tank on a 207 in 15 degree temps when I first went to Alaska. I won't do that again.

The sump stuck open and a constant stream of gas was pouring out. A mechanic came out and used his cigarette lighter to thaw it enough to close it. Ok, not really. He just removed the frozen sump and replaced it with a warm one.

Isopropyl is your friend when the temperature never rises above freezing for several months.
 
smv said:
A flight school in North Dakota. All the fuel cups were pulled from the rental/instruction aircraft a month ago. Had to carry my own if I wanted my students to sump.

o_O
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So how much water have you found in the fuel tanks during any season in North Dakota?

My observation has been that in environments that actually get cold enough to freeze water in the fuel tank generally are dry enough that there is little water that ends up in the fuel tank. I have NEVER seen anywhere near the amount of water in the fuel that I have seen every time I’ve been in the humid southeast.

Im not saying that a person shouldn’t check the fuel but I can see how lots of experience in that climate would develop a callous attitude toward water contamination.
 
smv said:
A flight school in North Dakota. All the fuel cups were pulled from the rental/instruction aircraft a month ago. Had to carry my own if I wanted my students to sump.

o_O
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That sounds like a lawsuit in the making.
 
smv said:
I would rather be standing on the ground watching the fuel drain from a sump than to be in the air when whatever it was that caused the sump to stick open finds its way further down the fuel system and possible clogs something else...

:nonod:
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It was ice that caused it to stick open. If I had not fooled with it, there would have been no problem.

Again, Isopropyl is your friend in cold weather flying.
 
If using mogas, can you put isopropyl in the fuel for the winter? What ratio? Any one that has actually used it, please provide more specifics for temperature range, ratio, anywhere to look for technical advise.
 
In Alaska we would use 1 ounce Isopropyl for every 10 gallons at all temperatures.

It is added while fueling to catch any possible ice crystals or water droplets in the gas. The theory is that the Isopropyl catches the ice crystals or water droplets that are suspended in the fuel then mixes in with the fuel and is burned through the engine.

Isopropyl also will not separate the tetraethyl out of leaded fuel.

I have added Isopropyl with mogas in carbureted trucks and tractors with success when I suspected a small amount water in the fuel tank. Not much luck though, when there is more water than fuel in the tank...
 
Zeldman said:
In Alaska we would use 1 ounce Isopropyl for every 10 gallons at all temperatures.

It is added while fueling to catch any possible ice crystals or water droplets in the gas. The theory is that the Isopropyl catches the ice crystals or water droplets that are suspended in the fuel then mixes in with the fuel and is burned through the engine.

Isopropyl also will not separate the tetraethyl out of leaded fuel.

I have added Isopropyl with mogas in carbureted trucks and tractors with success when I suspected a small amount water in the fuel tank. Not much luck though, when there is more water than fuel in the tank...
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Once upon a time.... it was routine in some areas to add Drygas to auto fuel tanks in the winter. Drygas is (or was) alcohol. If I remember correctly, the dosage was a can for a full gas tank, or about an ounce per 3 gallons. As filling stations got better, and cars got better, and vapor recovery came in the need for Drygas evaporated. I suppose it's still sold, but it's not commonplace.
 
Drugstore isopropyl is only 70% isopropyl. The rest is water and a bit of glycerin. If you dump it in your tanks, you're adding water.

Mogas STCs forbid the use of any mogas containing alcohols, specifically ethanol, IIRC. It damages fuel system components, which in airplanes are made of different stuff than in cars. But here in the frozen north, all winter mogas has a little alcohol in it to help prevent fuel system freeze-up, usually less than one percent.

One of our clients had a sump drain stick open due to ice. If the tanks were sumped more frequently this would not happen. Sump it before flight, after refuelling, after the flight, and every time you go check on the airplane in its tiedown spot. Make sure the fuel caps are sealing properly; that's where most water gets in. If the fuel truck or pumps have the proper water-stop filters you won't get water from them.
 
smv said:
I would rather be standing on the ground watching the fuel drain from a sump than to be in the air when whatever it was that caused the sump to stick open finds its way further down the fuel system and possible clogs something else...

