Based on the G100UL fuel leak thread what's your position?

[PT20J]

George addressed paint damage and fuel tank sealant, but what about o-ring swelling? It's one thing to say that all the old Mooneys need tank reseals. It's quite another to say that the whole fleet needs all its o-rings replaced.

[Andy95W]

1 hour ago, PT20J said:

George addressed paint damage and fuel tank sealant, but what about o-ring swelling? It's one thing to say that all the old Mooneys need tank reseals. It's quite another to say that the whole fleet needs all its o-rings replaced.

He somewhat addressed that.  Something along the lines of 100LL causes o-rings to swell also, and it’s the owner’s fault if they have the “wrong” o-rings installed.

[redbaron1982]

1 minute ago, Andy95W said:

He somewhat addressed that.  Something along the lines of 100LL causes o-rings to swell also, and it’s the owner’s fault if they have the “wrong” o-rings installed.

Didn't he go as far as saying that the fuel selector o-ring size defined by the manufacturer is wrong and a smaller one should be used? Like, anything but saying that G100UL has material compatibility issues. 

[varlajo]

26 minutes ago, redbaron1982 said:

Didn't he go as far as saying that the fuel selector o-ring size defined by the manufacturer is wrong and a smaller one should be used? Like, anything but saying that G100UL has material compatibility issues. 

No, I think he only spoke about o-ring material, not size. 

[hazek]

3 hours ago, varlajo said:

No, I think he only spoke about o-ring material, not size. 

In the comments of the Busch interview video Braly says the o rings used in testing by Michael Luvara was at least 1 size too big:

[Paul Thomas]

20 hours ago, George Braly said:

Basically, those repair shops tell us that any Mooney with more than about 20 years since factory sealant is a ticking leak-bomb for fuel leakage. 

George

My airplane is an 84 but the tanks were sealed in 83. No leaks and I don't anticipate they'll leak anytime soon. Here is what I'm willing to do.  You can borescope the tanks and you can give an opinion on whether they'll leak in the next 12 or 24 months. If you say they'll leak, I'll keep burning 100LL and we'll see whether they are the timebomb you claim. My prediction is my tanks will be just fine and I have zero risk with that.

If my tanks/airplane are suitable for G100UL, I'll use G100UL. If I have any issues with tanks, the fuel system, the engine, or paint stripping off (I'm responsible for staining), GAMI/you are 100% responsible for fixing it. I'm still predicting my tanks will be fine, but my confidence level is down, down enough that I'm not willing to take the risk without a warranty.  

Either the product is suitable or it isn't. The only way to find out is more real world testing with real users.

If George is willing to to that, I hope other owners to make the same offer so that we can have a more representative sample.

20 hours ago, George Braly said:

There are about 150 aircraft that have used G100UL Avgas.   Of that number, there are 5 that have reported in-service issues that did not have clear evidence of prior leakage of 100LL. 

George

Another way to word that statistic, is that after inspecting airplanes who had issues with G100UL, no fault could be find that is can be assessed to the aircraft or it's maintenance for 5 of the aircraft inspected. That would be an undisputed 3+% failure rate for unknown reason and one of about 10% for aircraft that have possible pre-existing conditions. It's a scary number to look from an owner perspective when 100LL is still readily available. It will be interesting to see how those numbers change over time.

[N201MKTurbo]

I have done more tank work than I care to think about. I don’t think I could find a leak with a borescope. Most leaks come from air bubbles in the sealant, or the sealant delaminating from the metal. Both would be almost impossible to see. I have seen sealant that is failing and turning to crumbs. You might be able to see that with a borescope. I don’t know what causes that, but I don’t think it is time. I think it is defective sealant from the start, or attack by some chemical. I have seen very old sealant that had no signs of deterioration.  Most leaks I have fixed were in good looking sealant. I think poor surface preparation before applying the sealant causes way more leaks than sealant failure.

