Marc_B

Judging from SDS, I don’t see meta-toluidine listed in 100LL. And the fact that Swift has been so adamant that they don’t want fuel mixed with theirs that contains meta-toluidine (without further testing) but say 100R is fungible with 100LL, leads me to believe this is accurate reflection that 100LL does not contain meta-toluidine. (Of course there are other components in G100UL, as well as different concentrations of some components in common, not found in 100LL as well). 100LL SDS: G100UL SDS:

It's interesting that Mr. Braly has pointed towards towards Toluene and his initial posts here on MS made a point of pointing out up to 29% Toluene in 100LL. I suspect typically higher overall levels of aromatic hydrocarbons in G100UL (up to 40% xylene). However, there's allegations from other sources that it's the meta-toluidine component that's the issue. Certainly meta-toluidine is an aggressive solvent, with a boiling point of 398.1F, and the evaporation rate is considered "negligible" at room temp meaning it evaporates very slowly. Would be interesting to "test" a G100UL sample MINUS the meta-toluidine and see if it had the same effect on paint. The composition of the "film" remaining on the surface after the more volatile components have evaporated would be very informative I think. Both G100UL as well as 100LL have xylene and toluene (although in different amounts).

Not my video. But second video release on YouTube.

exactly why I posted it...is it true and what's the background? The defense statement was likely copied off of information Lycoming released, not fabricated out of thin air. But what was the context of a NDA in order for Lycoming to test fuel? I'm sure there's way more background on that we aren't privy to…and probably won’t be.

I think this hints at the liability that an owner is assuming with using a new fuel, especially with an experimental. There will always be assumptions that it was due to improper maintenance and improper construction. So there would probably be a larger "burden of proof" required for an experimental owner to recover any damages. From the "Opposition To Motion..." paper: "At present, the supplier of G100UL, Vitol Aviation (“Vitol”) warrants only that G100UL conforms to the G100UL Specification." "Indeed, Vitol appears to limit the product liability coverage it offers to the greater of $250,000 or the purchase price of G100UL, an amount that would not remotely offer sufficient coverage in the event G100UL caused a serious safety incident or significant damage to planes."

I've read some pilots question if maybe it's better to slowly integrate G100UL so that the aromatic hydrocarbon content slowly rises vs. just go from an empty tank of 100LL to a full tank of G100UL. i.e. "don't shock the seals"...Be interesting to see this studied. This may not be unique to G100UL either...i.e. we've yet to see the introduction of a fuel with dramatically lower aromatic content than standard 100LL (which may be possible with other "octane" component fuels). But it's clear that G100UL has higher aromatic content than 100LL and xylene affects seal swell to a higher degree than does toluene. But before anyone goes out and tries to switch all their o-rings/hoses/seals/etc...there's probably some knowledge we need to develop to bridge that gap successfully. https://www.cambridge.org/core/journals/aeronautical-journal/article/investigation-on-elastomer-behaviour-when-exposed-to-conventional-and-sustainable-aviation-fuels/0863C07931DFA895AC87381992D47778 "Despite the extensive volume of research on seal swell, it remains evident that the amount and rate of seal swell is highly dependent upon seal material. Adams et al. studied a range of elastomers in fuels of varying aromatic content, and those tests revealed that swell was proportional to the aromatic content." "A review of published studies on elastomer compatibility with aviation fuels highlights certain knowledge gaps which must be addressed. Standardisation for testing the complex interactions between O-rings and different fuels is available in various ASTM documents. These standards define test methods and equipment used by researchers to validate their data. However, some elastomer test methods are outdated and may not represent on-wing applications. Furthermore, knowledge gaps may also arise since ASTM standards call for the selection of single O-rings from each chemical family. An assumption is made that results obtained on the selected O-ring are representative of the entire polymer group, and this may not necessarily be valid."

FWIW. Was looking for something else and came across the email from Precise Flight customer support when I asked if other comparable lubricants/greases (specifically asked about Aeroshell 7 as I've seen that mentioned before) could be used on the PF Speedbrakes: Hi Marc, Thanks for your email. We have had customers use lubricants comparable to Aeroshell 22. However, we only recommend using Aeroshell 22. It is very important that it is not a spray lubrication and that you don't overdue the grease, usually about a pea size amount applied with a brush is sufficient.