:nonod:
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Sump drains will leak due to ice or particles that get stuck in them. The fuel outlet from the tank has a coarse screen "finger" on it that keeps anything large enough to block the system from entering the outlet line. Smaller stuff that gets out gets caught by the fuel strainer, and anything tiny enough to get past the strainer is stopped by the really fine screen in the carb inlet or fuel injection servo.

In most airplanes there's a low spot somewhere along the fuel line that water could settle in and freeze and stop the flow. Not sumping in the winter can lead to that when the water in the tank thaws out and gets into the outlet and down into that low spot. The FARs require a drain at that point, but they don't require a quick-drain valve and so most have a plug like we see on the bellies of the Cessna singles. It's in the fuel selector, which is the low spot, and one of the posters here has a sump drain there like it should have. I've found those valves with a lot of crud in them because the plug was never removed in 40 years even though Cessna stipulates removing and draining it a bit every 100 hours.
 
Lots of "I drained it into a bucket" in this thread.

Was proper grounding technique used? Static electricity plus fuel == bad news.

Preflight safely!
 
Dan Thomas said:
Mogas STCs forbid the use of any mogas containing alcohols, specifically ethanol, IIRC. It damages fuel system components, which in airplanes are made of different stuff than in cars. But here in the frozen north, all winter mogas has a little alcohol in it to help prevent fuel system freeze-up, usually less than one percent.
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Ethanol is bad juju when you are talking about "older" cars. The last words the salesman said before we drove off with our new (then) 1986 Dodge van were "Don't put ethanol in this!" Within a year California mandated that gasoline be adulterated with ethanol (oxygenated!). A bit later the reason for not using ethanol in the gas was driven home when I had gas running over the engine block. The ethanol in the gas had eaten the seals in the carb. About $400 worth of repairs later those seals had been replaced with newer material that resisted ethanol. Did California pay for the damage they had caused? Who are you kidding?
 
Bill Jennings said:
The big thing here was recognizing the entire 1st sample (and many after that) was pure water.
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I sumped after annual and the plane had been on the ramp in the rain. The right tank spit out a bunch of water, but it came out as water and fuel. Started about 50/50, then the ratio went down. I was surprised to see that they came out together and not water first, like yours. I had multiple testers of water, but never got a single tester that was just water.
 
Lindberg said:
I sumped after annual and the plane had been on the ramp in the rain. The right tank spit out a bunch of water, but it came out as water and fuel. Started about 50/50, then the ratio went down. I was surprised to see that they came out together and not water first, like yours. I had multiple testers of water, but never got a single tester that was just water.
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Depends on the shape of the sump floor. If the water was occupying part of the area, with fuel the rest, you could get a mix coming out. Try changing the attitude of the airplane such as pushing the tail down and sumping, then pull the nose down and try again.
 
Update: Plane is at Cole Aviation for the annual, this is the mechanics comments regarding the tanks and gas caps:
  • They sumped each tank. A little water in the left tank. Maybe 1/2 inch in sump tool.
  • Gas Cap O-Rings are changed at each annual. Both inner and outer o-rings. Jeff is 98% sure the water we had in tanks was from the FBO fuel tank. Existing O-Rings were in great shape and still had lubrication grease on them.
 
With the GaryV incident and subsequently talking about Walt Meziere, I felt I needed to make an addition to this thread.

In the time period since the last post above on 1/4/2020, the FBO has permanently closed the underground fuel tank and pump that was the source of the questionable water laden fuel load discussed in this thread. The fuel pump was having issues but also the underground tank had no plumbing that would allow sumping the bottom of the tank for water. Let the fuel level in the tank get too low and I can certainly see the opportunity for someone to get some water with their fuel. Closing the fueling station was certainly the right thing to do.

All aircraft must now use the above ground tanks at the opposite end of the apron, and those tanks are sumped regularly.

The end.
 
Bill said:
All aircraft must now use the above ground tanks at the opposite end of the apron, and those tanks are sumped regularly.
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Yup, they sump every morning! When I do my duties, there’s always a good bit of water and brown sludge in the 100LL tank, but very rarely any in the Jet-A tank and I haven’t figured out why.
 
