Vitol Aviation, which has more than a million gallons of General Aviation Modifications Inc. (GAMI) G100UL unleaded avgas for sale, is disputing claims by the National Air Transportation that the fuel is not ready to be sold. In a statement last week, NATA said that without a fuel specification from ASTM International, which GAMI has chosen not to pursue, fuel suppliers and retailers “lack assurances that the unleaded fuel they are selling will not expose them to liability” and the fuel therefore cannot be considered “commercially available.” But Vitol says it has had no problem getting insurance for its handling of G100UL, the fuel has been fully tested and vetted and it fully intends to bring it to market.
“Vitol Aviation is proud to have brought the first 100 octane avgas to market, which is fully compatible with all FAA certificated engines without modification,” Vitol said in a statement to AVweb. “G100UL is has an FAA-approved specification, is tested according to ASTM standards, and fully available under standard aviation fuel contract terms.”
Vitol said in a statement to AVweb. “G100UL is has an FAA-approved specification, is tested according to ASTM standards, and fully available under standard aviation fuel contract terms.”
If this statement is true, Why is NATA saying it is not “tested to ASTM standards?
There’s a difference between being “tested to ASTM standards” and “having an ASTM specification”.
Hmmm. If the ASTM specification differs from the FAA-approved specification and someone knowingly flew with it and had an accident, wouldn’t they be criminally liable? It seems to me, an ignorant cuss with no law degree, the FAA specification is the law of the land that ASTM would have to copy as a minimum standard.
So please educate me.
ASTM standards are “a means of showing compliance, but not the only means”. This statement is included in all ASTM standards. I know, because I have been chairnan of an ASTM subcommittee for a long time.
An FAA STC is as good as an ASTM standard. Hence, the GAMI G100UL is good to go; no ASTM standard specification needed.
+1. I am on ANSI and ISO technical committees and the same is true for those standards.
This dispute is the epitome of the “not my idea” phenomenon, except is also involves money.
And you can bet money that even if G100UL DID have an ASTM spec, NATA/EAGLE would find some other reason to claim that the fuel isn’t “commercially available” or whatever silly wording they’d come up with.
All I would like to know is “where can I go to buy a tank of G100UL?” Until I can exchange cash for gas, to me it’s not really “commercially available.”
I understand that Vitol is saying “we have it and distributors or airports can buy it,” but until the PIC can taxi up to a G100UL pump or truck somewhere, it’s not quite “available” IMHO.
In California, various airports have signed an agreement to stock 100UL when it becomes “commercially available” – that is, available on the wholesale market, not at the pump.
Certainly I can see a secondary market as racing fuel; most race gas has lead in it, as well.
to expound on Marten’s answer, the part 23 rewrite, and the AD alternative means of compliance (AMOC) come to mind. Regarding the ASTM D910 spec for leaded gasoline: “This specification covers purchases of aviation gasoline under contract and is intended primarily for use by purchasing agencies. This specification does not include all gasoline satisfactory for reciprocating aviation engines, but rather, defines the following specific types of aviation gasoline for civil use: Grade 80; Grade 91; Grade 100; and Grade 100LL. The gasoline shall adhere to octane rating requirements specified for individual grades, as follows: lean mixture knock value (motor octane number and aviation lean rating); rich mixture knock value (octane and performance number); tetraethyl lead content; color; and dye content (blue, yellow, red, and orange). Conversely, the gasoline shall meet the following requirements specified for all grades: density; distillation (initial and final boiling points, fuel evaporated, evaporated temperatures); recovery, residue, and loss volume; vapor pressure; freezing point; sulfur content; net heat of combustion; copper strip corrosion; oxidation stability (potential gum and lead precipitate); volume change during water reaction; and electrical conductivity.” (from ASTM website, where they sell the full document for $75.00)
All you need is one missing item, such as fuel color or lead content, to “not meet the standard”. As the specific gravity of G100UL is different than any other aviation fuel, it likely would need a standard of its own. Hjelmco is basically forced to add a bit of lead to its unleaded fuel to meet ASTM D910.
From Hjelmco’s website: Hjelmco unleaded AVGAS 91/96 UL is made to and meeting the requirements in the US standard for aviation gasoline ASTM D910, grade 91/98. As lead is mandatory in the standard D910, unleaded AVGAS 91/96 UL is not free of lead. The amount of lead is however so trifling it fits into the definition of being unleaded i.e. < 0,002 g/liter.
