Autogas for GA

[Ozgrade3]

The new Piper website list one of their Archers did a 2,000nm round the US using 93 octane motor fuel. A similar spec to the 93UL that's coming.

I know theres a few Lycomming 320 & 360 engines that are certified for mogas. But what is "mogas". Is it from a specialist refinery or do you just call BP and order 100,000 litres of BP Ultimate.

What other things would have to be considered if a flying school wanted to go mogas.........apart from STC's. Can you mix mogas with regular 100LL. At a guess you would save 50 cents a litre and using 100,000 litres a month is not small change.

[Old Akro]

Here you go:

Petersen Aviation | Auto Fuel STC (http://www.autofuelstc.com)

I think most of these were done before 98 Octane and most apply to engines designed for 80/87 Avgas, so 91 Octane is adequate.

MOGAS is out of the pump from your local service station, but ethanol is a no-no. So you should stick with a branded high volume site and run an ethanol test.

[Ozgrade3]

Thanks Akro,

Very interesting website. Interestingly no fuel injected models seem to be listed. Is there an inherent problem with the stoneage injection systems with running mogas?

Also, pump gas at the average servo is something like 50% tax, applicable to road users. Farmers are able to claim a diesel rebate for vehicles that don't use public roads.....I'm quite sure an aircraft wouldn't use a public road:hmm:

So I need to find a way to buy large amounts of fuel without the road tax component.

[Jabawocky]

WARNING

93AKI is equivalent to our RON 98 in other words BP98 or Caltex Vortex 98 and NOTHING LESS.


DO NOT GET CONFUSED.

The other problem is that mogas of the lesser grades has all sorts of compounds in it, and the amount of olefins in it can be a serious problem. Ask me how quick I can remove, clean and refit 3 x carbies on my near new V6 Yamaha outboard. Yes 2hours! Lost of practise, all from gum deposits (olefins) and usually I use Caltex 98 except on odd occasions. :*

So is it worth it? In my opinion no way.

The piper story is about a dedicated "Aviation grade auto gas" and if you think every FBO in Australia or the USA is going to stock such a thing and a 100 MON grade with both at a reasonable price.....think again.

Hang in there with 100LL for just a little longer until the G100UL is available. :ok:

Any questions fire away, happy to help as best I can. :)


PS: Typical min spec 100LL is about 101.5MON in order to get the 130 Rich mixture rating, can be a little less but basically to compare that to the AKI ratings it would be 106.

[Jabawocky]

Is there an inherent problem with the stoneage injection systems with running mogas?

YES

Check PM's for a phone number to call ;)

Anyone else wanting to learn a bit about this topic, I will devote a small amount of time over and above the normal APS Engine Management Made Easy course content to answer questions and discuss what is and is not possible and happening in the industry, and I can do that far better than a post on the internet. Only a few seats available.

[ForkTailedDrKiller]

Ask me how quick I can remove, clean and refit 3 x carbies on my near new V6 Yamaha outboard.

2-stroke sh*t !

Shouldda bought Yammie 4-stroke. :E

Dr :8

[RatsoreA]

Jaba,

Long time viewer of fuel replacement threads, first time poster on the subject...

Genuine questions, and I don't mean to sound flip about it, if that how it comes out....

Question the first - When? Precious little other than 'soon'. Even if approval etc were issued tomorrow and everyone said, yes, it's fine, use it, you'd think there'd be 12-18 months at least before I was able to feed my TSIO-360KB and it's brother just that diet!?

Question the second - Vapour pressure. Mogas of any flavour has awful vapour pressure properties, compared to AvGas. Will G100UL suffer from this? The engines that are glued to my draggy airframe much prefer being up high and passing the workload off to the turbos!

And please correct me if I'm wrong, but doesn't some premium fuels (98RON) still have an ethanol content?

[Old Akro]

From the Autofuels website FAQ

We do not have Auto Fuel STCs for engines using Bendix fuel injection because it failed our flight testing. Continental fuel injection did not have that problem and is therefore approved – I0-470-J or -K (225hp). The 260hp I0-470 and 285hp I0-520 are also approved. These last two require Anti Detonation Injection (ADI).

It seems they tried a whole range of aircraft and only obtained STC's on those which ran well without modification. I think many others could be converted easily (technically), but might be difficult in a regulatory sense. By this I mean that getting the sort of fuel pumps you want that are TSO approved and then getting the plumbing changes approved might just be a bridge too far.