[haymak3r]

23 hours ago, GeeBee said:

Yes, I did watch it. George Braly said basically Mooneys and twin Cessnas with integral tanks are leaking fuel storage devices. He said, they have always leaked and will continue to leak no matter the fuel. He said they leak with 100LL at the same rate as with G100UL.

Outside of the occasional drip running off and on to the paint from my sump valves, I have no leaks. on my J. Does that mean I should feel confident that g100UL won't mess my paint, or sealant up? Unfortunately, I can't be.. Not with the evidence I've seen so far.

[haymak3r]

23 hours ago, George Braly said:

There are several Mooneys that have used G100UL Avgas.   No leaks and no paint damage.  

I borescoped the fuel tank of one Mooney that had leaked.  There were at least two (likely three) different types of internal sealant applications (wrong sealant - wrong technique) clearly visible where someone had tried to do field repairs of earlier 100LL leakage.   There are three shops around the country that specialize in stripping the interior fuel tank sealant and then applying new sealant - - - properly applying new sealant.  (Note the factory applied sealant was never properly applied by the factory - - according to the repair shops.)

Basically, those repair shops tell us that any Mooney with more than about 20 years since factory sealant is a ticking leak-bomb for fuel leakage. 

I inspected a Mooney at RHV that had been using G100UL Avgas for several months.  No evidence of any issues.  I asked the owner if I could borescope his fuel tanks.  He grinned and approved.   When I looked in the tank the sealant was as pristine and perfect as you could ever expect.   

When I quizzed the owner, he grinned and told me that his plane started leaking 100LL when it was about 15 years old.  He had it resealed about 8 years previous - - at  "Weep No More"  (shop in Minnesota that specializes in resealing fuel tanks.) 

                                         ***********

There are about 150 aircraft that have used G100UL Avgas.   Of that number, there are 5 that have reported in-service issues that did not have clear evidence of prior leakage of 100LL.   

If you spill G100UL on your wing during refueling - - and clean it up  ("Good fuel hygiene") before it evaporates and dries out in sunlight) then it does no damage to the paint.   If you spill it and let it sit and evaporate for a while, without cleaning it up, then it will slightly stain the paint a brownish color. 

Various ones of the popular crystal coatings offer substantial protection of the paint.

A couple of those commercial products are extremely effective at protecting the paint from stains and damage and have a number of other general benefits with respect to improving the durability of the paint and greatly enhancing the ability to clean  bugs and debris from the wings. 

George

Hi George, 

Thank you for posting here. I am sure like myself, others appreciate it. Unfortunately, I cannot in good conscience allow myself to use a fuel that has the potential to do harm to my aircraft. I understand there is "good fuel hygiene", but as I am sure you know, there are times where all the normal resources you may need to properly clean up a mess are not readily available. Even just fueling up the plane, I can see a little splash back coming back out of the fuel neck. This to me is a cause for concern. The occasional drop from simply sumping the tanks, Or, as I've seen on my own aircraft, a screw from one of the tank inspection plates needs to be resealed.. All of this having a potential to cost a LOT of time, and money repairing seems like a 'no deal' situation. Simply re-sealing our tanks should not be the go to solution to this either. Going to weep no more means a potential for more than a year wait. That's not acceptable either. I had high hopes when following along with your research and approval process for g100ul. It is very discouraging that we are now here, and have little choice but to allow our paint, or sealant suffer because there isn't a great alternative available to us for 100LL. 

If the evidence that has been brought forward within the community is blown out of proportion, then I get it. Let's not dwell on a non issue.. But, at the same time, I don't think this should be dismissed as, "it's just time to reseal those tanks".  

Like all good studies, the larger the pool of data, the better. 150 aircraft is, in my opinion, not a very good representation of GA as a whole. Like others have said, a 3% failure rate is completely unacceptable. Even in the industry I work in. A 3% failure rate in aircraft? I think should potentially be fleet grounding..

-Chris

[GeeBee]

42 minutes ago, haymak3r said:

Like others have said, a 3% failure rate is completely unacceptable. Even in the industry I work in. A 3% failure rate in aircraft? I think should potentially be fleet grounding..

