How much water in the tank is too much ?

[OR75]

http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20130819X52423&key=1

 

 

My aircraft is practically always hangared and only occasionally sees rain or a wash rack.and I rarelly find even traces of water

 

Still I am wondering how much water in the tank it would take to stall an IO-360

 

 

  

[M016576]

Over a half gallon- the pickups are well above the low point of the tank. If I sumped out more than 2 full cups, I'd continue to sump until no more water, then put a container beneath the gascolator and sump a couple cups of fuel out of that, checking the gascolator sump for water as well.

[carusoam]

There are two main sources of water, rain and...

(1) Leaky O rings, know that there are two per cap.

(2) Rusty Mild steal "filler necks". The shaped sheet metal that the cap fits in. The stress of shaping causes them to rust through above the level of the seal. Leaving them open to the atmosphere.

If you consistently get water in your fuel sample, do something about it. Today....

I had the rusty part problem in my '65 C.

The offending parts can be swapped out.

Best regards,

-a-

[nels]

Its funny this topic comes up. We had water in the tank of our 177rg last week. I think it came from the fuel truck. We drained plenty out of both tanks but even after we thought we had it clean we were able to move the wings up and down, rocking the plane, and we got lots more out.

Here is another question, is there any sort of fuel drier additive that could be used on occasion to dry out the tanks completely. Ok, I know alcohol is a.no no but so is water in the fuel lines when you bank the plane or hit turbulence. The incident with our Cessna sure concerns me.

[jetdriven]

If the cap is cocked even slightly and it sits in the rain, it can admit gallons of water in a rainstorm. There was just a thread on here where a 231 owner drained gallons out of his plane because of this.  We had the line boy in FLL take his palm and attempt to hammer the tab down on our 2500$ fuel caps because it was cocked and wouldnt close the tab. Solution, never let anyone reinstall the fuel caps but you.

[Jamie]

Or, apparently, even fill the tank for you.

 

Last flight, I had the right tank topped off. I noticed on the way home the right tank was idicating half full, even though I'd visually verified it was full. I'm going to try burning that tank down and see what happened. It was fine before the line boy topped it off.

[1964-M20E]

Several years ago I was renting a C152 (before I owned a Mooney) and during the pre-flight I drained a number of fuel cups full of water from the left tank.  The right tank was fine and the collator had water in it as well.  After I was satisfied that I had gotten the water out I went on my flight and had no issues.

 I shook the plane several times and got more water.  The best part of it or maybe the worst part of it the plane had flown earlier that day.

 

So how much water is too much as long as you can see the water in the sample cup I’d keep sumping the tank.  Then I’d drain the collator for about 4 to 8 seconds.

[jlunseth]

Isopropyl is fine.  We often use it in the winter here.

[John Pleisse]

No amount is acceptable. Most of the departure accidents from water contamination occur right after the wings bank for a turn out or on course. This is what's insidious about it. You can do a full run up, depart and not detect it until the wings rock.

[201er]

I agree with John.  Any water in the tanks at all is too much.  The thing is, if a little can get in, so can a lot.  It just takes longer.

 

I have never found so much as a drop of water in the tanks of any airplane that I have ever owned, although I do remember that it was commonplace in the Cessnas that I used to rent when I was getting my license.

 

Jim

NEVER let that make you get complacent. I've never had water in my Mooney until I did! Luckily I had learned to be diligent checking for water in Cessnas and continued the practice. Just one day one of my O rings was shot and after a rain storm got a ton of water. It was at night. I sumped a sample and it all looked uniform (usually when a little water you see the bubbles so I'm looking for variation). Under my red head lamp I couldn't assess the color but I sniffed it as I was taught. It didn't smell pungent enough so I began to doubt. I shot my white light on it and it was looking more clear but still can't tell easily at night. So I sumped another tank for comparison and the new stuff immediately floated and demonstrated the color difference between gas and water. I continued to sump about 6 cups out of the tank till I hit gas gain. Got the ring changed on the cap and all was fine. You won't know your rings are bad until you find a cup of water!

[201er]

You wanna know how I know my Mooney's a she?

[Steve65E-NC]

       I agree that a short taxi out and brief run-up will not revile the problem.  One evening I taxied about 150 yds before the problem showed up with an adrupt engine stop. I had pulled each tank separately with no meniscus apparent. 

 

     Since that time, I pull a cup on the right tank, clear any obvious meniscus with more pulls.  Then I set the half or third full cup on top of the cowel and check oil.  On the other side I pick up the cup and add the pull from the left tank.  I figure it unlikely that both tanks are full of water.

 

     On the other hand I also find that smell and beading on asphalt are reliable indicators.  Water beads, fuel soaks right in.

 

    I basically do three walk arounds.  The first just removes bird/insect/prop-padlock guards.  The second checks fluids.  The third is more of a stand-back "will it really fly" check including freedom of control surfaces, tires, prop and mental readiness.

[Shadrach]

No amount is acceptable. Most of the departure accidents from water contamination occur right after the wings bank for a turn out or on course. This is what's insidious about it. You can do a full run up, depart and not detect it until the wings rock.

This is good incentive to keep the ball centered!  I agree with you, any water is too much water. Seriously though, in a Mooney it would take an obscene amount of water in the tanks to get to the fuel pick-up...even in an uncoordinated knife edge. Under normal flight regimes we're talking gallons of water, not ounces.