FWIW, I previously had one of my wing sight gauges replaced with a reseal at Weep No More. Last week I reached out to Paul Beck; he typically got them from their fellow MSC, Oasis, but didn't have any on the shelf. So he added me to a list to eventually replace the other one. Not clear what a minimum order from Rochester looks like...when I reached out to Century Spring (who makes return springs for Precise Flight speed brakes) their minimum order was a 1000 springs. Curious how many different gauges are found on the various Mooney fuel tanks? May be a really long wait!

GAMI has said that G100UL was sent to Continental and Lycoming and years later was returned unopened (paraphrasing here not sure on exact details). The "Settling Defendents Opposition to Motion..." suggests that requirements of a gag-restriction was part of/the reason this testing wasn't performed. I haven't read about that before and curious if this is true and if standard practice that Continental and Lycoming could test something to be used in their engines but not disclose the results of said testing to FAA or owners...seems that would run counter to the AD/SB process if an issue was discovered. "Lycoming advises that, because GAMI insists on a “gag-restriction” that prevents it from sharing “appropriate guidance to the FAA, the industry, and the flying public,” it has not yet had the opportunity to evaluate G100UL’s “material compatibility, evaluation of toxicity, engine testing for detonation, endurance, flight testing and operability; as well as review of operational concerns to determine that [G100UL] is fit for purpose.” Hoyt Decl. ¶ 17, Ex. B." (Edit: this is also mentioned on Lycoming's webpage: https://www.lycoming.com/fuels regarding "gag-restriction.")

With regards to a pilot using a new fuel with limited fleet testing, with limited liability coverage from the manufacturer/supply stream, without an paying for and receiving a valid STC...that's just a special kind of poor ADM in my mind. (regardless of being "caught" by enforcement)

https://www.avweb.com/aviation-news/california-fuel-distributors-file-unleaded-fuel-court-defense/ California Fuel distributors file opposition to motion regarding consent decree. https://vansairforce.net/threads/rv6-fuel-tank-leak.232303/#post-1817348 Apparent RV6 with fuel leak; unknown details of builder or aircraft.

I would really appreciate seeing more side by side testing on a painted panel using common white paints with different surface prep to see how that varies in staining and protection. Given it’s been said to be a UV reaction, probably a control surface with multiple metered drops of fuel allowed to dry in full sun for a week would work. products would like tested: oxidized paint, area of paint cleaned with basic soap and water, area with paint cleaned with common products (wash wax all, wing wipe), waxed paint, ceramic coated paint, etc. Also be great if you could do those surfaces with half just G100UL dropped and let dry, and the other half with same treatments but with wiping up drops (ie refueling hygiene) instead of letting dry in the sun. Damage to, or even just staining my paint, after following basic precautions is a no-go for me unless no other choice. I’m with Don, obvious visible damage would drive me nuts. @George Braly Even if GAMI doesn’t see cosmetics as “detrimental,” it would be appreciated if there was clear information on what was tested and how those things varied in mitigation. How does one prevent damage like this?

I'm torn with this...because the VAST majority of the expense involved in ANY STC is from the product testing, development, and approval...not at all the expense of the "equipment" sold to the aircraft owner. However, charging for STC paperwork plus having to pay extra at the pump above and beyond what comparable fuel would cost seems a combination of a "fixed revenue" up front + a "royalty revenue" in perpetuity. Only GAMI knows their calculations and thought process for setting these two amounts... For comparison, Swift's STC is $100 (IIRC) for their Forever STC. How many pilots got the G100UL STC at KRHV simply due to free STC/fuel vs how many would have paid for the STC without free STC or free fuel? Of course if California outlaws 100LL and requires all pilots to pay GAMI for an STC that's a big chuck of immediate funds. So charging for the STC is like taking your winnings while you're ahead...who knows what's coming around the corner. Edit: the million dollar question is what are the fuel STC owners going to charge when 100LL is banned?? I'm sure if they offered them all for free now, everyone would go ahead and jump on board the STC to have it...so this would cut into business later on. So there's probably lots of thought in pricing from all the companies involved...