A 3% failure rate in a fleet that is how old? 45+ years average? I think expecting better with a 45 year old fleet is not possible.

[George Braly]

Like all good studies, the larger the pool of data, the better. 150 aircraft is, in my opinion, not a very good representation of GA as a whole. Like others have said, a 3% failure rate is completely unacceptable. Even in the industry I work in. A 3% failure rate in aircraft? I think should potentially be fleet grounding.

The only issues for which the FAA will  "ground" an aircraft is for some type of demonstrative  "Safety of Flight" issue.

None of the reported in-service difficulties have involved any type of "safety of flight" issue.   The FAA has maintained a spreadsheet on each of these and agrees that there is no safety of flight issue. 

As for the occasional "splashed" droplet on the paint - -  there are a couple of routine and easy ways to deal with that. 

Any kind of routine "shop rag" in hour hip pocket or  even a paper towel in your baggage compartment will clean that up and now result in any visible change to the paint. 

In addition, we have handed out refueling mats with the STCs, beginning at RHV.    These are grey absorbent mats with a 3" hole in the middle.   You can keep a half-dozen of them in the baggage compartment.  They can be reused multiple times. 

If you use those, then they also protect the paint surface from being scratched or damaged by the refueler allowing the refueling nozzle to to rest on the surface of the wing (which we have observed from time to time.)   

As also mentioned, some of the crystal / graphene coatings are very effective at protecting the paint. 

 With respect to sump drains,  there really should not be any splashing or droplet from those, but again, it takes no more than about 10 seconds to wipe the area around the filler port with a red shop rag when you finish with the sump drain. 

In our experience - - so far,   - - if your tanks are not leaking 100LL, then using G100UL avgas does not cause them to initiate leakage.  

George

[hazek]

26 minutes ago, GeeBee said:

A 3% failure rate in a fleet that is how old? 45+ years average? I think expecting better with a 45 year old fleet is not possible.

People are repeating this number now. But we have no details regarding those 150 aircraft that have used G100UL. Are all of them exclusive G100UL users? How many just tried to use the fuel once, mixed with 100LL at that! How many refueled it and left it sit in their tank for an extended period of time. We have no details and Braly said in the comments of the video that use is of varying degrees without specifics:

So that 3% is meaningless as it could be far far greater % when only regular or exclusive users are considered.

[George Braly]

53 minutes ago, haymak3r said:

Hi George, 

Like all good studies, the larger the pool of data, the better. 150 aircraft is, in my opinion, not a very good representation of GA as a whole. Like others have said, a 3% failure rate is completely unacceptable. Even in the industry I work in. A 3% failure rate in aircraft? I think should potentially be fleet grounding..

-Chris

Chris,  

A lot of people not involved in actual FAA aircraft and engine certification work may not appreciate the "science" of  when "good enough" is "good enough". 

Lycoming and Continental can certify a brand new - - "clean sheet" engine design and get it certified by doing a single 150 hour engine test - - following a defined / prescribed  "protocol".  

Then they can produce them and sell them as fast as they can make them, if they have customers.  

One engine.  150 hours.  

In engineering, we should normally be looking for "boundary conditions".   If you,  "worst case" conditions or applications. 

For example,  GAMI,  unlike the PAFI program,  was able to work with the FAA to identify a "worst case"  (i.e., boundary condition) engine and associated operating conditions, so that a then "robust"  detonation test matrix, executed on that "worst case"  (boundary condition) engine would establish that all of the remaining engines, operating under design and operating envelope conditions which are then known to be  "less severe"  than the "test day" engine & operating conditions - - would be assured of being able to operate on G100UL Avgas free of detonation.  

Otherwise, if you approach the problem in any other manner,  you end up with a constant chorus of  "... Yeah!  But - - but - - but whattabout my IO-550 with 9:1 CR"  or . . .  "... whatabbout our R-2800 on our CAF A26 or our CW-3350 on FIFI ?" 