[201er]

How about uncoordinated + turbulence? How many drops of water does it take going through the fuel line itself to stop the engine? Or will the windmilling prop force it to clear itself out when fuel delivery resumes?

[Shadrach]

I don't think it's the turn out or turbulence.  I think it's pitch.  The pick up is in the aft section of tank and it is inches off of the tank bottom. In a level attitude there is a lot of surface area for water to spread out and it would take loads of the stuff to get to the level of the pick up. Pitch up to VX and suddenly everything comes sloshing back to the rear of the tank and the volume is confined to a much smaller area. It would still take a $hit load to stall the engine... way more than a cup.

[Shadrach]

That is probably true, but where there is a will there is a way.  A gentleman here where I live a few years ago apparently smoked some crack and then took off after inadequently sumping the tanks on his K model.  He died a few minutes later. 

I always wait until I'm established in cruise before I start smoking crack. Anything else is just poor airmanship... 

[201er]

Do we need a poll of when you guys like to crack open your stash in flight?

[AlanA]

I use to drain a small bit of water from my right tank until I replaced the O rings.  Did it myself.  Very easy.  Very inexpensive.  Good posts on the site already on how to do it.  Now never a drop.

[Shadrach]

I vote after cocktails...

[jetdriven]

I always wait until I'm established in cruise before I start smoking crack. Anything else is just poor airmanship... 

 

It takes two hands to hold the pipe and the lighter. Another vote for the autopilot with altitude hold. Also useful for other extracurricular activities. Safety first!

[Marauder]

Or, apparently, even fill the tank for you. Last flight, I had the right tank topped off. I noticed on the way home the right tank was idicating half full, even though I'd visually verified it was full. I'm going to try burning that tank down and see what happened. It was fine before the line boy topped it off.

Sometimes the sender float gets stuck. I have had this happen a few times over the past 22 years.

[nels]

Isopropyl is fine.  We often use it in the winter here.

I asked the mechanic about the use of alcohol in the tank and specifically isopropyl alcohol; his comment was absolutely not.....no alcohol of any kind. Says it ruins the tank seal and other plastic or rubber components. Anybody know if what he says is gospel or is he just spouting off?? I know I would feel a lot better if I could put a can of "dry gas" In the tank after I purged all the water I possibly could.

[Shadrach]

I asked the mechanic about the use of alcohol in the tank and specifically isopropyl alcohol; his comment was absolutely not.....no alcohol of any kind. Says it ruins the tank seal and other plastic or rubber components. Anybody know if what he says is gospel or is he just spouting off?? I know I would feel a lot better if I could put a can of "dry gas" In the tank after I purged all the water I possibly could.

Long term exposure to Iso is not good for seals. However, in the quantities to which I assume Jlunsethit is referring (we're talking alc to avgas ratios of 1:>2000 or .05% or less), the risks are pretty minimal. I've never used it, but know of many in the PNW and Alaska that use it when needed.

Politely ask your MX to read the note after Table A1 on leaded aviation fuel in Lycoming Service Instruction 1070R.

"Isopropyl alcohol in amounts not to exceed 1% by volume can be added only to aviation fuel (not automotive fuel) to prevent ice formation in fuel lines and tanks. Although approved for use in Lycoming engines, do not use isopropyl alcohol in the aircraft fuel systems unless approved by the aircraft manufacturer."

As for Mooney, I believe the newer birds actually have 3% isopropyl as the max percentage allowed listed in the POH...

[kellym]

Fine in theory, impossible in practice. Regardless of whether leaking O-rings  or other source of water in tank, You cannot drain it all out of the quick drains.

Fortunately, I have not had trouble with water in both tanks, but once it has gotten in a tank, with thorough draining, it takes burning several tanks worth of fuel from that tank before you won't find any at next check. If I find it, I drain until clear, then take off on the other tank, and as soon as at safe altitude, switch to the contaminated tank and run on it until near landing, then go back to good tank. Repeat that for 3-6 flights before that tank will again test clean.

Have greatly reduced chances of rain getting past the cap seals by replacing standard MS Orings with fluoro-silicone seals that are much more durable.

http://www.csobeech.com/fuel-caps.html

Yes, many Beech products use exactly the same caps with same issues.

No amount is acceptable. Most of the departure accidents from water contamination occur right after the wings bank for a turn out or on course. This is what's insidious about it. You can do a full run up, depart and not detect it until the wings rock.

[mike_elliott]

 

Have greatly reduced chances of rain getting past the cap seals by replacing standard MS Orings with fluoro-silicone seals that are much more durable.

http://www.csobeech.com/fuel-caps.html

Yes, many Beech products use exactly the same caps with same issues.

 

While the blue fluoro O rings certainly are more durable, and look pretty, They don't do any better job than a standard O ring in good shape in keeping out the water. If one wants to spend $40 ea for the large o rings, then by all means do. Personally, I change them every year, service and inspect the caps while I am at it whether they need it or not. Cost is about $3/ cap for materials including the dow lubricant vs about $45 per that will last about 5 to 10 times as long.

YMMV, but I do like the cool blue look Now if they were only 2x the price, or if I kept my plane on a tie down..well, that would be different