@GeeBee I don't understand how they set their price point at all as it's a significant chunk of the price of new speed brakes. I guess because they can?? It's one item that is definitely well overpriced for what's performed. Chalk it up to the good old "liability" cost category

@LANCECASPER it makes me laugh how many times the same thing is said in the same thread, in different threads, in different ways...would be fascinating to see a 1000 mile overview of Mooneyspace. Perhaps one of these days AI will allow you to type your question on Mooneyspace and will give you an answer and link the pertinent resources...oh wait, google does that already! It would be interesting for someone to "curate" all the knowledge from MS into an organized searchable "book"...almost like a POH, MAPASF PPP, IPC, Service Manual, AFMS. There are so many little pearls hiding in the threads that you sometimes have to look at "all the threads" to glean all the knowledge! I will often cut and paste info that I find that "might be important" sometime down the road...i.e. for SB I previously copied: "PF SB motor is a Pittman #GM8712-21, call 866-287-3786 I think his name was Denis. Specs 19.5:1 ratio/19.1 volts, you will have to reuse the mounting bracket from the old motor, getting the old gear off is tough the set screw may have to be drilled and taped. That's the hard part, the rest is easy. Lubricate worm drive and worm wheel with Aeroshell 22 only."

@BaileyWood-EAGLE "Through the STC process, fuel developers are solely responsible for testing the compatibility, safety, and performance of a new fuel with specific aircraft and engine models. Under the FAA’s traditional STC/AML process, an applicant is responsible for demonstrating that the aircraft and engines meet all applicable regulations and minimum standards under the normal certification process when using the new unleaded fuel. The FAA reviews the compliance data provided by the applicant and, upon approval, issues an STC." Mr. Wood, thanks for joining. Perhaps you can speak more of the FAA process for expanding Fleet Authorization as well as STC from test aircraft/engines to have an approval that is fleet wide with airframes that may not have been directly tested? I think there are plenty of us that don't quite understand the testing process, what materials are tested, how they are tested, and how this is subsequently applied to engines and airframes that seem more approval by extrapolation than direct testing. Also it would be helpful to learn how materials are tested over their service life or how determinations are made regarding addressing aging airframes that may have installed equipment/seals/hoses/o-rings/etc. that may be outside of "service life." Are these things addressed by Fleet Approval or STC? Are these determinations left up to owner/maintainers? Do you expect this will be a "fluid" process where we'll see more frequent service bulletins/advisories/changes in ICA/ADs?? Has the STC process/EAGLE/PAFI identified issues that need further testing that may not have been tested initially prior to approval, and what is the process for review and amendment of such issues? Many of us don't have a clear understanding of "what to expect" moving forward...from FAA, from STC's, from EAGLE/PAFI. So help navigating this and understanding this is appreciated.

It's the worm gear / pinon gear that needs to be maintained and lubricated. PF says that if you use spray lubricant that you "wash out" the grease that's crusty, but that it won't leave lasting protection. So there's more resistance in the worm gear/pinon gear due to crusty grease, but then (since the units are open on the top and have the ability to get rain, wash water, spilled fuel, etc. into the units that no grease protection leads to corrosion of the worm drive and more problems down the line. You have to remove the units to really get the drive gears clean, but you can reach the worm drive from the top of the unit with a standard acid brush and a light amount of grease (Aeroshell 22) as noted. BUT, I've been told that you only want to use a light amount. If you apply a heavy grease booger it just sits there and gets crusty and causes issues down the line. I wager that probably a small amount of speed brakes in the field get routine maintenance/lube annually. I suspect that most mechanics don't lube these annually unless the owner asks for it. For failure modes: what's been shared on MS usually is corrosion and failure of the return spring (it breaks). But if you don't lube them then you can have the motor wear out or causes issues with gears. Those two things are usually replaced at PF overhaul I believe. For those with the 100 series, here are some good documents to have in your files... 000S001D_Rev B_Drawing Package_08_14_2014.pdf 100 Series ICS.pdf 100 Series Comprehensive Overhaul Service.pdf 100 Series SpeedBrake Repair Service 7.22.21.pdf

The 2000 series has an asymmetric logic control unit "ALC" that prevents deployment of only a single side. The 2000 series is more "complex" and my guess is that there are more parts that are checked and replaced. But I believe that the asymmetric deployment unit is origin of requiring both speed brake units as well as the "logic" unit, so they can test them all. The 100 series are pretty basic with a motor connected to a worm drive that actuates two cams that deploy the brakes against spring resistance from the return spring.