The same applies to "hot day / hot fuel"  climb cooling / vapor lock testing. 

On September 5th, 2012, we completed that testing under direct supervision / participation of four senior FAA propulsion engineers who were on site at GAMI.  By requirement - - it was a real 100+F OAT day.  (105F to be exact).   At Ada, that translates into a 110 degree day at S.L.    With fuel that was custom produced to be very near the maximum permissible Reid Vapor Pressure.    AND to do that "back to back"  same-day - -  using 100LL that was also custom blended to be near the upper end of the RVP range permitted in the specification.   AND,  to do that on a turbocharged engine at various altitudes up to and including 25,000 feet.   With fuel temperature sensors scattered around to record the temperature of the two fuels in the fuel tanks and at the firewall and coming out of the gascolator going into the fuel pump.  

It is that type of approach, using a "boundary condition" philosophy for the testing that allows any progress to be made in the general aviation aircraft world. 

Yes,  some things are statistical - -  fatigue cracks are an example.   When we did the repair on the wing structure of the fleet of T-34s - -  that was a requirement for portions.   Example, we developed a new high strength wing bolt using a well proven state of the art metallurgy.   Lots of fatigue/damage tolerant engineers would look at the specification for that material and simply "nod their heads" that was good enough.   However, we took multiple samples of the new bolts and the old bolts to the test lab.  All of the old bolts broke between 75 and 79,000 lbs of tensile load.   All of the new bolt design broke between 94 and 97,000 lbs.  That is an example of the application of testing multiple articles - - when it is appropriate. 

So, in our judgment, and that of the FAA, the approach we used for the certification of G100UL was appropriate. 

I think one of our failings was in our lack of robust understanding or appreciation of the issues involved with our rapidly aging fleet of aircraft.  (Example, the Mooney fatal crash in Australia, two years ago, due to a 29 year old nitrile O-ring that failed in 100LL and caused a fuel leak in the engine compartment.   - - - if that aircraft had been using G100UL avgas then the fuel would have been blamed for that tragedy.)

One other thought:  There is no perfect fuel.  Not 100LL.   Not G100UL avgas.  

 Your questions and concerns are always welcome.

George

 

   

 

 

[EricJ]

The more they talk, the worse it gets.

 

[varlajo]

3 hours ago, George Braly said:

One other thought:  There is no perfect fuel.  Not 100LL.   Not G100UL avgas.  

Exactly. In today's regulatory environment, 100LL and G100UL can coexist and compete - except in Santa Clara County, where political circumstances created a G100UL monopoly in the market that cannot accept UL94. Elsewhere, we as consumers vote with our wallets for the "imperfect" fuel of our liking. The case of KWVI, where both 100LL and G100UL are available, clearly shows what that vote is.

I think it is abundantly clear that a considerable cohort of pilots do not want your product. Our decisions are based on independent data, be it scientific or empirical, and have nothing to do with lead or no lead; it is clear as day that leaded avgas is going away. We just do not want this fuel in our planes. 

[redbaron1982]

23 minutes ago, varlajo said:

Elsewhere, we as consumers vote with our wallets for the "imperfect" fuel of our liking.

It is important to remember that good old George was advocating for banning 100LL state wide in California. 

Such a nice guy and advocate of General Aviation he is. 

 

[hammdo]

Just curious:

If that is true, where is that documented? I don’t recall seeing anything with a direct quote. Not saying one way or the other, just want to see where that was stated…

-Don

[redbaron1982]

23 minutes ago, hammdo said:

Just curious:

If that is true, where is that documented? I don’t recall seeing anything with a direct quote. Not saying one way or the other, just want to see where that was stated…

-Don

This is George Braly declation, defending the motion to ban 100LL in California. https://drive.google.com/file/d/14JkPLQIAVY-hA24TZQWy0i3UhMost47B/view

DECLARATION OF GEORGE W.BRALY IN SUPPORT OF PLAINTIFF CENTER FOR ENVIRONMENTAL HEALTH’S REPLY TO  SETTLING DEFENDANTS’ OPPOSITION TO MOTION TO ENFORCE CONSENT JUDGMENT AND MOTION TO MODIFY CONSENT JUDGMENT

Which includes a passage specific about the defective Mooney design (quote from Mr Braly declaration):

"Mooney aircraft have a unique and inadequate type of fuel tank construction, as compared to the standards for the certified aircraft industry."

