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

[redbaron1982]

No, I meant on the ruling regarding the 100LL ban.

[gabez]

13 hours ago, IvanP said:

does not look like the fuel is in high demand. Less than 200 gal sold in March. That is like 3-4 planes fueling up in last 21 days. Flightaware shows more than 40 arrivals today alone. 

they only sent me march through the 11th I tried to note it on the chart but it's not super obvious. But yes I would say there are only single digit planes using it. 

I was talking to Terry yesterday at united, as one of my P-leads is acting out, and he was telling me he had a C140 came in with a rough running engine on G1, the primer was stuck and wouldn't close properly. the owner thought it was closed but it wasn't. That matches with Mike's finding on the primer o-rings. 

I think the tanks on the 140 are metal but not sure, perhaps that's why he didn't see any issues until the fuel attacked the o-rings 

[gabez]

11 minutes ago, redbaron1982 said:

No, I meant on the ruling regarding the 100LL ban.

oh sorry. besides what's public I don't know much more. 

[toto]

11 minutes ago, gabez said:

they only sent me march through the 11th I tried to note it on the chart but it's not super obvious. But yes I would say there are only single digit planes using it. 

I was talking to Terry yesterday at united, as one of my P-leads is acting out, and he was telling me he had a C140 came in with a rough running engine on G1, the primer was stuck and wouldn't close properly. the owner thought it was closed but it wasn't. That matches with Mike's finding on the primer o-rings. 

I think the tanks on the 140 are metal but not sure, perhaps that's why he didn't see any issues until the fuel attacked the o-rings 

@A64Pilot might have input on the C140

[A64Pilot]

2 hours ago, gabez said:

they only sent me march through the 11th I tried to note it on the chart but it's not super obvious. But yes I would say there are only single digit planes using it. 

I was talking to Terry yesterday at united, as one of my P-leads is acting out, and he was telling me he had a C140 came in with a rough running engine on G1, the primer was stuck and wouldn't close properly. the owner thought it was closed but it wasn't. That matches with Mike's finding on the primer o-rings. 

I think the tanks on the 140 are metal but not sure, perhaps that's why he didn't see any issues until the fuel attacked the o-rings 

They are metal tanks held into the wing by metal straps, very much like an old car. The fuel lines to the strainer are steel, I don’t think there is any rubber in the fuel selector, but there may be one under the cap where the lever is attached. The original carb float was brass and the original needle and seat are steel, but I think modern floats are plastic of some kind and some needles have neoprene tips as the original steel on steel could leak slowly.

Primers can be a source of engine failure / low power as if not closed they can make an engine run stupid rich. Normally the O-ring wears and I think the primer leaks slightly when used. Real easy to change but can be a significant airworthiness issue.

[mluvara]

1 hour ago, A64Pilot said:

They are metal tanks held into the wing by metal straps, very much like an old car. The fuel lines to the strainer are steel, I don’t think there is any rubber in the fuel selector, but there may be one under the cap where the lever is attached. The original carb float was brass and the original needle and seat are steel, but I think modern floats are plastic of some kind and some needles have neoprene tips as the original steel on steel could leak slowly.

Primers can be a source of engine failure / low power as if not closed they can make an engine run stupid rich. Normally the O-ring wears and I think the primer leaks slightly when used. Real easy to change but can be a significant airworthiness issue.

FAA issued this notice last week seeking primer failure reports, which is of a related situation. 

“The FAA is investigating a report of a worn fuel primer pump that may be installed in general aviation aircraft following a non-fatal accident on a Champion 7EC Traveler. During the initial takeoff climb, the pilot noticed a significant decrease in the engine rpm and lost full engine power shortly after. It was determined that the fuel primer pump in the accident was worn and unable to lock properly causing an overly rich fuel mixture. The airplane sustained substantial damage to the right wing and the fuselage.”

https://www.faasafety.gov/SPANS/noticeView.aspx?nid=14328

FAA_ACS_-_7EC_Fuel_Primer_Pump.pdf

Edited March 22 by mluvara

[Aaviationist]

This is tiresome. 
 

how’s getting gami to pay for your tank patch working out?

