G100UL - fuel leak

[gabez]

Hello, 

 

I just switched to G100UL and developed a leak within one week and about 80 gallons. see Pics. my mechanic is going to open up the tanks and see what's going on. has anybody had experience yet? perhaps the G100UL is harder on the seal. 

 

Gabe 

 

[Fly Boomer]

3 minutes ago, gabez said:

I just switched to G100UL and developed a leak within one week and about 80 gallons. see Pics. my mechanic is going to open up the tanks and see what's going on. has anybody had experience yet? perhaps the G100UL is harder on the seal. 

In my experience, when fuel stains are brown like that, it's 100LL that has been there for months or years.

[gabez]

I fly every week fuel doesn't really sit there for more than a few days

[Fritz1]

The wrinkled peeling paint looks different from any fuel leak that I have seen, the million $ question is whether the G100UL actually ate the sealant or whether there was a leak before and the G100UL unlike the 100LL just eats the paint now, either way this is highly interesting

[GeeBee]

When was the last reseal?

 

[Ibra]

I know this sounds silly to ask but given it’s “one week effet”, did you put G100UL in both fuel tanks? can you revert to 100LL in one fuel tank? the effet on paint does not look great, even scary !
 

Is that the original tank seal and wing paint?

Edited December 9, 2024 by Ibra

[redbaron1982]

I know many will have a lot to say, but it sounds fishy that after so many years of testing, one person has all this damage in just one week.

[MikeOH]

OPINION:  The OP's pictures strongly suggest tanks that have been weeping/seeping for some time.  If they are now LEAKING after only 80 gallons of G100UL it could be indicative of a more aggressive solvent action or just coincidence.  Hard to tell with a sample size of ONE aircraft!

I am not sure how many GA piston aircraft have wet wing (sealed) tanks but we should start to see more examples like this if G100UL does aggravate leaks.

[gabez]

58 minutes ago, redbaron1982 said:

I know many will have a lot to say, but it sounds fishy that after so many years of testing, one person has all this damage in just one week.

 

9 minutes ago, MikeOH said:

OPINION:  The OP's pictures strongly suggest tanks that have been weeping/seeping for some time.  If they are now LEAKING after only 80 gallons of G100UL it could be indicative of a more aggressive solvent action or just coincidence.  Hard to tell with a sample size of ONE aircraft!

I am not sure how many GA piston aircraft have wet wing (sealed) tanks but we should start to see more examples like this if G100UL does aggravate leaks.

my tanks have not been leaking or sipping just to be clear. the paint job is not great yes, but I did not have this problem. I would have seen blue stain .... obviously. 

The team at Gami has been notified and they are cooperating with the AP/IA that is checking the tanks.

 

As far as testing, if everything was found during testing there wouldn't be ADs, or bugs, or recalls so I am not surprised if problems show up in the real world. 

I will continue to update this thread as things unfold 

[Slick Nick]

Wow that’s some pretty intense damage after such a short time! 

[IvanP]

So let's say, hypothetically, that G100UL does, in fact, eat through Mooney tank sealant in one week or even a month or so. What action do you see more likely to take place:

1. G100UL will not be deemed a "safe" replacement for 100LL and more research and development will have to be done before it will become the only fuel availabe for piston fleet, or 

2. G100UL will be crammed down our throats to appease the environuts and the FAA will issue an AD requiring either full strip and reseal of ALL Mooney tanks with some magical sealant that can withstand the new fuel or bladders. Of course, we do not know the price, availability, or longevity of this magic potion yet. 

Given the current price of full strip and reseal, option 2 would be really scary. The last time I inquired, it was close to $30k for full strip and reseal on a long body with Monroy extended range tanks and the good shops doing this tend to be booked far in advance. Such AD could potentially ground most of Mooney fleet for quite some time.  Making this procedure mandatory would probably drive the price even higher. Sort of like the AD on V-band turbo clamps that came out last year. Before the AD, the clamps were pricey already (around $500 by my recollection), but after the AD the list price shot up to almost $3k and they seem to be made of unobtainium. 

Edited December 10, 2024 by IvanP

[Ibra]

4 hours ago, IvanP said:

Given the current price of full strip and reseal, option 2 would be really scary. The last time I inquired, it was close to $30k for full strip and reseal on a long body with Monroy extended range tanks and the good shops doing this tend to be booked far in advance. Such AD could potentially ground most of Mooney fleet for quite some time.  Making this procedure mandatory would probably drive the price even higher. Sort of like the AD on V-band turbo clamps that came out last year.

I wouldn't worry about AD as there are already thousands of Mooneys already flying on G100UL for the last 2 months or so with no problems, we will see in 5 years or so? 

The issue is that if a Mooney already has big leak that was acceptable with 100LL, it's likely to be aggravated, especially, the paint will take a hit with G100UL !

On effect on paint, we already know that the paint will take a hit with G100UL (part of it's specs shall we say) and many owners are happy to have this kind of trade-off while making precautions

Where I am puzzled is that all of this happens after one week, even the occasional spills after reful would be problematic !