 

Edited January 22 by redbaron1982

[GeeBee]

20 minutes ago, redbaron1982 said:

It is important to remember that good old George was advocating for banning 100LL state wide in California. 

Such a nice guy and advocate of General Aviation he is. 

 

So is everyone who knows anything about what is killing our engines. There is a reason why lead is a top line metal in your oil analysis. It is the greatest predictor of future engine problems. All that "sludge" in you crank shaft hollow? Lead. All that crap on your valves and plugs? Lead. Common. reason for sticking valves? Lead. 

I can't wait to get rid of lead in my engine.

[gabez]

as the last data I pulled back in august KWVI was selling 2-400 gallons per month of G100UL so all these planes flying around using G100UL is BS. 

Obviously GAMI has yet to hire a competent PR/Marketing person to help them

[gabez]

6 hours ago, hazek said:

People are repeating this number now. But we have no details regarding those 150 aircraft that have used G100UL. Are all of them exclusive G100UL users? How many just tried to use the fuel once, mixed with 100LL at that! How many refueled it and left it sit in their tank for an extended period of time. We have no details and Braly said in the comments of the video that use is of varying degrees without specifics:

So that 3% is meaningless as it could be far far greater % when only regular or exclusive users are considered.

there is a 100+ pages on beech talk were we all asked these questions to GAMI with deferred answered. you can spend days reading it and I think you could enjoy it

[haymak3r]

22 hours ago, George Braly said:

Chris,  

A lot of people not involved in actual FAA aircraft and engine certification work may not appreciate the "science" of  when "good enough" is "good enough". 

Lycoming and Continental can certify a brand new - - "clean sheet" engine design and get it certified by doing a single 150 hour engine test - - following a defined / prescribed  "protocol".  

Then they can produce them and sell them as fast as they can make them, if they have customers.  

One engine.  150 hours.  

In engineering, we should normally be looking for "boundary conditions".   If you,  "worst case" conditions or applications. 

For example,  GAMI,  unlike the PAFI program,  was able to work with the FAA to identify a "worst case"  (i.e., boundary condition) engine and associated operating conditions, so that a then "robust"  detonation test matrix, executed on that "worst case"  (boundary condition) engine would establish that all of the remaining engines, operating under design and operating envelope conditions which are then known to be  "less severe"  than the "test day" engine & operating conditions - - would be assured of being able to operate on G100UL Avgas free of detonation.  

Otherwise, if you approach the problem in any other manner,  you end up with a constant chorus of  "... Yeah!  But - - but - - but whattabout my IO-550 with 9:1 CR"  or . . .  "... whatabbout our R-2800 on our CAF A26 or our CW-3350 on FIFI ?" 

The same applies to "hot day / hot fuel"  climb cooling / vapor lock testing. 

On September 5th, 2012, we completed that testing under direct supervision / participation of four senior FAA propulsion engineers who were on site at GAMI.  By requirement - - it was a real 100+F OAT day.  (105F to be exact).   At Ada, that translates into a 110 degree day at S.L.    With fuel that was custom produced to be very near the maximum permissible Reid Vapor Pressure.    AND to do that "back to back"  same-day - -  using 100LL that was also custom blended to be near the upper end of the RVP range permitted in the specification.   AND,  to do that on a turbocharged engine at various altitudes up to and including 25,000 feet.   With fuel temperature sensors scattered around to record the temperature of the two fuels in the fuel tanks and at the firewall and coming out of the gascolator going into the fuel pump.  

