HELP and input needed, quickly, sigh... leaky tanks

[joekinnc]

Hey Folks - 

Me again - same subject - apologies in advance but I do need the wisdom of the forum with some urgency please.  So I took delivery of my new to me 67 M20F... delivery went okay overall (12/2/18)- plane landed with a throttle linkage issue and a generator bolt issue (still awaiting the details and the BILL for that - anyway...).  Do to some other delays, weather, paperwork etc - I have not been able to fly the plane, not once.  The plane was towed to the repair hanger to fix the throttle and generator bolt issue.  And so now - 3 weeks after delivery - I believe the tanks are leaking - the plane was topped off in prep for a flight on 12/16 - flight was a no go - returned to plane on 12/22 and tank was 2-3" low.  No obvious blue streaks, no big puddle on the ground etc.

The seller of the plane has been wonderful so far.  The tanks were patched on 10/16/18 - this is ~ the 3rd+ patch on the tanks.  The previous delivery of the plane was delayed in fact so the seller could patch them (my previous post) at his cost.  (Find not necessarily repair)

Net net - my question is this - HOW do I determine if they are truly leaking - and where from - and is this something your average A&P can do?

The seller and I (again, a really good man) are in a bit of a he-said she-said deal.  I will not fly the plane or accept it until right, he feels he delivered a plane that was OK - but who knows - a slow leak could have been present during the entire delivery, yes?  I feel we should split - 70/30, 60/40, etc the cost of a full strip and reseal.  OR - he can just take the plane back - I'm in NC - he is in UT and says this is not an option - at all.

So - power of the FORUM - please respond - how do I track down this gremlin of an issue and how do we make this right?

THANK you all - so so - much... I really want to fly the plane!

Joe K.

Edited December 27, 2018 by joekinnc

[Yetti]

There is a inspection panel on the leading edge bottom about 1/3 away from the cabin.   Pull that cover and look for fuel stains.   Fuel tank covers are flush mounted from the inside.  Know the difference before proceeding.   Also is there a fuel smell in the cabin after being closed up?  That would just be a sender that is behind the lower side panels in the cabin.   Cell phones make pretty good inspection devices.....  but they are not intrinsically safe, so be careful with fumes.

[MrRodgers]

 

 

First and foremost congratulations on your new to you M20F. In reading your comment above That you topped off the tanks and then went to fly but didn’t,I can only tell you what my experience has been.

 

I’ve got a 67F as well. When I top off the tank’s prior to a flight the fuel takes about 8-10 minutes to settle through any baffles in the tanks to the lowest levels. I top off the tanks and the fuel settles again. This could make it appear that there might be a leak if you didn’t stand over the opening and watch and listen to the fuel move down. I’ve been able to add nearly 5 gallons more from where it originally looked topped off in each tank. I suggest filling to the top and waiting. You might be surprised how much fuel settling you have.

 

 

 

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[Ragsf15e]

2-3” down from full should leave significant blue stains somewhere.  Significant. You sure it was full, level, and nobody had access?

[takair]

Fill it up and park it in a hangar over night....same spot.....don’t move it.  If it leaks, there should be obvious stains or cabin smell, as others have said.  Filling our planes to the top can be a slow process.  If filled quickly and then capped without settling, you can easily miss a few inches.  The last couple of gallons may need to be added at a trickle.  As Rags said, you would need a notable leak to drop that much in a couple of weeks.

[LANCECASPER]

2 hours ago, joekinnc said:

Hey Folks - 

Me again - same subject - apologies in advance but I do need the wisdom of the forum with some urgency please.  So I took delivery of my new to me 67 M20F... delivery went okay overall (12/2/18)- plane landed with a throttle linkage issue and a generator bolt issue (still awaiting the details and the BILL for that - anyway...).  Do to some other delays, weather, paperwork etc - I have not been able to fly the plane, not once.  The plane was towed to the repair hanger to fix the throttle and generator bolt issue.  And so now - 3 weeks after delivery - I believe the tanks are leaking - the plane was topped off in prep for a flight on 12/16 - flight was a no go - returned to plane on 12/22 and tank was 2-3" low.  No obvious blue streaks, no big puddle on the ground etc.

The seller of the plane has been wonderful so far.  The tanks were patched on 10/16/18 - this is ~ the 3rd+ patch on the tanks.  The previous delivery of the plane was delayed in fact so the seller could patch them (my previous post) at his cost.  (Find not necessarily repair)

Net net - my question is this - HOW do I determine if they are truly leaking - and where from - and is this something your average A&P can do?

The seller and I (again, a really good man) are in a bit of a he-said she-said deal.  I will not fly the plane or accept it until right, he feels he delivered a plane that was OK - but who knows - a slow leak could have been present during the entire delivery, yes?  I feel we should split - 70/30, 60/40, etc the cost of a full strip and reseal.  OR - he can just take the plane back - I'm in NC - he is in UT and says this is not an option - at all.

So - power of the FORUM - please respond - how do I track down this gremlin of an issue and how do we make this right?

THANK you all - so so - much... I really want to fly the plane!

Joe K.

