Check everything every time

[Bennett]

Its my standard practice to fuel my aircraft before rolling it into my hangar. Plenty of time for any water to settle to the bottom; if the fuel truck had any water in its system. Traveling; I am always wary, and I like to fuel early, rather than later. Hangars are expensive, especially near the big cities on the West Coast, but they do protect the airplane well.  Since I generally fly alone, I keep the fuel tanks filled for several reasons - one being to minimize condensation. For those who keep aircraft outside, at Oskkosh I saw plastic covers for fuel caps to keep the water away from the gaskets and the recess in the caps.  Sorry I don't recall the name of the mfg at the moment, but they struck me as a good idea. THe name was something like Stay Sealed.  Don't know if they have a Mooney specific product.  Shouldn't be too hard to find on the web.

[Bennett]

Duplicate

[Steve65E-NC]

Hey, I like the on-board packing or blue masking tape idea.  Thanks.  I have messed with clip on rain covers but can not come up with anything that I like.  I am parked out in the rain only occassionally and enroute.

I have a fuel cup.   I always drain the right, then set a half filled cup on the cowel as I check the oil, then add the initial drain from the left.  

Reason:  One evening at dusk, preparing for a night currency flight, I drained both sides.  No miniscus on either side.  Taxied about 150 yds and the engine quit.  Towed back I again checked both tanks.  The failed tank gave about six cups of pure water before a miniscus appeared.  In the low light I just did not pick up the lack of blue tint.  The other tank was fine.  I first figured out what was going on with a cross check as described above.   I think it somewhat  unlikely that both tanks will pick up water and my method cross checks and reminds.  If any doubt remains, I also do the asphalt beading test. particularly in low light.     

[DaV8or]

It would be an interesting test for one of you guys that is about to do a full strip and reseal of the tanks- Fill the tank with at least half tanks, then pour in a measured amount of water at the filler and take sumps at regular intervals to see how long it takes and how much water actually comes out. Then maybe see if rocking the wings speeds up the water reaching the sumps, or increases the amount of water.

Last, be sure to post your findings here for all of us!

[rob]

Quote: carusoam

If the caps still leak after the O-rings have been replaced....

Check the neck that they are sealing into.  Rust has a tendency to eat all the way through on non- stainless versions...

There are stainless solutions for this serious challenge. 

-a-

[WardHolbrook]

Quote: aviatoreb

I agree with this 100%. Also, remember that it takes a while for any water in the fuel to migrate to the sumps (about 15 to 20 minutes in most fuel tanks) so don't be in a big rush to blast off after fueling. Fuel, wait at least 20 minutes then sump. I learned that lesson the hard way. 

[jlunseth]

I have, or rather had, two very good friends who died in separate aviation accidents decades ago.  There was a common cause in both, and no it was not fuel contamination.  It was that as the PIC, they had relied on someone else to do preflight tasks for them.  One of the mistakes was simply allowing a non-pilot to close a luggage compartment door. 

My number one rule as PIC is "do your own stuff." I only spell it "stuff" for this family oriented forum.  There is no excuse for letting anyone else do your $#!% for you.  If you do your own $#!% then you are not going to be someone else's victim.

[Seth]

You know, that may be why my bladders never had any water contamination in the 1967 F model for the first 1.5 years it was tied down before I put in in a hanger.  The bladder install makes for a much better seal - the new caps right?

The Missile has four caps and I sump now very carefully, even when it has just been sitting inside the hanger and after the sumping discussions we've had on MooneySpace.

As always, thanks to everyone for important bits of information.  Lifesaving information.

-Seth

[richardheitzman]

There is a SB / AD that mandates the change of the O-Rings at every annual or (500?) hours of operation. Check your S&M manual.

If your mechanic is not doing it, chew his a$$ out of not doing it, and get it done. Only use the specified / FAA approved O-rings that are shown in the S&M manual. Do not use any type of aftermarket non-approved O-rings in your fuel caps.

Danb35 I appreciate the advice, but I would also appreciate it if you do not tell people to use non - approved critical parts on aircraft. I would suggest you take those non approved O-rings out of your fuel caps and replace them with the approved parts.

Rich

Quote: danb35

They aren't too hard (and neither they nor the outer O-rings are required to be replaced at any particular interval), but if you replace them with blue flourosilicone O-rings (assuming your A&P is OK with that replacement--mine was), they'll last a lot longer.  A shot of Tri-Flow down the center shaft every now and then will help too.

[carusoam]

Rob and JimR,

Jim answered as what is required for old M20s.  My C rusted, and rough oxidated surfaces always leaked a drop or two after rain.

One day it was a full cup and then some.  A hole opened where the sheet metal was bent/shaped in the neck.

My plane was doomed to the sales yard at that moment.....

Really it doesn't take much to fix that problem, JimR outlined getting the new part insalled, but I preferred more HP, newer systems, modern avionics, leg space in the back, fuel injection, near real IFR capabilities, newer paint... And less money in my bank account.

It turns out my old necks and caps were no longer OEM.  News to me, no record of it either. Plastic caps on a mooney....not OEM, possibly race care mod.

I may have been angry that day.  I bought new OEM caps and gave them to the new owner as a reminder of the work he needed to complete.  He got a set of seat belts too...

Rember, if you don't see a meniscus...spit in the cup,  you should now.

With good seals you should find ice on cold days in NJ.  No ice, water must have gone somewhere....if you find ice, a bag of hot water is the next best way to get the caps open.

I ask the fuel person to leave my caps off.  I am not shy about this situation.  It helps me to remember what I need to do... How full they are, and sump, while I'm there.

The ovation's tanks are always dry, SS fuel necks and good seals are the main reason. No rust, no holes, no water....

Best regards,

-a-

[FloridaMan]

Would it not make sense to leave a sheet of silicon rubber over the gas cap area when you park the plane? You can get 6" squares (in red) for just a few dollars from mcmaster.com. I don't know if it would affect the paint to lay them over the area though. 

[jetdriven]

Flourosilicone blue o-rings are superior to nitrile rubber o-rings. Our bladder-equipped M20J has them as part of the fuel cap change with the bladder kit. We replaced them this year as a precautionary measure, but AFAIK they have never been changed, did not leak, and they were 20 years old. 

[danb35]

Quote: richardheitzman