Water contaminated fuel.

[Beefitarian]

So I have not counted up the number of flights I've done but I have a little over 300 hours. Most, for ease I'll say 200 of them near Calgary because, I know from updating my log book the other day just over 90 are cross country and I only have rented on vacation twice now. Though doing a small flight with a local instructor while on vacation is one of my new favorite things.

Sorry, I tend to ramble. The point..

I was doing a walk around like hundreds of times before. When I took a fuel sample from the second tank, I looked at it and there was a small bubble in the bottom of the little cup. I never found water before. I was actually a little excited about it.

I made sure I took a second sample from the same tank that did not have any noticeable water bubble. Then I pulled the lowest point drain valve for longer than usual before taking a sample from there which looked good.

I mentioned it to someone else who was about to fly another 172 parked near the one I was checking. He made comments to the effect that it would not be unusual. Because it is a warm and very humid place, it seems likely there could be condensation often. I reported my discovery to the instructor and we went flying.

I'm interested in reading comments and opinions from people with more experience.

[robertsailor1]

Main sources of water in fuel are contaminated fuel,condensation inside tanks and a leaking fuel cap in the rain.

[CpnCrunch]

Yes, it's not that unusual to find a SMALL amount of water at the bottom of the tanks. It just shows the importance of doing a fuel drain (and a thorough pre-flight in general!)

[GGCC]

When my Brother and I flew our Citabria on skis off the ice on the Saint John River we had a few 45 gal drums of AV gas stashed and hand fueled from them.

We always did the fuel drain thing and we usually found water droplets, we used wing covers but there were temperature fluctuations....we flew 70+ hours that winter season.

So it happens, summer or winter...........

[Kilo-Kilo]

You will generally get condensation when tanks are left near empty with noticeable temperature fluctuations between day and night. Since it appears you rent planes from FTUs, it is likely that they are topped up on a daily basis and if any condensation were present, the first pilot in the morning would have cleared it.

[L1011]

The flying club I rent from has a policy for the members to only fill the tanks halfway so should the next member want to take his family up it can be done. So a little bit of water from condensation is common. Drain it out and I'm good to go!

[Beefitarian]

When my Brother and I flew our Citabria on skis off the ice on the Saint John River we had a few 45 gal drums of AV gas stashed and hand fueled from them.

We always did the fuel drain thing and we usually found water droplets.

Did you use a chamois? I have heard lots of people talk about needing to be a bit more cautious fueling from drums as there can be more moisture and general contaminants.

[Colonel Sanders]

I am unconvinced that condensation is a major contributor to water in fuel, especially if you live someplace that doesn't get a lot of warm, humid air. Where I live, during winter when the aircraft don't fly much, the dewpoint is often -20C. Not much moisture in the air.

Two ways water gets into your tanks:

1) Leaving the aircraft outside. And it rains. And the seals in your gas caps are old, and let water into the tanks. I have seen a quart of water from this. Drains clear, at first!

2) Water in the fuel. Happens more often than you think. Stays suspended in the gas for a long time. Need to keep draining, and draining.

I have had both of the above, in spades.

[Lost Lake]

Certainly not unusual Way back when I had a 150, it was not uncommon to get water everytime I flew. Not lots, just a few bubbles. Anyone using car gas with ethanol in it may be in for a bigger surprise.

[Colonel Sanders]

Anyone using car gas with ethanol in it may be in for a bigger surprise

Not sure what you mean by that. Ethanol (ethyl alchol aka C2H5OH) is
missible in all proportions with water, and will form a combustible mixture.
This is a good thing. We call it gas line de-icer.

Now, the fuel system may not like the alcohol, but that has nothing to do
with the presence of water.

[Doc]

Water in the fuel "war story" for what it's worth.

Several (Okay, many) years ago, two of us went to pick up a DC3, that had sat for an undetermined time in a farmer's field just south west of Thunder Bay.
We spent a LONG time preflighting this beast. We drained some (not a Hell of a lot) of water from the tank drains. We dipped the tanks. Confirmed we had almost two hours of petrol.
The plan was to fly to YQT, take on gas and head home to Kap.
Now, whenever I get the chance to "tool" around Pie Island, the Sleeping Giant etc., on somebody else's dime, I do it. I didn't that day. Flew direct to YQT. All was well till I lowered the tail, at which point both engines started barking and farting. We had a hard time just keeping them running.
After shut down, we must have drained several GALLONS of water from both wings!
Very lucky we weren't low level half way between the "Giant" and runway 25!
Condensation? Perhaps a wee bit....but the fuel tank caps were for sure the culprits.

[Northern Flyer]

Anyone using car gas with ethanol in it may be in for a bigger surprise

Not sure what you mean by that. Ethanol (ethyl alchol aka C2H5OH) is
missible in all proportions with water, and will form a combustible mixture.
This is a good thing. We call it gas line de-icer.

Now, the fuel system may not like the alcohol, but that has nothing to do
with the presence of water.

This is not really true. Ethanol in fuel attracts and suspends water in the fuel. Then, when the level of water hits a certain point it phase separates. This is why marina's don't carry fuel with ethanol in it. There is allot of info to be found on the deficiencies of ethanol fuel. Another issue with it is a short shelf life, you are looking at about 90 days, and this will be less in an environment of high humidity or moisture. Also it deteriorates rubber at a fast rate.

[Colonel Sanders]

when the level of water hits a certain point it phase separates

Good Lord, man. mogas is easily 10% ethanol. It says so, right there
on the pump. Let's say you have 40 gallons of mogas in the tanks of
your mighty 172. That means you could have 4 gallons of ethanol in
those tanks. That means you could easily suspend 4 gallons of water
in the tanks of your trusty 172, with a 50/50 mix. 4 gallons is a lot of
water in a 172 fuel system. Just how much were you planning on having?!