I THINK that if you look at the CAFE foundations early work you might see some research on MOGAS too.

A thing about fuel is that we import lots of it, most of which is bought on the spot market in Singapore. Fuel imported in that way can be a lottery. In Australia, 91 octane is refined by: Shell, Mobil, BP & Caltex, although Caltex will cease soon. 98 octane is refined by BP, Shell & Mobil. If you buy 98 octane from anyone else its source is uncertain. The inground tanks from which the fuel is dispensed is also an issue. Old ones take in water and contaminants. The new fibreglass ones are best. Which is why I think its best to buy from a high volume BP, Shell or Mobil site.

Australian fuel improved dramatically about 8 years ago when (for the first time) we introduced National fuel standards. You can download fuel Technical data sheets from the fuel companies & the govt fuel standards web sites. In the old days we needed to import batches of fuel for European vehicles because our fuel was inadequate (mainly due to sulfur content)

Fuel also varies in formulation a number of times throughout the year depending on where you are in Australia. Different companies use different schedules. Its primarily about ease of starting. We sometimes have special batches of Winter European fuel refined for vehicle testing here. Among western countries, country to country differences are mainly about vapour pressures. Although I've had to research fuel in Afghanistan and the peculiar Indonesian 88 fuel, both of which are entertaining. If you were really fussy, you'd try and buy summer formulation for aircraft because of its higher vapour pressure.

Octane rating is a bit of a minefield. There are 4 or 5 different ratings. Octane rating is still pretty much determined in the same manner that was created by Sir Harry Ricardo in the early 1900's. This is basically to use a single cylinder engine and increase the compression ratio until it "knocks". This point can be influenced by mixture, which in simple terms leads to the difference in ratings. AVGAS & road fuel use different ratings. Most of the MOGAS STC's are based on 87 or 88 AKI fuel with some of the higher compression ratio engines requiring 91 AKI fuel. So, most are likely to be OK on Aussie 91 Octane.

Its also worth noting that in Australia the published octane rating is a minimum. Fuel from the pump is frequently higher (esp 91 octane).

Personally, I would use 98 octane because its specifications are tighter and I think (without justification) that you are less likely to get a shandy of fuel or traces of toluene, ethanol and other (illegal) cheapening agents. BP 98 Octane fuel is sporadically exported to California. We make pretty good fuel here now.

And for Jabba, I'd be questioning where he buys the fuel for the boat more than the fuel itself. The fuel from some country stations which still have old cast iron tanks can be a nightmare.

[Old Akro]

but doesn't some premium fuels (98RON) still have an ethanol content?

You can easily get the 98 octane fuel Technical data sheets from the BP / Shell / Mobil websites. Those ones don't use ethanol. However, outside that you are on your own and good luck getting technical data.

[Jabawocky]

Akro....fuel purchased around the Brisbane area, but at times 98 has not been available. :sad:

I have very good friends who tweek the knobs and dials at two major refineries in Australia, if they had surplus strawberry jam in the refinery and could stick that in the 91 ULP......THEY WOULD!

Even with the Aussie fuel standards, the spec is very broad.

[Jabawocky]

RatsoreA, hope these do the questions justice, no need to bite though! ;)
Jaba,

Long time viewer of fuel replacement threads, first time poster on the subject...

Genuine questions, and I don't mean to sound flip about it, if that how it comes out....

Question the first - When? Precious little other than 'soon'. Even if approval etc were issued tomorrow and everyone said, yes, it's fine, use it, you'd think there'd be 12-18 months at least before I was able to feed my TSIO-360KB and it's brother just that diet!? Well there is a time frame that depends on regulation or just commercial pressure. Of course if Innospec went broke, had a massive industrial accident, change would be faster, but in the case of the likely candidate UL fuel, the changeover for a refinery is not hard or complex and could be done in 6-12 months. What happens here will depend on what happens in the USA.

Question the second - Vapour pressure. Mogas of any flavour has awful vapour pressure properties, compared to AvGas. YESWill G100UL suffer from this?No not at all. The spec for G100UL is identical to Avgas. The engines that are glued to my draggy airframe much prefer being up high and passing the workload off to the turbos!

