Had a lot of water in my fuel

[FloridaMan]

I sumped several cups of water before seeing a thin layer of blue on top. The FBO didn't properly install my fuel cap and I had their line manager witness that it wasn't installed correctly. I go to sump the tank and I had a cup of water with a bead of blue in it at the top. The other tank (right-side, which I didn't take fuel in) was fine, but nearly empty. I had them add about 8 gallons to the "good" tank. After sumping the left until the fuel came out blue, I started the plane on the right tank and taxied it about a mile doing hard S-turns through the taxi, sumped the left into a GATS jar until the little bit of water that the hard taxi shook free was no longer there for a few full jars. Then I sumped the gascolator for each tank for one minute each, twice, and there was no water. 

Then it rained hard again. I went and sumped both tanks after the rain and the fuel came out uncontaminated. I took off on the right (good) tank, climbed to 3000ft above the field, did some hard maneuvering, switched to the left and did some harder maneuvering, switched back to the right, landed, sumped again; things still came out blue and appeared uncontaminated. Departed with my passengers, taking off on the right tank again and switching to the left enroute. The engine never stumbled after all of that so it seems like I probably took care of all of the water, but is there anything else that I should do? Is it worth having a mechanic pull the drain and having them completely empty that wing? 

Edited November 3, 2016 by Antares

[Robert C.]

I had a leaky O ring/seal last year resulting in a large amount of water in one of the tanks and just had it replaced (them actually, the shop replaced the O rings for both tanks). No trouble afterwards and my AP didn't recommend additional testing. Reads to me like you did a very thorough job checking that you were safe before heading out.

As Anthony likes to say: just another PPL here, not an AP myself. 

Robert

 

[carusoam]

Talk with you mechanic about fuel additives that can adsorb water.  Alcohol is one of those things.  It used to be called dry gas...

remember that?  From a long time ago...

All that unusable fuel below the drain could be something other than useable fuel.

Check with your mechanic to find a proper dry-gas and how to use it properly...

PP advice only. Not a mechanic...

Best regards,

-a-

[M016576]

Or just run the

Just now, carusoam said:

Talk with you mechanic about fuel additives that can adsorb water.  Alcohol is one of those things.  It used to be called dry gas...

remember that?  From a long time ago...

All that unusable fuel below the drain could be something other than useable fuel.

Check with your mechanic to find a proper dry-gas and how to use it properly...

PP advice only. Not a mechanic...

Best regards,

-a-

Or just run the tank low, and unscrew the drain and let whatever's left in there drain out.  Then torque the drain back on.  Or If your dump is old and sticks a little, replace it- they are only about 20 bucks.

careful, though- the torque spec is in Inch-pounds... Not foot-pounds.  It doesn't take much to shear the whole thing apart.

[Vance Harral]

Great job on being so thorough with your checks.  Given all that you've done, the amount of water remaining in the tank may not be zero, but it's almost certainly unmeasurably small.

We got water in our tanks a few years back and were concerned.  But in the end we didn't do anything other than sumping until the tank and gascolator drains showed no more evidence of water.  We talked to an experienced mechanic about it at the time.  His take was that a tablespoon or two of water sloshing around in the very bottom of a tank after sumping wasn't going to make the engine quit, even if small portions made their way to the pickup lines.  He said you have to pick up a pretty big slug of water for the engine to noticeably quit making power.

That still sounds a little cavalier when I put it in writing, and I don't mean to minimize the concern.  But it does make some common sense.  Water passing through the fuel system isn't destructive by itself, it's just not combustible fuel.  How big of a deal it is depends on how much water there is.  A few drops that pass through the system in under a second aren't going to ruin your day.  A half gallon that takes 3 minutes to flow is obviously a different story.

[DXB]

1 hour ago, Antares said:

 After sumping the left until the fuel came out blue, I started the plane on the right tank and taxied it about a mile doing hard S-turns through the taxi, sumped the left into a GATS jar until the little bit of water that the hard taxi shook free was no longer there for a few full jars. 