[gabez]

15 minutes ago, Aaviationist said:

This is tiresome. 
 

how’s getting gami to pay for your tank patch working out?

crickets.....

[IvanP]

4 hours ago, mluvara said:

FAA issued this notice last week seeking primer failure reports, which is of a related situation. 

“The FAA is investigating a report of a worn fuel primer pump that may be installed in general aviation aircraft following a non-fatal accident on a Champion 7EC Traveler. During the initial takeoff climb, the pilot noticed a significant decrease in the engine rpm and lost full engine power shortly after. It was determined that the fuel primer pump in the accident was worn and unable to lock properly causing an overly rich fuel mixture. The airplane sustained substantial damage to the right wing and the fuselage.”

https://www.faasafety.gov/SPANS/noticeView.aspx?nid=14328

FAA_ACS_-_7EC_Fuel_Primer_Pump.pdf 367.76 kB · 5 downloads

This notice is related to the locking mechanism of the primer pump which appears to have caused the problem in the aircraft in question. However, I can see that damaged o-ring could produce similar result. I would guess that most of these pumps currently in use have o-rings manufactured from materials that GAMI deems "substandard" with respect to resistance to G100UL.

[mluvara]

9 minutes ago, IvanP said:

This notice is related to the locking mechanism of the primer pump which appears to have caused the problem in the aircraft in question. However, I can see that damaged o-ring could produce similar result. I would guess that most of these pumps currently in use have o-rings manufactured from materials that GAMI deems "substandard" with respect to resistance to G100UL.

Yes. Agree. I was trying to relate the point of a non fully seated primer (whether lock pin, o ring/debris, etc) causing the effect.

[A64Pilot]

1 hour ago, IvanP said:

This notice is related to the locking mechanism of the primer pump which appears to have caused the problem in the aircraft in question. However, I can see that damaged o-ring could produce similar result. I would guess that most of these pumps currently in use have o-rings manufactured from materials that GAMI deems "substandard" with respect to resistance to G100UL.

They do as of course Viton didn’t exist back then.

Almost certainly due to its resistence to wear Cessna I believe recommended the switch to Viton in primers some time ago, not sure how long ago

Viton is tougher, has I believe a higher durometer. Years ago when I was cave diving I switched to Viton on all my tanks because it’s an unlikely but possible point of failure. I don’t believe Viton is a direct replacement for Buna-N in all uses as it’s tougher to compress, at least the Viton I’ve used is.

Anyway it’s one thing for Gami to recommend it, but a completely different thing for average guy to know this, and a third thing for them to understand the importance.

Average person is sure it’s safe or the FAA wouldn’t have approved it, right?

Edited March 23 by A64Pilot

[A64Pilot]

1 hour ago, mluvara said:

Yes. Agree. I was trying to relate the point of a non fully seated primer (whether lock pin, o ring/debris, etc) causing the effect.

I believe a primer has two check valves, one opens when you pull it back and allows it to fill with fuel, then as you push the primer it closers and the other opens allowing fuel to go to the engine, the way they are they both will open and allow fuel to be sucked through the primer by gravity or engine vacuum. I think when the primer is closed it blocks these valve openings so fuel can’t flow.

I think maybe on the 140 in question a swelled O-ring was keeping the primer from fully closing, maybe. Just a guess actually but I can see it happening, and we know the Gami fuel swells Buna-N O rings.

[mluvara]

23 hours ago, redbaron1982 said:

No, I meant on the ruling regarding the 100LL ban.

From what I can tell, the judge has not issued a final ruling yet.

It appears that the CEH sent a survey out about G100UL interest at FBO's after the Mar 5 hearing in order to show 'demand' for G100UL. A request was submitted on Mar 18th (11th hour?) to add it as new evidence (Ex Parte).