And please correct me if I'm wrong, but doesn't some premium fuels (98RON) still have an ethanol content? Not that I am aware of, or certainly the BP98 does not. Tiny amounts of Alcohol is useful in avgas or G100UL for that matter, but it is tiny amounts for specific uses.

You will have much better engine health as a result :D

[Old Akro]

Akro....fuel purchased around the Brisbane area, but at times 98 has not been available.

Jaba, Caltex don't refine 98 octane, so the fuel you buy is coming from somewhere else. Could be bought from Shell, or could be bought on the spot market out of a range of overseas refineries, or could be a mix of both. I'd switch to BP, a Shell or Mobil 98 for the waterborne fleet.

[MarkerInbound]

The 260hp I0-470 and 285hp I0-520 are also approved. These last two require Anti Detonation Injection (ADI).


Water injection on a CE-402, that'll be interesting.

[Jabawocky]

Akro, I suspect it is BP from Bulwer Island. Caltex in Brisbane have a refinery but I doubt they produce it.

You did ask where I was buying it.....not who I thought was making it. And truly that could be from anywhere even with the majors. Shell shipped 98RON from their now closed Clyde refinery up here not that long ago.

And hence the trouble with mogas in aircraft, you just can't be sure and there is no requirement to give you surety.

[Walter Atkinson]

IMO, any replacement fuel that requires that high performance engines be altered or modified to successfully use it is dooming the GA fleet. It must be a drop-in replacement. GA cannot withstand that kind of expenditure for no gain.

[Jabawocky]

Water injection on a CE-402, that'll be interesting.

Walter is right as he usually is. Add to the above, what do you do with water injection in a twin? Added weight = less payload and what do you do when you have a missed approach and run out of water? :uhoh:

As I understand it they are not able to be used for part 135 operations anyway.

My comments on another thread;
What is critical besides the required performance parameters and material compatibility is that you can swap from one to the other and blend them in any ratio in the wing or the FBO tanks. Anything else than complete 'blendability' with existing 100LL is not going to work for the period of time it takes to change over. This is no easy task, and if it was easy, it would have been done long ago.

In summary any replacement for 100LL needs to be;
1. MON99.6 and supercharge rich rating of 130, or higher.
2. RVP of 5.5-7.1 PSI
3. Must not require modification to the aircraft/engine (read certification)
4. Must not have a derating of HP, most twins would be grounded if so
5. Needs to produced in sufficient volume to be rolled out across the USA, Canada, Brazil, Australia, Europe etc.

[Old Akro]

From the EAA 13 years ago.

http://www.eaa.org/autofuel/autogas/articles/1Autogas%20vs%20Avgas.pdf
(http://www.eaa.org/autofuel/autogas/articles/1Autogas%20vs%20Avgas.pdf)

http://www.eaa.org/autofuel/autogas/articles/1Autogas%20vs%20Avgas%20Part%202.pdf

[Jabawocky]

Not bad articles, except the old wives tails :rolleyes:
Lead is also used to provide lubrication of upper cylinder components such as valves, pistons, cylinder walls and valve guides.

Lastly, we emphasized the im- portance of having updated valve train components in any engine in which autogas was going to be burned. Modern valves, guides and seats are more tolerant of the absence of lead so that they will not burn up prematurely.

engine manufacturers have identified high upper cylinder and valve wear as a problem when unleaded fuel is used during the break-in process.

When an engine cylinder is repaired or overhauled, an owner should be certain that the latest style, high quality valves, compat- ible valve guides and valve seats are installed that are designed for use with 100LL fuel. As an additional benefit of the new hardware, the valve train is more tolerant of unleaded fuel use.
After repairs to cylinders are ac- complished such as grinding valve seats, valve refacing, or installing replacement parts such as valve guides, it is important to break in these new parts for approximately 25 hours with leaded fuel to provide some lubrication before using lead-free fuel.

Then to contradict the statements above
This fuel has been approved for use with certain models of Lycoming engines (including engines that originally used 91/96 octane avgas) and is now being used in certified aircraft in Sweden.
The recent unleaded avgas operations with this specific unleaded fuel have been very promising with up-per cylinder and valve wear. It is important to differentiate this fuel from automotive fuel.

I wonder why that is? Could it be no lead thus no deposits that are abrasive.