@warrenehc to answer your question: Bravo rudder trim is independent of the KFC/Autopilot. If you install the GFC500 with Yaw Damper, you should be able to leave the rudder trim in place. However GFC500 pitch trim servo replaces your existing King electric pitch trim as that IS part of the autopilot. Long body rudder trim has L brackets (#10 below) attached to the ends of the bell cranks. There’s a spring tensioned wire (#12/13/14 below) that’s attached to the brackets that’s wound around the rudder trim servo wheel (#4 below). In these installs the Garmin YD on the GFC500 mounts differently and allows retention of the Mooney rudder trim. However on a few midbody Mooneys (I.e. the Encore) Mooney used the S-Tec rudder trim/yaw damper that can add a YD and rudder trim to the aircraft but still functions independently from the KFC autopilot. Those are also installed in the same location that Garmin GFC500 YD is installed, so must be removed to install GFC500 with YD. The interesting thing is that looking at a handful of IPCs for other midbodies including my own, and comparing to the Bravo for example…I think that the parts for the long bodies are same part numbers on the K and likely one could easily take a long body rudder trim and add it to the midbodies…if you had approval from Mooney to do so. Of course you don’t really “need” rudder trim for smaller engine/lower HP Mooneys. Just saying it looks like rudder time appears somewhat universal among Mooneys out side of the S-tec YD/Rudder trim units.

I’ve looked into service before. I wish they’d also repaint and return like new for that price. But these days that’s the only way you can get replacement return springs as PF doesn’t sell them individually any more. @TheBearFlies keep us posted what was replaced vs just cleaned and lubed when you get them back.

I tried to do that but most of those who have tried G100UL haven’t said much. We’ve had I believe 4 or so who have posted that they’ve fueled with G100UL (outside of the two with paint issues). And to be clear, the intention of the thread was only to have field reports of use rather than debate/discussion, speculation, etc. I still think this would be helpful to share what works, how to mitigate paint staining and to help show where more data is needed

I think this is a discussion of risk and liability. So far we’ve only heard that this new fuel recipe is FAA approved. You can’t know what’s in it or how it varies from mix to mix. It may or may not cause issues with paint and elastomers and it hasn’t been in use long enough to prove itself one way or the other outside of a few case reports GAMI has pointed out poor wet wings/bladders and poor maintenance are the typical causes of leaks. GAMi has pointed out that 100LL and toluene are the usual cause of paint damage. GAMI has recommended viton o-rings and Teflon lined hoses but their test data with the FAA didn’t use this and it’s a “drop in fuel” fleet wide so no modification is necessary. So any modification is left to the PIC/owner and their mechanic for determining suitability. Paint staining is known and requires “refueling hygiene” and is not considered to be damaging but rather known cosmetic issue due to fueling technique or leaks its ready to be used for those willing to use it. But the liability for any damage is assumed by the PIC/owner. There’s been no admission of any harm or damage that wasn’t already in existence with 100LL. it hasn’t been approved by Continental, Lycoming, Textron, Cirrus yet. But you can have approval from the FAA in the form of a STC that’s completed by your mechanic. This is 100% legitimate and was proven to the FAA by years of testing. Field testing and approval by the major companies will help improve individual comfort level with the product if this is shown to have good service record. Legislation is likely to escalate adoption. No need to argue points or discuss merits. Either use it or don’t. But those owners who are advocates, please use the alternative fuels to help speed knowledge and either prove a good track record or discredit it. This would be a big service to the GA community.

@802flyer look at the Surefly install manual. I believe you install it at 0 deg and the timing is controlled by the dip switches. But should be covered in the application install notes.

But at the end of the day, none of us want our paint to be damaged or stripped unnecessarily and most will go to appropriate measures to prevent this. If its known how and when you'll see damage, and how to mitigate this then you can prevent it outside of catastrophic cases of damage or spill. If the official word is that a product doesn't damage paint and you don't need to take mitigation steps, then that's an entirely different issue. i.e. if the word was that G100UL will leak and strip paint if your sealant is over 20 years old or if you have a leak, then you might choose to either 1) not use it, 2) have tanks resealed prior, or 3) use at your own risk. But the owner would assume a known risk. But having a fuel advertised as 100% drop in across the fleet without any modification may be an overstatement. Continental gives pause, Lycoming gives pause, Textron gives pause, Cirrus gives pause. This is a discussion about risk. The producer is trying to minimize risk, some people are trying to magnify risk...but we're all trying to understand risk. None of the Youtube videos or comments of this thread have better clarified this. There may be risk to elastomers, there may be risk to paint, there may be risk to valve seats...so you either trust the FAA process and jump in, you try to understand the risk so you can hopefully mitigate it, or you just say no. But FAA approval does not equal no risk. Give it 20 years and hindsight will be 20:20.

do you have a link or the highlights? Looks like it requires a subscription.