NOTE the ASTM states the spec is primarily for PURCHASING MANAGERS! Government wishes to be assured that it is getting the product it asked for, even if it costs too much!
So; by the comment immediately above, NATA wants to force GAMI to put a miniscule amount of lead in the fuel to make it meet the ASTM “Standard”?
One has to agree with the earlier comment that NATA would find some other excuse to refuse the fuel.
Perhaps the NATA personnel have ingested too much lead?
How about if I fill my tanks with G100UL, and sign my gas receipt with a lead pencil? Will that work?
Sure, if you can a pencil that actually uses lead.
(I use a #2UL).
I see what you did there. That was slick as graphite. 😎
Nope. G100UL has a density that is outside of all of the current unleaded avgas ASTM specs.
I believe that to be the primary ASTM issue for GAMI.
ASTM D7547 is the one to read for Unleaded Avgas. (like UL91 and UL94)
Previously there was ASTM D6227-10, a spec for UL82 and UL87. (I have never seen either)
Just because an ASTM spec exists, does not mean the fuel will ever be available, however!
ASTM D439 is one automobile standard, and the one used to develop most Auto fuel STCs. It was replaced with D4814. Most of us who use autofuel test the fuel for ethanol, as well as volatility, because neither spec prevents the use of oxygenates, though D7547 does.
I’m afraid it is far more complicated than that.
D910 is a hydrocarbon fuel including TELB which has to meet a range of property and performance requirements (meaning all of the base fuel only contains hydrogen and carbon, so no oxygenates, no manganese, no amines etc etc). Hjelmco’s fuel is essentially the same base fuel components, but almost lead free (and so the consequence is 91 Motor Octane Number). If we really stretch the ‘hydrocarbon only’ base fuel composition we can just about meet the D910 performance properties and achieve 94 MON. Nothing higher.
To get an unleaded fuel higher in octane than that, something else has to be used as an octane booster in the fuel: something that has never been used in civil avgas before. Something that needs checking. Properly.
For example D910 does not control flame speed as a property as the other property definitions in D910 constrain the hydrocarbon composition in such a way that the components used don’t result in huge changes in flame speed (so for example the fuel density limits in D910 might appear only affect how much the fuel weighs, but in fact it also indirectly controls the aromatic content as aromatics are heavy – so D910 AVGAS 100LL can’t have aromatics above about 25% and commonly is below 15%).
Let’s run with this aromatic example even though it is a class of hydrocarbon and not as different as some of the novel components that must be being used in the 100+ octane fuels. Some aromatics burn really slowly, so if we put a lot of them in a formulation, then we need to check a host of other things that result from having a slow flame speed (Piston ring sealing, oil dilution, EGT, TIT, creep life of exhaust valves, pre ignition, prop vibration etc etc). And across a range of engines right?
If we change something else, then we need to do further testing.
This is all laid out in ASTM with their guidance document for approving Avgas fuels and additives (ASTM D7826 if you want to go and look at it). So this is the significance of getting an ASTM spec: it forces that protocol to be followed. Further, the work that EAGLE does on assessing compatibility with non aircraft systems is important (e.g. fuel supply infrastructure)
And if it is done under ASTM, then it is all visible and transparent.
With proprietary testing it is all invisible and mysterious.
In fact for fuels with Intellectual Property granted (such as G100UL) it is actually illegal for anyone else to make or test that fuel without GMAI’s permission unless the fuel is procured commercially (and as no product is available commercially, the IP owner can thereby continue to control any and all the testing).
As a pilot I have been following this closely as many have, but with having some knowledge in this space this YouTube clip caught my attention (fast forward to 20:00 and listen carefully).
https://youtu.be/kB6g9bvumj0?si=0GZzM6AbIWrp6O14
Ask yourself why would a company go to the expense and complication to develop its own detonation protocol (and to be careful to keep that a secret as is clear in the interview) when FAA already has a detonation protocol that it uses for engine certification? The only reason I can think of that I would go to those lengths is if my fuel failed the existing FAA protocol right?
Now I might be reading too much into this and it also might be ok to move the goal posts to approve a specific fuel, but it’s a hint that things are different with these high octane fuels and we simply judge how different, or what testing has or has not been done, when everything is proprietary.
I’m always skeptical when the only assurances that something is ok are coming from the person trying to sell me that something
Well, there’s some history here, and until we know it fails the FAA test the assumption I would make is he thought the FAA wasn’t testing properly. So far, I’m unaware of anything GAMI has disagreed with the FAA on which the FAA, or the industry in general, turned out to be right on.