Folks when reading these articles remember not to become part of the OWT's that have almost been killed off, but seem to resurface far too often!

[Old Akro]

I'm sorry, I don't mean to be difficult, but if we are going to dismiss OWT's, lets do it with proper peer reviewed technical papers.

This is probably the best:
Valve Problems with Lead Free Gasoline (http://papers.sae.org/710368/)

Influence of Low Lead Fuels on Exhaust Valve Performance (http://papers.sae.org/710674/)

But if you don't want to pay the SAE money, here are some others:
http://www.unep.org/transport/pcfv/pdf/VSR-FinalDraft.pdf

http://www.martinwellsco.com/skin/frontend/default/martinwellsco/downloads/MWI-ValveWearStudyReprint.pdf

http://www.diva-portal.org/smash/get/diva2:639359/FULLTEXT01.pdf

p13 of the final reference says By removing lead from
the fuels in order to facilitate catalytic converters and reducing atmospheric
lead pollution, the beneficial tribofilms from the lead component was removed
and the wear of some critical engine components accelerated dramatically
[4,5].

The conclusion from all of these is that lead plays a role in creating a coating on the valve seat which reduces wear which in turn is evident as valve recession. This is not evident in road vehicles because of advances in the design of valve seat profiles and valve seat materials. Valves rotate at about 360 deg every 3-5 seconds. These features are (I think) incorporated in some aircraft engines, but not all. One of the problems of aircraft engines is that there hasn't been significant design iterations since the 1960's when this issue was first being understood. By comparison there have probably been 10 design iteration of automotive engines in that time. My 1972 Alfa Montreal incorporates hardened valve seats which means that it happily runs on unleaded fuel. Changing to unleaded fuel for vehicles has not been such an issue because the valve design is so much better in modern cars than aircraft.

I do understand that many aircraft engine manufacturers have changed the design of valve inserts to make them more tolerate of low lead / lead free fuels, which is probably the missing link between the 2 statements that you think are contradictory.

[Jabawocky]

I disagree with your conclusion Akro, the last document is the only one that even mentions it but if I were to be critical it refers far more often to oil deposits in the tribofilm. They fell for the owt themselves. Not unusual.

The other four seem to be debunking the OWTs effectively. They almost don't believe in valve recession problems at all. They do support everything Walter or myself have posted. Thank you :ok:

Time to revisit a post by Walter a few months ago. Point 6 in particular.

A few things that ARE in harmony with the laws of physics:

1) Lead does NOT slow the burn rate of avgas. It increases the latency, which is the time it takes for the flame front to become organized after the spark event. This is why it suppresses detonation. After the flame front is organized the flame front moves at the same speed with or without the lead.

2) The iso-octane study done by the FAA took two NEW engines, one on the right, one on the left in a twin. One engine was run on 100LL; the other on 100 octane (iso-octane) with no lead. After several hundred hours, there was NO difference in the wear patterns in the two engines. NONE. This proved that lead had no effect on wear or exhaust valve life or performance. Lead is NOT needed in ANY way to help valves. Period. Parade Rest. It is used ONLY to widen the detonation margin.

3) The reasons seats were changed in auto engines when unleaded fuel came about was that the existing seats were not hard (like aircraft engines have always had). These issues are not in any way applicable to aircraft engines.

4) 100 octane unleaded fuel performs exactly like 100LL. Why? If you remove the lead in 100LL it is not 100 octane.

5) John Deakin is right. Everything he says about this topic is in harmony with Taylor, Haywood, and all other known sources of DATA, including the most advanced engine test facility in the world.

6) Many SAE papers on the topic of the effects of lead in combustion are flawed in that the studies did not control for internal cylinder pressures (which ARE the cause of the observed problems).

7) Healthy exhaust stains are a very, very light tan (almost whitish) because this indicates that the engine is being run at BSFC(min) mixtures (LOP).

I have data to support all of the above. I have been showing it during the APS classes for over a decade to thousands of pilots, mechanics, OEM engineers and combustion engineers from the engine manufacturers. Not once has anyone taken issue with the hard data or presented any contrarian data.

If you have any contrarian data (respectfully, no opinions, please) I would deeply appreciate seeing it.

If you would like to see this data, we will be presenting it in Ada, Oklahoma in October and Sidney in November (I think it's November--can't recall at this instant).