RyanB said:
Yup, they sump every morning! When I do my duties, there’s always a good bit of water and brown sludge in the 100LL tank, but very rarely any in the Jet-A tank and I haven’t figured out why.
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Older tank?? Made of different material?? I dunno, just guesses
 
RyanB said:
Yup, they sump every morning! When I do my duties, there’s always a good bit of water and brown sludge in the 100LL tank, but very rarely any in the Jet-A tank and I haven’t figured out why.
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Just a WAG but the 100 LL is more volatile then the Jet-A . Being an above ground tank it is subject to greater solar heating and cooling . Even with pressure caps it may draw humidity in tank.
 
Southpaw said:
Just a WAG but the 100 LL is more volatile then the Jet-A . Being an above ground tank it is subject to greater solar heating and cooling . Even with pressure caps it may draw humidity in tank.
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Yeah I dunno, however, they are both above ground (100LL and Jet-A) and sit right next to each other, so it shouldn’t make a difference. Thing is, you NEVER see anybody flying a turbine sump their tanks after fueling. The Jet fuel in this specific tank sits for an extended period of time too. It doesn’t sell very fast compared to the AvGas. Definitely something to stroke my chin about…
 
Lachlan said:
Such a great link... and somewhat concerning.
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Why? The tank sumps are not the lowest pointin the system. The engine gascolator is the lowest point. How many 150 owners actually look at THAT fuel and nit just pull the gascolator handle for 3 seconds and move on?
 
pfarber said:
Why? The tank sumps are not the lowest pointin the system. The engine gascolator is the lowest point. How many 150 owners actually look at THAT fuel and nit just pull the gascolator handle for 3 seconds and move on?
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Fuel flows from high to low. Anyone in their right mind doesn’t just sump the gascolator and call it done. Fuel strainers are placed at the lowest point in each tank to eliminate water and debris before they flow down stream.
 
Mooneys have openings cut in the bottom of ribs to provide a channel so

water can flow easily downhill to the sump. If these are blocked when a tank is

resealed water could be trapped uphill until tossed around when airborne.

Somewhat similar to 182 bladder wrinkles. Some Mooneys have an AD to address

this. My bro has an AMOC to check w/o disassembly.
 
In our area, the 100 LL comes from far away, and at a high per truck fee, regardless to the amount delivered so the gas storage is not refilled until near empty. I think the r3efinery is in Huntington WVA.

Jet A is from a choice of several local sources, no truck fee, so kept full.

The amount of air in the tank has a large influence on the breathing in and out, bringing the moisture in, where it cools at night and precipitates to the bottom of the tank.

Sumping is daily here too.
 
Southpaw said:
Just a WAG but the 100 LL is more volatile then the Jet-A . Being an above ground tank it is subject to greater solar heating and cooling . Even with pressure caps it may draw humidity in tank.
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I was an airport manager for some time along with my flight school maintenance and teaching duties. I looked after a 34,000 litre above-ground tank (9000 US gallons), ordering and taking delivery of the 100LL, checking the filters, sumping that tank once in a while. The sumping was done by a hand pump on the top (no bottom drains allowed under Canadian Codes) that had a long pipe that reached down to within about a quarter-inch of the bottom, and forcefully operating that pump would pull out any water anywhere near that pipe. I seldom got more than a cupful, at most, of water even after a month, and the water-detecting paste on the dipstick never found any. This was on the Canadian Prairies where the temperature swings can be large, but admittedly it's a drier climate than on any coast.

100LL has a vapor pressure that is positive even when the fuel is cold. It's always evaporating. That vapor is leaving via the tank vents, all the time. How can moist air get in there, then? Not easily, which is why I seldom found any water. I looked after that tank for 10 or 12 years, and if water had been accumulating I should have been getting more than small bits of it. That tank had explosion vents on it; they were flat caps about a foot across, a one-inch lip all around, covering a flanged pipe sitting about four inches above the tank top. They were just sitting there, no seals, and had several long bolts with nuts on the end to limit the upward travel to a few inches. I think heavy rain would splash water off the top of the tank and up under those vent caps. The same thing that happens to light airplanes with vented fuel caps, or caps with bad seals or gaskets. Blowing snow in a prairie blizzard would also drive moisture into the vents and under the explosion caps. It's not condensation.
 
Bill said:
View attachment 81294 View attachment 81295 View attachment 81296 View attachment 81297 Nice day today, so I though I’d go bore some holes in the sky. Start the preflight, and sump the right tank. Hmmm, that doesn’t look right. Walk out into the sunlight, still doesn’t look right. Sniff. Smells like pond water. Pour across fingers and smell again...pond water. Not a hint of gas. So I pull another, and another, and another after that....