I took off on the right (good) tank, climbed to 3000ft above the field, did some hard maneuvering, switched to the left and did some harder maneuvering, switched back to the right, landed, sumped again; things still came out clear. 

Interesting - thanks for posting - I would not have thought to do these two steps - good standard practice in this situation?  And by "came out clear" in the last sentence you mean no further water?

[1964-M20E]

I had a similar experience about 5 yeas ago with a 152 I was renting.  Once I was comfortable with getting no water while sumping the tanks and the sump I went flying but I was by myself.

That my friends is why we check.

 

 

 

 

[bradp]

I had a similar experience with a line crew that fueled and didn't put cap on flush.  Then it rained.  A lot.  For two days straight.  I was pissed, but just matter of factly showed the line crew the cap and water and told them that's really important for them to follow up internally as that could have killed me.  I left it at that and didn't demand anything.   They got it.  

I sumped until it ran blue, made it "pee" for longer than usual to make sure line was clear to the gascolator.  I then grabbed the edge of the wing and rocked back and forth to agitate fuel to hopefully get any sunk water back toward the sump pickup.  Other times when I've had water contamination this method has worked well.  Similarly fueling can "push" collected water towards the low point.  Let sit for 5 min and returned to the beginning to do it again.  I took off on the opposite tank of course and only switched tanks when I was overhead an airport.   

Look at raptors fuel tank thread and note where the pickups are compared to the sumps and what degree of safety margin that provides with regard to tank contamination.  

I think you did a super thorough job of ensuring water would stop your prop.  

The question is how thorough for safety versus personal comfort and what is required now.  

I'd be apprehensive about chemical means to remove water with regard to tank sealant and engine ingestion of alcohol.  Isopropyl takes apart tank sealant pretty well.  Mechanical means (i.e. draining a tank completely) would be my preferred method if that was needed at all.  You may be able to reach the onboard aft corner with a small hose to siphon by the cap if you're a lucky shot or the sender from within the cabin (minor surgery required).   

Back to my original story. For me all fueling is now done supervised as much as possible.  If I want to leave the FBO in a hurry, I tell them I'll let them know about fuel on the morning of departure.  If I can't be there physically, and have them do it unsupervised, the chance of the cap being off for more than an hour on the day of departure is minimized. If it's raining I'll watch them do it. 

With every FBO I put two things down in writing   these days. 

1) ensure fuel caps are totally flush before securing. 

2) if the plane needs to be moved,  13-deg steering limit needs to be strictly adhered to.  

[Guest]

Isn't supervising the refuelling and installation of the caps a pilot in command responsibility? 

Clarence

 

[FloridaMan]

2 hours ago, DXB said:

Interesting - thanks for posting - I would not have thought to do these two steps - good standard practice in this situation?  And by "came out clear" in the last sentence you mean no further water?

Yes, blue. I'll revise my original post. 

[FloridaMan]

The way I see it is that there are a number of fatal accidents regarding Mooneys and water in the fuel; especially in older Mooneys, but the newer ones aren't immune either. Water droplets stick behind rivets, baffles and areas where sealant might block areas in the tanks, which is the reason for the extreme thoroughness with the S-turns on the ground. 

http://www.kathrynsreport.com/2015/07/engine-makers-blamed-for-fatal-plane.html

[ArtVandelay]

Isn't the gasolator suppose to separate water from the gas? Obviously a last resort but can you check what comes out when you drain the gasolator?

[carusoam]

From my C experience, and tying down out doors, and having rain water in the tanks all the time... the fuel necks rusted holes all the way through.

you can sort of rely on the gas collator to separate out the water, it will do that sort of well.

Being an engineer has strengths and weaknesses.  Having no water in the system is still better than having some water in the system.  Even when there are technical ways to handle it...

the water, and rust bits would collect in the separator.  The 'stainless' shaft that the valve/pull ring are attached to had also become weakened by corrosion after sitting in water for so long....