CEH

1. Ex Parte Application
2. Declaration

Settling Defendants Response

1. Opposition
2. Declaration

Excerpts attached

CEH:

 

 

 

 

 

Settling Defendants:

 

Edited March 23 by mluvara

[Marc_B]

I find it interesting that an email of “interest” is suggested to speak more than the fact that only 2 FBOs in California carry G100UL with decreasing demand in the sales of 200-300 gal/month.

I suspect the judge should see through this as well.  “Interest” doesn’t equal demand.

[gabez]

3 hours ago, Marc_B said:

I find it interesting that an email of “interest” is suggested to speak more than the fact that only 2 FBOs in California carry G100UL with decreasing demand in the sales of 200-300 gal/month.

I suspect the judge should see through this as well. 

I'd say so, let's see how many gallons Tupelo sells next weekend. 

[MikeOH]

4 hours ago, Marc_B said:

I find it interesting that an email of “interest” is suggested to speak more than the fact that only 2 FBOs in California carry G100UL with decreasing demand in the sales of 200-300 gal/month.

I suspect the judge should see through this as well.  “Interest” doesn’t equal demand.

Sadly, I think the judge's 'ability' to 'see through' this is going to depend highly on his bias.  I'm still very concerned that the judge in this case desires the banishment of leaded fuel ASAP.  As long as there is a thread of reasoning available to him, he will run with it.  I hope I'm wrong.

[Paul Thomas]

It would be interesting to see who's buying the little fuel that is still being sold.

[IvanP]

11 hours ago, Marc_B said:

I find it interesting that an email of “interest” is suggested to speak more than the fact that only 2 FBOs in California carry G100UL with decreasing demand in the sales of 200-300 gal/month.

I suspect the judge should see through this as well.  “Interest” doesn’t equal demand.

Perhaps the defese could introduce evidence of diminishing sales to support the argument that there is insuficient demand for G100UL to balance the alleged "interest" from other FBOs.

[Pinecone]

On 3/7/2025 at 8:16 AM, A64Pilot said:

No telling, good point though, anything that will dissolve Jet-Glo is a serious solvent. Problem with actual testing is it takes a long time and for metals it takes a lot more than just eye balls, like does it cause Hydrogen embrittlement in steel etc.

Except that looking at the paint damage, it appears that the Jet-Glo is intact, but the fuel attacked the primer and released the color layer.

In general, solvents do not attack metals.  You need acids or bases to do that.

[Pinecone]

13 hours ago, Paul Thomas said:

It would be interesting to see who's buying the little fuel that is still being sold.

There are a large number of planes that have not had any issues, so are likely using the fuel.

[Marc_B]

1 hour ago, Pinecone said:

There are a large number of planes that have not had any issues

I would definitely not use that descriptor.  It's an incredibly small number of planes in the fleet that have used G100UL in total and it's yet to be determined if they've "not had any issues."  Additionally, ~300-400 gallons per month is a tiny amount of the fuel sales in the area.

[GeeBee]

A friend of mine at KCVH said there is a Grumman AA-5 there leaking after using G100UL.

 

[mluvara]

45 minutes ago, GeeBee said:

A friend of mine at KCVH said there is a Grumman AA-5 there leaking after using G100UL.

 

That's the same one I referenced previously that was sitting in Hollister. See here for direct part of video.

Edited March 24 by mluvara

[MikeOH]

1 hour ago, GeeBee said:

A friend of mine at KCVH said there is a Grumman AA-5 there leaking after using G100UL.

 

Are the wings bonded/'glued' (i.e. not riveted) on those Grummans?  If so, I'd be VERY worried.

[mluvara]

9 minutes ago, MikeOH said:

Are the wings 'glued' (i.e. not riveted) on those Grumman's?  If so, I'd be VERY worried.

That is my understanding and I pointed it out in that video (if you haven't watched it). This link goes right to the references and questions of some possible connections.