After pulling ten samples of pure water, I say bull chips and start walking to the FBO. They say nobody has complained of bad gas, They give me a bucket, and this is how much more water I pulled before starting to get a little gas. The bucket is 10” in diameter.

This is the fourth pull after starting to get gas, you can see the gas/water line below my thumb. After another 15 pulls or so it looks clean.

At this point I take a careful look around, find no Zulu chasing me with spears, and decide it’s a fine day NOT to fly!

I’ll let the tanks settle overnight and go pull more samples tomorrow and then probably go fly after an extended ground idle on both tanks.

It’s shocking as we’ve owned the plane since 2006 and have never had water in the gas. My partner flew it back from HXD on the 16th, drew from both tanks, put 10 gallons in each wing at the FBO and immediate put the plane in the hangar.

Hmmm
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I'd have to agree with others.. If that's the variables then the only culprit is either rain on the way back on the last flight somehow got in the tanks or the FBO had some contaminated fuel.

If the second part is true then there are some other people out there who got really lucky. Or need to immediately check their tanks as well. Glad you caught it.
 
pfarber said:
Why? The tank sumps are not the lowest pointin the system. The engine gascolator is the lowest point. How many 150 owners actually look at THAT fuel and nit just pull the gascolator handle for 3 seconds and move on?
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You don’t find it a little scary that someone could so easily demonstrate how a very serious amount of water could be “hidden” in a C150 tank, and it didn’t come out the sump drain? Being a 150 owner I thought it was concerning. To humor your ridiculous question, though, I *always* visibly check a fuel sample from both wing tanks, the belly drain and the gascolator before every flight, every time. So, there’s one for you. There might be a few others out there that do it, too. ;)
 
pfarber said:
Why? The tank sumps are not the lowest pointin the system. The engine gascolator is the lowest point. How many 150 owners actually look at THAT fuel and nit just pull the gascolator handle for 3 seconds and move on?
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I do. It’s called following the checklist, or at least a good preflight. I sump each wing, sump the STC belly drain, then sump the gascolator. And one person can reach the 150 gascolator drain and hold a sample cup under the drain without issue.
 
RyanB said:
Fuel flows from high to low. Anyone in their right mind doesn’t just sump the gascolator and call it done. Fuel strainers are placed at the lowest point in each tank to eliminate water and debris before they flow down stream.
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I never said to not check the tank sumps. I said that the tanks are not the lowest point. Words have meaning.
 
Matthew Rogers said:
And one person can reach the 150 gascolator drain and hold a sample cup under the drain without issue.
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In 30+ years of aviation I have NEVER, EVER seen anyone catch the fuel from the gascolator on a 150,152 or 172. The only explanation I ever got (from 4 CFIs) was not standing to close to get your shoes splashed.

Some Pipers have the press in nipple that makes it easy.
 
pfarber said:
In 30+ years of aviation I have NEVER, EVER seen anyone catch the fuel from the gascolator on a 150,152 or 172.
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I do it every time on the carburetor 172's (150/152's are a little bit before my time). My arms are just long enough to reach the drain valve while catching the fuel with the sample cup.
pfarber said:
Some Pipers have the press in nipple that makes it easy.
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Fuel injected 172/182's also have quick drains on the belly. I always poke at all 3 of those with the GATS jar too.
 
pfarber said:
In 30+ years of aviation I have NEVER, EVER seen anyone catch the fuel from the gascolator on a 150,152 or 172. The only explanation I ever got (from 4 CFIs) was not standing to close to get your shoes splashed.
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Odd, I’m curious who you’ve been flying around all that time. It’s been a standard part of the preflight for everyone I’ve observed.
 
pfarber said:
In 30+ years of aviation I have NEVER, EVER seen anyone catch the fuel from the gascolator on a 150,152 or 172. The only explanation I ever got (from 4 CFIs) was not standing to close to get your shoes splashed.

Some Pipers have the press in nipple that makes it easy.
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I am a “medium size - 5’10”” and I can reach it just fine. I’ll even take a video of it just for you so that you can Un-bunch your underpants. Just give me a day or two.
 
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