There are so many unknowns or lesser knowns. It is better to take care of the ill knowns than rely on the back-up plan to work properly.

Shared experience...

Best regards,

-a-

[M20F-1968]

I am envisioning some sort of rubber cover, perhaps about 12" in diameter, that has some sort of cemented on plastic or other material piece that is shaped to snap into a recess in the fuel cap to act as a cover for the fuel caps to as a safeguard (second line of defense) when parking outside.  I was thinking that a small plastic part could be made that could snap into the recess of the fuel cap, be glued to a sheet of rubber or some other similar waterproof material, and be used to keep water out of the tanks.  Of course the first line of defense is to keep the caps, O-rings and filler neks in excellent conditions and the caps on correctly.  Just being OCD about this one.

[M20F-1968]

Thinking maybe the small connecting part attaching to the fuel cap could be made on a 3D printer.

John Breda

[Guest]

Some form of sticky silicon mat to cover the filler port?  I saw this at Oshosh this year, something like this material might work.

http://grypshon.com

Clarence

 

[FloridaMan]

43 minutes ago, M20F-1968 said:

I am envisioning some sort of rubber cover, perhaps about 12" in diameter, that has some sort of cemented on plastic or other material piece that is shaped to snap into a recess in the fuel cap to act as a cover for the fuel caps to as a safeguard (second line of defense) when parking outside.  I was thinking that a small plastic part could be made that could snap into the recess of the fuel cap, be glued to a sheet of rubber or some other similar waterproof material, and be used to keep water out of the tanks.  Of course the first line of defense is to keep the caps, O-rings and filler neks in excellent conditions and the caps on correctly.  Just being OCD about this one.

I was actually thinking of taking a rare earth magnet and casting it in the middle of a silicone disc. Though gluing two jar openers together with a magnet in the middle would have the same effect. I'm pretty sure the fuel cap centers can hold a magnet. 

The other option I've considered is just taking blue painters tape and taping over the entire cap when parked down for a while. This is also useful for fueling and giving ramp instructions. For instance, you could write "Sunday Departure" and tape it to the prop. 

Edited November 4, 2016 by Antares

[DonMuncy]

I have a pair of fuel cap covers (sold some time ago by the Mooney Miser) They are great when you have to leave your plane outside when away fro home. If anyone has any interest in building themselves a set, let me know. 

 

[nels]

Libricating the o rings and also lubricating the locking lever on the top of the cap really helps properly seating the caps.

Also, when looking through my 201 manual, it mentions that it is ok to use some alcohol additive to the fuel for winter use to prevent fuel line freeze. I was glad to see that was acceptable. I would think it is a good final touch after seeing water in the fuel.

 

 

[DAVIDWH]

My experience with H2O came after a routine wash job done by the FBO.

I was pretty sure the cup would never turn blue.

Replaced O rings on cap and no more angst.

Incidentally, read somewhere that sumping after a fill is useless as it may take hours for the water to filter down to the sump.

Does anyone know how long it really takes?

[ArtVandelay]

Sounds like a good YouTube video: pour avgas into tall glass, add water, stir....watch what happens.

[carusoam]

Sampling after a fill is not perfect...  try not to confuse the extreme 'useless' with what can happen...

Water settles quickly in a jar or sample cup.  In a plane it can get hung up in a lot of places until the plane gets moved... tiny rib holes are in there between tank sections. Water can get hung up pretty far from the drain.

water can stay below the level of the drain. This is why the fuel additive is the next method of getting the remaining water out...

The purpose of sampling is to check for water.  Most significant water doesn't come from fueling.  It is also to check that 100LL was delivered.  Not jet fuel.

Take the jar experiment to the next level.... see how much additive it takes to absorb the water....

It is a molecule by molecule kind of event.  If a quart of water is in there.  It is going to take a lot of additive over a few fills to remove it all...

Definitely follow the instructions on the bottle.  Don't decide to go beyond the limits because it sounds like a good idea...