[Northern Flyer]

Most premium fuel in Manitoba has no ethanol in it. Ethanol on its own in 114 octane. It is mixed into fuel, and increases the octane level of that fuel. I have read allot about Ethanol because my snowmobile was having major detonation issues when running fuel that contained ethanol. It has a resistor that is installed when running fuel with ethanol that retards the timing. I now only run ethanol free premium 91 octane fuel and it runs very well. It's the water absorbing quality that bothers me the most. I don't know the exact ratio of water to ethanol that will cause phase separation. It could ruin your whole day though.

[trey kule]

Well, first the on topic part. My experience is almost identical to the colonol's. Leaky fuel caps and water in the uplifted fuel supply. I have never found condensation to be a big issue, or at least as big an issue as some make it out to be.
As to the chamois, most people who regularly use drums for fueling either have a two filter system, one for particles and the other for water, or, at the very least , one for water . these filters stop the flow of fuel and are very effective, that is if they are the proper ones for aircraft fuel and not mogas. It has been many many moons since I saw a chamois used for fueling, and as modern day "chamois' are mostly synthetic, I would not rely on them.

As far as ethanol goes, I seem to remember we had a Mogas STC on a couple of our planes, and the STC strictly prohibited the use of Mogas that contained ethanol. Maybe I dont recall correctly.

If you are worried about water, the best way is to check before every flight, and when refuleing to let the fuel settle for a bit, and then check it t allow the water to come out of suspension. Years ago, the 185's and a few other aircraft had rubber bladders or liners that would wrinkle and the water would pool there..Part of the prcedure was to rock the wings, let the fuel settle and check it.

As a rule, if you are getting more than a drop or two of water when checking, I would suspect the fuel caps or the fuel supply itself..and the fuel caps will allow morning dew to get into the plane so it does not have to be raining. I have seen water in the fuel problems disappear when new fuel caps were installed. Also, it is always a good idea when using a dealer consistently to ask for their records showing their fuel filter changes, as they need to be changed regularily also. QA folks in companies routinely request this information. Most private pilots and many small companies do not.

The good news, is unlike jet fuel, the water will drop out of avgas if it is left to settle .

[BeaverFixer]

Keep in mind draining the fuel sumps on an aircraft that has been sitting out in below freezing temperatures that you are not going to get any water out. In fact you are probably going to bugger up the quick drain if there is ice in there. Not saying don't check your sumps if it is below freezing. Just be aware if the drain is stiff to push and seems plugged you probably have water "AKA ice" in there. The only real cure then is a warm hangar or wait for above freezing temps.

[GGCC]

When my Brother and I flew our Citabria on skis off the ice on the Saint John River we had a few 45 gal drums of AV gas stashed and hand fueled from them.

We always did the fuel drain thing and we usually found water droplets.

Did you use a chamois? I have heard lots of people talk about needing to be a bit more cautious fueling from drums as there can be more moisture and general contaminants.

Hardly ever used a chamois although always carried one on board, the drum hand pump had a water separator/filter combo attached to the output hose....

note:
about the water droplets, in really cold weather when you viewed the tester contents often you would see it full of little "thingeys" held in suspension....drain it a couple of times and start up, we never had a problem really....the good thing about ski flying in this area is that you have lots of places to land, same for summer water operations...

another note:
fuel caps leaking.....cost my nephew a few bucks to correct the problem on his PA-32 based in Florida.

[robertsailor1]

I had a similar situation as Doc.
I owned a Luscombe 8E and found out the hard way that it had poor seals on the tanks. Unfortunately the way this aircraft was set up the sump was not the lowest point in the tanks UNLESS the wings were level so it was able to acumulate quite a bit of water before it would work its way to the quick drain area. The way to deal with this aircraft was to simply lift the tail (kinda hard on a DC3) and drain fuel or water from the quick drain. It did cause me to experience my first forced landing which fortunately was not that difficult as I lived in the flatlands of Alberta at the time.

[Colonel Sanders]

Unfortunately the way this aircraft was set up the sump was not the lowest point in the tanks UNLESS the wings were level so it was able to acumulate quite a bit of water before it would work its way to the quick drain area

I can't believe a certified aircraft could have a fuel system like this, but .... I also remember when the 1984 AD came out on our Maule, requiring replacing plugs with quick drains at the lowest part of the tanks, for exactly this reason. You HAVE to have quick drains at the lowest point of the fuel system, otherwise you can't get the water out!

But back on topic. Replace those old fuel caps, if you park your airplane outside! I personally am convinced that leaky fuel caps are responsible for 1000x as much water in tanks as condensation, which I suspect is an old wive's tale, right up there with flicker vertigo.

[robertsailor1]

I took a Cessna 170 in trade on an aircraft I sold and it sat for several months at the XD tie down area. An inspector for MOT bought the aircraft. When I sold it to him I suggested that he drain the tanks as there wasn't much fuel left and I had drained off quite a bit of water when I checked it out earlier. He said he'd probably do this but the next day I read in the paper that he had an engine failure over Spruce Grove and he was made out to be the hero because he had in fact done a decent job in force landing it. Later it was revealed that his fuel was water contaminated. Never heard from that fellow.

[hazatude]

You're going to get water in fuel and never take your checks for granted. The most important thing is to remove it. Keep sumping until you get a clear sample.

[.Ben]

in my 4.3 hours of total flight time, i have checked for water a total of 3 times and so far its always been clean and clear

im waiting for the day when i can say AH HA! there you are water!