There is no subterfuge in GAMI’s detonation detection protocol. It simply uses technology that was not available with the original single cylinder variable compression test engine designed so many decades ago. Gami uses a pressure sensor integrated into the spark plug, and that is not the only way to determine propensity to knock.
Using ion sensing, peak combustion pressure at any given crank angle can be measured as well as knock, and ideal timing of the peak pressure event can be determined by measuring current flow across the spark plug gap after combustion is initiated. This technology is in place in millions of automobiles. Ignition timing can be adjusted on the fly, between firing events for a single cylinder. One can even see the number of knock events on each individual cylinder, over a given period of time, in the engine data stream. Various adjustments can be made, such as boost level, cam and ignition timing, fuel mixture etc. to manage knock.
One of the FAA methods for determining detonation is the 150 full throttle test run, followed by engine disassembly. GAMI can know what those results will most likely be in a few hours or less. Why wait for an engine failure just to start the test protocol again.
https://image.slideserve.com/787472/ion-sensing-ignition-l.jpg
The single engine test you’re referring to is presumably the ASTM D2700 Motor Octane method which will still be used as its needed as a quality control test for the fuel. It isn’t the demonstration of the fuel’s suitability in engines and isn’t the protocol that has been replaced right?
The detonation testing in full sized engines is the question.
In my mind I’m still being asked to believe that the inconvenience of stripping an engine in your answer (if that is what is needed in the existing FAA engine detonation tests – I’m not even sure if it is or not) is more problematic than the cost and complexity of a 15 month project to define a new, proprietary detonation test method.
Why would I do that obviously arduous and trail blazing work if my fuel’s detonation performance is equivalent to 100LL in the FAA’s tests especially as I’m likely going to need to strip engines anyway to look for other things (valve seat recession, engine wear, valve stems etc etc)?
Something about it still doesn’t seem right to me.
Perhaps GAMI can make a clear statement that the fuel did perform as well or better than Avgas 100LL in all the original FAA tests and my mind will be eased, but no test data is available outside of the IP holder and the FAA (who presumably are under a non disclosure agreement) and so only the fuel formulator chooses what to share.
This is the problem with proprietary testing – a lack of clarity.
This pissing match is emblematic of what continues to plague the process of bringing aviation in line with fuels that have been available for five decades. NATA of course doesn’t want the words “Fully Available” attached because then by law they’re obligated to start carrying it in markets where it’s available. GAMI went STC to avoid the delays of the FAA’s latest “program”, and predictably now we’re seeing the failures in EAGLE already.
It’s almost like all the cross-fighting among bureaucrats, airport owners, and pilots is designed to perpetuate status quo. Gee who’d have ever thought that the aviation community would do all in its power to resist any change.
Who is responsible if this isn’t so good for engines and fatal crashes occur.
Who is responsible for the same when the pilot was using an autogas STC? Or any STC, for that matter.
Autogas is different. The forecourt seller is not consciously selling it for use in aircraft and he is not marketing it as suitable for aircraft. So they are not liable for someone deciding to make an arrangement with the FAA to use a fuel that may not be suitable for aviation use.
Aviation fuel is specifically marketed for aviation, so if it is not suitable, it is a fair question to ask who is liable.
The IP owner (shallow pockets)? The FAA (unlikely as they are not an applicant)? The STC owner (likely the injured party, so …)
The fuel producer (deeper pockets)?
First two are the only parties that have visibility of the approval work, so I can imagine a litigation lawyer asking a fuel producer what due diligence they did to assure themselves that the fuel that they are producing as an aviation fuel is suitable for aviation use?
Right or wrong, this is what some companies are obviously contemplating at the moment.
When the EPA finally gets their way (and they will) do you think they are going to allow any amount of lead in ANY gasoline, aviation included?
NATA President Curt Castagna also EAGLE chair putting a halt on GAMI sounds like a conflict of interest it doesn’t smell right! What’s the real reason I suspect $$$.
Just keep complaining till the Feds eliminate piston aviation. It will be Jet A, electrons or nothing.
>> If GAMI’s G100UL is tested to ASTM standards, why is NATA saying it is not tested to ASTM standards?
NATA is not saying that. NATA is saying that GAMI’s unleaded avgas spec was developed by GAMI with the FAA, not with ASTM. However, the GAMI/FAA developed spec is defined in terms of ASTM standards. It’s just that the spec itself is not ASTM reviewed.