It is that type of approach, using a "boundary condition" philosophy for the testing that allows any progress to be made in the general aviation aircraft world. 

Yes,  some things are statistical - -  fatigue cracks are an example.   When we did the repair on the wing structure of the fleet of T-34s - -  that was a requirement for portions.   Example, we developed a new high strength wing bolt using a well proven state of the art metallurgy.   Lots of fatigue/damage tolerant engineers would look at the specification for that material and simply "nod their heads" that was good enough.   However, we took multiple samples of the new bolts and the old bolts to the test lab.  All of the old bolts broke between 75 and 79,000 lbs of tensile load.   All of the new bolt design broke between 94 and 97,000 lbs.  That is an example of the application of testing multiple articles - - when it is appropriate. 

So, in our judgment, and that of the FAA, the approach we used for the certification of G100UL was appropriate. 

I think one of our failings was in our lack of robust understanding or appreciation of the issues involved with our rapidly aging fleet of aircraft.  (Example, the Mooney fatal crash in Australia, two years ago, due to a 29 year old nitrile O-ring that failed in 100LL and caused a fuel leak in the engine compartment.   - - - if that aircraft had been using G100UL avgas then the fuel would have been blamed for that tragedy.)

One other thought:  There is no perfect fuel.  Not 100LL.   Not G100UL avgas.  

 Your questions and concerns are always welcome.

George

 

   

 

 

I definitely understand your testing philosophy, and the sophistication required to accomplish the testing parameters required by engine manufacturers/faa. I don't think this is the issue though. I applaud your effort in creating a suitable alternative to 100LL. I don't fear for engine issues if I were to use G100UL. Unfortunately, there is a but.. I also understand the impossible task of testing your fuel on all the different aircraft types out there. As an aircraft owner though, I am responsible for the entire aircraft, not just the engine. I don't know about you, but I cannot afford to be repairing the paint on my aircraft every few years because the fuel I have to use was replaced with G100UL. I also don't see any warranties regarding any repairs to the paint or other items along the fuel system. 

 

All I am asking for is an acknowledgement that you are aware of and have seen the evidence that your fuel is ruining paint if it gets on it. It would be nice to also know that you are looking in to these reports, and seeing if there is anything that can be done to remedy this. We do not have much time left before we are forced out of 100LL.. 2030 will be here before we know it.

 

I hope that us mooney owners, and other aircraft with wet tanks are not just seen as outside the "boundary condition". And that we just have to deal with the risks once 100LL is no longer available.

 

-Chris

 

[haymak3r]

18 hours ago, GeeBee said:

So is everyone who knows anything about what is killing our engines. There is a reason why lead is a top line metal in your oil analysis. It is the greatest predictor of future engine problems. All that "sludge" in you crank shaft hollow? Lead. All that crap on your valves and plugs? Lead. Common. reason for sticking valves? Lead. 

I can't wait to get rid of lead in my engine.

Exactly. Right there with you!

[redbaron1982]

5 minutes ago, haymak3r said:

All I am asking for is an acknowledgement that you are aware of and have seen the evidence that your fuel is ruining paint if it gets on it. It would be nice to also know that you are looking in to these reports, and seeing if there is anything that can be done to remedy this.

I think George already stated that if your tank leak is because your aircraft has an inferior design or was not maintained correctly.

Also, if you have any issue with your fuel system is because you have neglected your airplane for many many years.

Finally, if your paint gets damaged it's because you don't exercise standard refueling hygiene.

Any issue that you have in your airplane after you start using G100UL is due to correlation, not causation. Fancy words to say: it was just coincidence that your tanks started leaking after you switched to G100UL, it would have happened exactly the same if you would've continue with 100LL.

I'm not saying that I agree with Mr Braly, I'm just summarizing what he has repeated everywhere, in some cases, as a expert witness in the CEH California trial.

[Mark89114]

I know no more or have more confidence in this whole debacle than I did 58 pages ago.

And that is the problem.