It seems as though everyone has an opinion on this topic, but it is worth remembering that the data has no opinion. It is what it is.


Lastly, the BP98 and quite likely the Caltex, comes from Bulwer Island. I was talking to my mate who actually makes it and the RON coming out tonight was 105. They will throw other junk in to get rid of it and meet the dumbed down 98. I wonder where the gum comes from :hmm: even in the good stuff.

[Old Akro]

My studies of fuel are a couple of years old now, but I did a lot of work on it for the worlds #2 car manufacturer. This included interviewing the head fuel technologists at a number of the oil companies. At the time BP only made 98 at Kwinana, but things might have moved on.

While BP may supply Caltex in QLD my point is that its not exclusive and if the spot market is favourable it will be substituted with Singaporean fuel. Also BP supply California with fuel from time to time depending on US supply and exchange rate, so there are times when BP does not have any excess capacity to supply other brands.

For my money, I only buy BP, Shell or Mobil and only from high volume sites. I also frequently have to supply fuel specifications to clients and my experience is that BP, Shell & Mobil have the most easily accessible specification sheets and have accessible fuel technologists when I require specific clarification. In the past we have also conducted batch testing of commercially available fuel from a variety of service station sites. As I noted earlier, the quality between different service station can be significantly different.

Having said that, the United 98 octane is very good and the guys next door get more power on engines on the dyne than the BP racing fuel. But, it contains ethanol, so its neither suitable for aircraft or any of my cars.

Regarding aircraft valves, I cannot disagree more. Get an old aircraft pot and take it to a race engine guy or cylinder head modification guy and ask what they think. The valve seat profile (ie seat angle and the contours leading to and from the seat) is very old fashioned. The UN paper talks to this, which is why I included it.

This is what Continental say:
In such fuels, the lead acts as a lubricant, coating the contact areas between the valve, guide, and seat. The use of unleaded auto fuels with engines designed for leaded fuels can result in excessive exhaust valve seat wear due to the lack of lead. The result can be remarkable, with cylinder performance deteriorating to unacceptable levels in under 10 hours.

I forget the timing, but at least Continental made a change to its valve seat material a few years ago. Car engines started moved to hardened seats and modified valve profiles in the late sixties / seventies, but it really got going in the late eighties when catalytic converters became mandatory, which is why the reports such as the 2012 UN one don't report problems moving to unleaded fuel, as I said I included it because of its very nice explanation of seat design. Aircraft engines started changing seat materials sometime after 2000. The problem is that many GA aircraft can have engines with over 20 years calendar life and therefore are in the pre-hardened seat era.

The FAA AVGAS transition committee is concerned about valve recession of replacement fuels and deems testing of this as required.

[/URL]

Peterson Aviation (who hold 20,000 MOGAS STC's) and who are probably the major proponent of unleaded fuel say:
However, lead has also been found to protect valves and seats against valve seat recession.

This Swedish paper agrees

https://gupea.ub.gu.se/bitstream/2077/2839/1/gunwpe0019.pdf

The crucial
question is therefore whether or not a car with soft valve-seats can use unleaded gasoline.
This matter has been under heavy investigation. It seems to be a matter of interpretation since
conclusions differ between studies, the results are coinciding. One fact that
researchers, oil companies, and vehicle salesmen agree upon is that only 0.05g lead per liter is sufficient to prevent VSR (McArragher et.al., 1994).

This paper by Barlow:
[URL="http://www.emeraldinsight.com/journals.htm?issn=0003-5599&volume=46&issue=6&articleid=876693&show=ref&PHPSESSID=iqjstp2eupnqjq9ftu2tl0jj32"] (http://www.faa.gov/regulations_policies/rulemaking/committees/documents/media/Avgas.ARC.RR.Appendix.2.17.12.pdf)

says: "The lead compounds, oxide and sulphate mixtures resulting from combustion proved to be the most effective lubricant for cast iron or unhardened valve seats ever produced. here is also another less well documented but none-the-less crucial benefit, ie the lubrication of the bottom of the valve guide...."

The previous papers are based on the Swedish experience which was the first country to phase out leaded fuel in the 1980's. The paper by Barlow documents real world engine wear examples from removing lead which include valve seat wear, valve burning and turbocharger wear. I hadn't read this before, but apparently lead forms a protective coating on the turbocharger impeller.