Long term, I am sure we will have new sealants and paints compounds that work better with G100UL

Also, there is something weired about chemicals after first use , we should expect things to stablise at some point? reminds me of oil consumption after changing oil brands (or even new oil from same brand)

Edited December 10, 2024 by Ibra

[Fly Boomer]

9 hours ago, gabez said:

if everything was found during testing there wouldn't be ADs, or bugs, or recalls

This is the first I have heard of ADs, bugs, or recalls on the G100UL.  Can you point me to the documentation?

[gabez]

19 minutes ago, Fly Boomer said:

This is the first I have heard of ADs, bugs, or recalls on the G100UL.  Can you point me to the documentation?

that was a general comment back to yours after 10 years of testing. 

[gabez]

2 hours ago, Ibra said:

I wouldn't worry about AD as there are already thousands of Mooneys already flying on G100UL for the last 2 months or so with no problems, we will see in 5 years or so? 

The issue is that if a Mooney already has big leak that was acceptable with 100LL, it's likely to be aggravated, especially, the paint will take a hit with G100UL !

On effect on paint, we already know that the paint will take a hit with G100UL (part of it's specs shall we say) and many owners are happy to have this kind of trade-off while making precautions

Where I am puzzled is that all of this happens after one week, even the occasional spills after reful would be problematic !

Long term, I am sure we will have new sealants and paints compounds that work better with G100UL

Also, there is something weired about chemicals after first use , we should expect things to stablise at some point? reminds me of oil consumption after changing oil brands (or even new oil from same brand)

are there really thousands of Mooneys out there flying on G100? there are ~90s Mooneys on trade a plane, GMAX has 24 and 99 open controller which are probably the same as GMAX and Autotrader. even if there are thousand of Mooneys in the US, stating they are flying on G100 is unreasonable. Are you running G100? Are you going to run it now?

There was and there is no blue stain in my pictures, if that was a current leak there would be blue dye on the paint, which I would have spotted. 

[Pinecone]

There are something like 7000 Mooneys registered.

But unlikely thousands flying on G100UL, as it is only available at two airports in CA.

But it was tested for years in wet wing airplanes.   Possibly in this case there had been patches make with a marginal sealant in the past.

[Fly Boomer]

1 hour ago, gabez said:

that was a general comment back to yours after 10 years of testing. 

Not my comment.

[AJ88V]

Kinda shocked with this.  Never seen paint peel/blister like that from anything other than paint stripper.  The wet-tank sealant is polyurethane, an extremely chemically-resistant material.  But @gabez points out that there is no blue staining on most of those leaks.

(tongue in cheek) Maybe we've just found a cheaper way to strip old tank sealant?

(but seriously) If GL100U can really cause the tanks to leak like that, imagine the dissolved material that would be getting drawn into the fuel system and engine....

[Echo]

Sorry you are experiencing this.  Do you happen to have some "before" photos?  You acknowledge that your paint isn't great (neither is mine).  Just a reference for before and after the UL utilization would be great.  Those "after" photos are very sobering to say the least.  Updates appreciated.  Scott

[haymak3r]

Do you happen to have any pics before you switched? Just for comparison of what we're looking at? There is some serious paint damage there, and it is super hard to believe this came from a fuel.. Does Brake cleaner or Brake fluid eat paint that fast? lol

[haymak3r]

LOL no @Echo. It's that we basically asked the same thing at the same time.. Sorry for the confusion. I was definitely NOT laughing at what you posted as it is totally relevant.

Edited December 10, 2024 by haymak3r

[Ibra]

3 hours ago, gabez said:

are there really thousands of Mooneys out there flying on G100?

Sorry, I was exagerating a bit and also sorry to see this happening to your aircraft, however, here are probably dozens (10 or 100) who already got STC and took gallons of G100UL in the last two months from the few airports delivering it in CA, maybe someone who already did can share their feedback on MooneySpace?

As always, we have one data point is not enough to do stats, so one need to look at the "other set" (survivorship bias)

 

Edited December 10, 2024 by Ibra

[IvanP]

6 hours ago, Ibra said:

I wouldn't worry about AD as there are already thousands of Mooneys already flying on G100UL for the last 2 months or so with no problems, we will see in 5 years or so? 

The issue is that if a Mooney already has big leak that was acceptable with 100LL, it's likely to be aggravated, especially, the paint will take a hit with G100UL !

While there are several thousand  Mooneys currently registered, I doubt that there are "thousands of Mooneys flying G100UL". The fuel is curently distributed at handful of airports so my guess is that there may be less than 100 Mooneys currently using this fuel. The number of STCs sold would be agood indication. 

"Big leak" is not acceptable with any fuel. 

Edited December 10, 2024 by IvanP

[201Mooniac]

Sorry to see you having this issue.  I got the STC when KRHV arranged for the STC for free.  I have no issues at all but it has only been 5 weeks so far so I'm not sure that tells us much..

[Will.iam]

1 hour ago, 201Mooniac said:

Sorry to see you having this issue.  I got the STC when KRHV arranged for the STC for free.  I have no issues at all but it has only been 5 weeks so far so I'm not sure that tells us much..

Well if you have run 80 gallons worth of g100ul that would be a significant data point as in your tanks have not started leaking and if you did have a leak to what extent the paint gets removed/destroyed.