In your second sentence above - you took delivery - you accepted the airplane. In your fourth paragraph you say that you will not fly the plane or accept it until it's right. Which is it? Have you taken delivery and exchanged money? Or are you still negotiating?

 If you have taken delivery, prior to this happening any of these items should have been discovered in a good, thorough (expensive) pre-buy.  That would have been the time to discuss any findings. It is not his responsibility to do anything if you have accepted it and he is paid. You bought a 51 year old airplane as-is, with no warranty. Now. .  if you haven't accepted the airplane and haven't paid him, then it's your option what you do. You can walk from the deal or tell him what you can live with.

If it's a done deal, switch sides with him for a moment, if there had been no problems with the airplane, and now weeks later he comes back to you saying he should have asked more for it than he did, would you feel obligated to write him a check? No, a deal is a deal.

By the way, if the tanks are leaking, there will be blue stains and, most of the time, a smell of fuel in the cockpit. The fact that the fuel is 2-3" lower doesn't mean there's a leak. It could be the way the airplane is sitting now compared to when it was filled, or someone may have "borrowed" some fuel from you.

 

[rbridges]

During winter months, you should see blue since evaporation occurs more slowly.  I never saw a drop in the fuel level, but I saw blue leaks and I could smell fuel in the cockpit.  The staining wasn't observes during the summer. 

[gsxrpilot]

What @LANCECASPER said.

• If you paid for the plane and took delivery, it's your problem and no one else's. If you took delivery but haven't paid, the seller is an idiot. 
• A fuel leak is evidenced by blue staining on the outside of the tank. The level of fuel in the tank is no indication.

[Bob_Belville]

I agree that without smell or stain it is unlikely you have a leak. And if both sides seem to be down a couple of inches it is more than likely they were not filled. Further, unless you're headed out on a long trip it is good practice to not cram in the last gallon, particularly if the weather is warm

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[EricJ]

I'll just +1 that if there's a leak there'll be blue staining somewhere and/or fuel smell.   If the cabin has been closed and there's no fuel smell when you open the door, that's good news.   Even if there is, it's not necessarily bad news.

There are guidelines published by Mooney regarding leaks, and they're evaluated by how much staining there is on the ground under the airplane.   Unless it's actually so bad that it's dripping on the ground and leaving stains, I wouldn't get too alarmed just yet.

 

[Bob_Belville]

Where in NC are you? We have a Mooney SC at KMRN. Lynn @agl should be able to ease your concerns if you bring the plane by.


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[N201MKTurbo]

Just the opposite of what you indicate is the normal course of events. Significant staining with little or no detectable loss of fuel. I can't think of any way that much fuel leaked without major indications of a leak.

Are you the one who fueled the plane? If not how do you know how much fuel was in it. I asked an FBO to top off a Rocket with long range tanks once. I made them come back and put the additional 10 gallons in to actually top it off. 

[M20F-1968]

I have a 68F and am well aware of what it takes to put a plane of this age into a condition that is acceptable (although I went much further than that since mine was taken apart when I bought it).  

You will not get the tanks to be in the condition you want them to be if they have never been stripped and resealed since new.  You just bought the plane, and I assume it fits what you need and intend to keep it.  Then, do the work right and strip and reseal both tanks.  You may even want to install the long range tanks which gives an F exceedingly long legs.  

Paul Beck at Weep No More is the guy you should call.  Figure out what you want the plane to do and what capabilities you want and make it happen.  If the airframe is a great specimen, without any serious problems, you will have a great plane in the end. 

John Breda

[Trailboss]

What was the ambient temperature on 12/16?  What is the temperature on 12/22?  I've had issues the other way...filled tanks outside at 30F to full, then parked in a heated hanger...next morning, when I opened the fuel tanks...110LL all over the wing.

[Marauder]

What was the ambient temperature on 12/16?  What is the temperature on 12/22?  I've had issues the other way...filled tanks outside at 30F to full, then parked in a heated hanger...next morning, when I opened the fuel tanks...110LL all over the wing.

The expansion & contraction phenomenon is real. I can fill my plane to the top at 50° outside air temp and see it go down an inch or more by the next morning with the temps in the high 30s.

Same with filling the tanks on a cooler day and storing in a warmer hangar.


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[Hank]

I generally fill mine to about an inch below the top, to allow for thermal expansion without losing fuel out the overflow vent.

[jaylw314]

15 hours ago, joekinnc said:

Hey Folks - 

Me again - same subject - apologies in advance but I do need the wisdom of the forum with some urgency please.  So I took delivery of my new to me 67 M20F... delivery went okay overall (12/2/18)- plane landed with a throttle linkage issue and a generator bolt issue (still awaiting the details and the BILL for that - anyway...).  Do to some other delays, weather, paperwork etc - I have not been able to fly the plane, not once.  The plane was towed to the repair hanger to fix the throttle and generator bolt issue.  And so now - 3 weeks after delivery - I believe the tanks are leaking - the plane was topped off in prep for a flight on 12/16 - flight was a no go - returned to plane on 12/22 and tank was 2-3" low.  No obvious blue streaks, no big puddle on the ground etc.