PP ideas only, I am not a mechanic...

keep sampling, check the color against the white back ground, smell it if your nose still works.  If there is no visible water AND you can't see the blue color.  Spit into the fuel in the sample cup... it has an obvious result...

move the wings with intention, sample again....

Best regards,

-a-

 

[nels]

How does the alcohol in fuel work to lesson the water or ice danger. Doesn't it wet the fuel so to speak so the water actually mixes with the gasolene instead of all the water hanging together?

[carusoam]

Nels,

Picture a long molecule.  On one end it has an OH group (the alcohol group) on the other end, nothing but CH₃...

a water molecule really likes hanging with the OH group and the 100LL doesn't mind hanging with the CH₃ group. So, essentially, having that one molecule will allow a water molecule to be able to mix with all the other fuel molecules...

OK, that is a bit simplified.  You would need to picture a 3D model of how that really works, but that is the basic chemistry that allows dissimilar materials to mix with one another.

this kind of gives a feeling that a molecule of water could be helped to be absorbed by a molecule of alcohol, but that is probably not the real case.  It may take enough alcohol groups to surround the water molecule to have it blend in.

Then there is mixing involved.... getting the water broken up into individual molecules to allow it to be surrounded by the alcohol molecules.

The fuel additive may be a specific alcohol that works best for the application.  Using the minimum chemistry to blend in the water...

under less than ideal conditions, water droplets can be surround in a similar way as I described at the molecular level.  This may cause tiny water droplets to be included in the fuel flow to the engine. Too large of a droplet, it's density would have it sink to the bottom of the tank.

This is why following the instructions has some extra importance.  Mix the additive into the fuel while filling is probably a good idea... distributing the additive around at the molecular level is probably better than having it poured in first and mixing with the water...(?)

I have a lot of mixing experience, but not the chemistry that often goes with this. We have a couple of chemists around here that would be better than me to give specifics...

PP thoughts only, not a chemist or fuel engineer...

Best regards,

-a-

[mooniac15u]

12 hours ago, carusoam said:

Nels,

Picture a long molecule.  On one end it has an OH group (the alcohol group) on the other end, nothing but CH₃...

a water molecule really likes hanging with the OH group and the 100LL doesn't mind hanging with the CH₃ group. So, essentially, having that one molecule will allow a water molecule to be able to mix with all the other fuel molecules...

OK, that is a bit simplified.  You would need to picture a 3D model of how that really works, but that is the basic chemistry that allows dissimilar materials to mix with one another.

this kind of gives a feeling that a molecule of water could be helped to be absorbed by a molecule of alcohol, but that is probably not the real case.  It may take enough alcohol groups to surround the water molecule to have it blend in.

Then there is mixing involved.... getting the water broken up into individual molecules to allow it to be surrounded by the alcohol molecules.

The fuel additive may be a specific alcohol that works best for the application.  Using the minimum chemistry to blend in the water...

under less than ideal conditions, water droplets can be surround in a similar way as I described at the molecular level.  This may cause tiny water droplets to be included in the fuel flow to the engine. Too large of a droplet, it's density would have it sink to the bottom of the tank.

This is why following the instructions has some extra importance.  Mix the additive into the fuel while filling is probably a good idea... distributing the additive around at the molecular level is probably better than having it poured in first and mixing with the water...(?)

I have a lot of mixing experience, but not the chemistry that often goes with this. We have a couple of chemists around here that would be better than me to give specifics...

PP thoughts only, not a chemist or fuel engineer...

Best regards,

-a-

I'm one of the chemists and I think that was an excellent description. 

@nels Large volumes of water should be removed by draining it off the bottom.  Small quantities present either in the bottom of the tank or in fuel added to the tank are what you want to address with alcohol.  You are correct that it will distribute the water throughout the fuel but that is what you want.  It is far better to distribute the water than to feed a high concentration to your engine for even a short time.  A few ounces of water distributed across 25 gallons of fuel will not be noticeable.

The alcohol should also have the effect of not allowing the water to freeze in undesirable places like fuel lines.