>> where can I go to buy a tank of G100UL?
At this point, Vitol in Baton Rouge, LA.
>> G100UL has a density that is outside of all of the current unleaded avgas ASTM specs.
The current ASTM avgas spec does NOT specify a fuel density. The spec only requires that the density be reported. GAMI’s fuel varies, though, in distillation end point and amine content. GAMI spent a dozen years working with the FAA to prove that those variations do not have any negative impact on aircraft or engine performance.
>> D910 AVGAS 100LL can’t have aromatics above about 25% and commonly is below 15%.
Some current D910 avgas blends are over 30% aromatics, per test data from last week.
>> this is the significance of getting an ASTM spec: it forces that protocol to be followed. Further, the work that EAGLE does on assessing compatibility with non-aircraft systems is important (e.g. fuel supply infrastructure)
And GAMI and the FAA did all that as well in their dozen-year G100UL certification effort.
>> And if it is done under ASTM, then it is all visible and transparent.
Maybe not. The PAFI development efforts have been shrouded in secrecy, even though tens of millions of our taxpayer dollars have been involved. The FAA won’t even release the standards to which they’re testing those fuels. On the other hand, if you can read the publicly available patents, and GAMI’s regular updates, you can understand completely what’s in their fuel and how they have qualified it for airworthiness.
>> for fuels with Intellectual Property granted (such as G100UL) it is actually illegal for anyone else to make or test that fuel without GAMI’s permission unless the fuel is procured commercially
All of the PAFI fuels, from Swift, Shell, Phillips, and Lyondell/VP-Racing, have associated intellectual property. However, it is NOT illegal to make or test those fuels, if you can puzzle out the composition. It’s only illegal to *sell* such a fuel without permission of the IP owner. You can even make it for your own consumption, if you are so inclined and capable.
>> as no product is available commercially, the IP owner can thereby continue to control any and all the testing
That’s patently not true… I’m almost certain that each of the fuel developers has been using publicly available information to synthesize and test their competitors’ fuels. Certainly, they’ve made comments and asked questions indicating they’re doing just that.
>> this YouTube clip caught my attention
>> if a another company comes in and wants to produce this fuel they bring their own test protocol which the FAA oversees and approves, it may be similar to yours by happenstance, or it may be different, and still get to the same place
>> why would a company go to the expense and complication to develop its own detonation protocol (and to be careful to keep that a secret as is clear in the interview) when FAA already has a detonation protocol that it uses for engine certification? The only reason I can think of that I would go to those lengths is if my fuel failed the existing FAA protocol right?
Or, as has been discussed in ASTM meetings, the FAA protocol, an ASTM-adopted standard, contains math errors that make the results erroneous. Rather than relying on erroneous results, some companies might choose to get FAA adoption of a true and correct protocol. Assume that the intention would be to share the protocol, once the competitive edge dissipates. But in the meantime, an enormous amount of time, effort, and expense would go into gaining FAA acceptance of the true and correct protocol.
If the development work of ASTM detonation protocols happened to be flawed, who is more likely to discover that than someone seeking to certify a new fuel?
>> I’m always skeptical when the only assurances that something is ok are coming from the person trying to sell me that something
Fortunately, we have the FAA in the loop here, also providing those assurances.
>> Why would I do that obviously arduous and trail blazing work if my fuel’s detonation performance is equivalent to 100LL in the FAA’s tests
If the FAA’s ASTM-adopted test has flaws, as discussed at ASTM, then who would want to use a flawed test to certify their fuel? Keep in mind that not all developers may have yet detected that flaw.
>> Perhaps GAMI can make a clear statement that the fuel did perform as well or better than avgas 100LL
GAMI has in fact stated that… that in real aircraft engines, their G100UL performs better than 100LL in every relevant respect. Others measuring with crooked yardsticks may reach different conclusions.
>> Who is responsible if this isn’t so good for engines and fatal crashes occur.
Under strict liability, everyone in the fuel design and fabrication chain would share liability, as determined by a competent court of jurisdiction.
>> The IP owner (shallow pockets)?
All those involved carry substantial liability insurance, backed by Lloyds of London, they’ve said.
>> Right or wrong, this is what some companies are obviously contemplating at the moment.
Perhaps. Or, perhaps the resistance to change and fear of being first is causing folks to spread fear, uncertainty, and doubt in an effort to kick the can down the road. After all, the FAA launched their search for the unleaded avgas solution in 1991, 33 years ago. Can kicking has become an art form.