The seller of the plane has been wonderful so far.  The tanks were patched on 10/16/18 - this is ~ the 3rd+ patch on the tanks.  The previous delivery of the plane was delayed in fact so the seller could patch them (my previous post) at his cost.  (Find not necessarily repair)

Net net - my question is this - HOW do I determine if they are truly leaking - and where from - and is this something your average A&P can do?

The seller and I (again, a really good man) are in a bit of a he-said she-said deal.  I will not fly the plane or accept it until right, he feels he delivered a plane that was OK - but who knows - a slow leak could have been present during the entire delivery, yes?  I feel we should split - 70/30, 60/40, etc the cost of a full strip and reseal.  OR - he can just take the plane back - I'm in NC - he is in UT and says this is not an option - at all.

So - power of the FORUM - please respond - how do I track down this gremlin of an issue and how do we make this right?

THANK you all - so so - much... I really want to fly the plane!

Joe K.

as noted above, that much fuel, if it was truly a leak, MUST come out somewhere.  The top and bottom surfaces of the tank are visible and obvious.  There are inspection plates that you can open to smell and look into the spaces aft and outboard of the tank.  The small space forwards of the tank does not have inspection plates but has 3/16" or 1/4" holes under the leading edge to allow for drainage that you could smell fuel through or see obvious leakage.  That forward space also is open to the cabin, so you may smell fuel there if there is leakage IIRC.  The inboard area includes the plate the fuel lines and senders are mounted in, which appears to be a common place for leakage as well.  That will also obviously result in visible fuel if the interior kickpanel (or whatever it's called) is removed, as well as fuel smell.

It's hard to imagine leaking that much fuel without visible or smellable fuel in one of those areas.

[joekinnc]

MANY thanks to all - def leak - was too much of a rookie to look in the right places, once I did... lots of blue...  THANK YOU!!

 

[skydvrboy]

Glad you found out for sure, too bad it was a leak and not just fuel settling.  I doubt you would have any recourse with the seller, but you may with whoever patched the tanks back in October as part of the sale.  I'd start by seeing if they'll stand behind their work.  Good luck!

[mike_elliott]

33 minutes ago, skydvrboy said:

Glad you found out for sure, too bad it was a leak and not just fuel settling.  I doubt you would have any recourse with the seller, but you may with whoever patched the tanks back in October as part of the sale.  I'd start by seeing if they'll stand behind their work.  Good luck!

When you have a leak patched, you wont get a guarantee that a new leak wont spring up elsewhere. Most likely, it will as a leak is an indication of the condition of the sealant. To patch the leak is only a bandaid to deteriorating sealant. To hold someone who put a bandaid on aging sealant to be responsible for new leaks is not practical. If the leak by some small chance is in the exact same spot, you probably dont want him/her repatching it anyway as they probably dont know what they are doing or it is too far gone.

When were the tanks last fully resealed? If never, I suspect 41 year old sealant (and 41 year old sealant technology) has given its best service to this airframe already and should be completely redone by a pro like Paul Beck. You could also up for the more expensive bladder solution which should also last for 40 years, but it is too early to tell with bladders, they havent been out that long in Mooney installations. If they have been resealed within the last 7 years, most of the pro resealers will have a warranty that will help. 

A PPI should have noted sealant condition and age for your consideration prior to acceptance, it is one of the critical Mooney PPI items.

[steingar]

If the aircraft leaks that much gas either something is going to turn blue or there is going to be the mother of all avgas smells.  Someone would have noticed one or the other.  Sounds like an imaginary problem, sorry.

[skydvrboy]

@mike_elliott  Totally agree with you.  No guarantee that a leak wouldn't start somewhere else.  It's a long shot, but the patch leaking where it was sealed would be the only possibility with any recourse.  Whether or not you want the guy fixing the leak who couldn't fix it last time (either through poor existing sealant or incompetence) is a whole different question, IMO.

I'm kind of in the same boat as the OP.  My tanks are weeping.  My AI says it's not yet an airworthiness item, but with full tanks, the smell when opening the hangar or door is pretty strong.  Much less to non-existent when the tanks are lower.  I recall seeing a tank seal entry in my logbooks, but I'll have to check to see if it was a patch job or a complete reseal and by whom.

Edited December 27, 2018 by skydvrboy

[Yetti]

My agreement with the IA is that it is air worthy till it crosses his hangar door.    If someone were to fly the plane and do a hard landing, then more sealant could have been knocked loose.  Fix it and fly it or just don't fill the tanks as full.

[Guest]

From the maintenance manual. Leak not exposed to airflow require repair prior to flight. So leaks in th cabin or enclosed portions of the wing.

Clarence

[nels]

On 12/27/2018 at 3:21 PM, steingar said:

If the aircraft leaks that much gas either something is going to turn blue or there is going to be the mother of all avgas smells.  Someone would have noticed one or the other.  Sounds like an imaginary problem, sorry.

I agree. That much fuel couldn’t have been hiding under a panel and neve found its way to the ground. I bet the stains you saw under a panel were there prior to the patch. Don’t be too hasty. You may have a hell of a nice plane even of it needs one more minor touch up to a prior patch job. Or maybe it isn’t even leaking. Fill it again and recheck.