Here's another one
http://www2.isye.gatech.edu/~vthomas/elimination_lead.pdf

A secondary role of lead additives is lubrication of the exhaust valves.

The most extensive study of the car maintenance consequences of using unleaded gasoline in cars designed for leaded gasoline was a 5-year study of 64 matched pairs of cars (62).

cylinder heads were replaced more often on the cars using
unleaded gasoline,because of excessive valve-seat wear

Laboratory studies confirm that under prolonged, severe driving conditions,valve-seat recession will occur if unleaded gasoline is used in engines without hardened valve seats

[Old Akro]

And from Shell itself

AVGAS Facts and Future - Shell Global (http://www.shell.com/global/products-services/solutions-for-businesses/aviation/aeroshell/knowledge-centre/technical-talk/techart12-30071515.html)

s you may know from the problems with Automotive fuels, Lead compounds from TEL form a protective layer on the valve seat and prevents the soft valve seats from eroding. Without TEL small areas of a soft metal valve seat will fuse to the valve and be 'plucked' from the face of the seat.

Once attached to the valve they form an abrasive surface which further damages the valve seat. This combination of actions is known as Valve Seat Recession (VSR) as the seat of the valve is worn away and recesses into the cylinder head. The solutions to this are to either use a VSR additive or fit hardened valve seats which are resistant to this action.

VSR additives are now commonly used in Lead Replacement Petrol on automotive forecourts, however for several reasons they are not yet approved for use in aviation engines. This means that the only current method of preventing Valve Seat Recession for aviation engines using unleaded fuels would be to fit hardened valve seats. This is common in new manufacture Avco Lycoming and Teledyne Continental engines, but some older engines would need modification.

[Jabawocky]

So explain why when the radial piston ag guys started using ULP (to save a $$) and started having valve issues in their old design heads, they then did nothing but change the timing.....and their problems went away.

No lead....less in fact as it would have worn away, and still the problems went away with timing changes.

The same thing for many cars.

In any case.......in GA aircraft it is a moot point.

[Old Akro]

No lead....less in fact as it would have worn away, and still the problems went away with timing changes.

That's dealt with in a couple of the papers. I think the Barlow one is best from memory. From memory its about changing the temperature profile of the valve and it also derates the power of the engine.

Mogas also has other additives to replace the lubricating properties of lead to some degree. It is not without lubricating properties entirely. I haven't paid a lot of attention to it, but I think Potassium is one and MTBE may be another - although it is controversial, and I suspect that the industry may have moved to something new. I forget what was behind Shell's move from Optimax to V-Power, but involved a wholesale change to the fuel's chemistry.

[Old Akro]

Swift Fuels gains ASTM approval - Aircraft Owners and Pilots Association (http://www.aopa.org/News-and-Video/All-News/2013/November/11/swift-update.aspx)

Swift fuel ATSM approval

[Volumex]

Swift fuel ATSM approval
The fuel didn't get ASTM approval. The D 7719 ASTM specification got approval to go from a testing specification to a production specification.

Having said that, I just checked the type certificate for the Victa and it states "Fuel: 80/87 minimum grade aviation fuel." and nowhere does it nominate which standard that fuel must conform to.

Seems no reason it can't use 100SF or G100UL now. They are both aviation fuels and both have octanes greater than 80/87. If I was stupid enough to ask CASA they would say no, but might be better to seek forgiveness than ask permission.

[Jabawocky]

What does the POH say about fuel or in section 2? ;)

Just because it says 80/87 that is not the end of it. The ASTM is an industry standard and in no way reflects a FAA approved fuel. ASTM is irrelevant in terms of its aviation approved status.

FAA have to be dealt with first.

Trust me on that;)

In fact legally you need only one of the two approvals, and it sure ain't the 4 letter one.

[Jabawocky]

From George W Braly
When we look at this problem - - we boil down the issues to a set of design requirements for a workable replacement avgas for 100LL.

Design Requirements for a Functional Drop-In Replacement for 100LL Avgas:

1) Detonation - - same-same as 100LL;

2) Material compatibility - - close or same-same as 100LL;

3) Economics - - close to 100LL. Close means ? ~ about 10-15% premium or less;

4) Fungible. Has to be mixable in the FBO tanks and the wing tanks. Otherwise a transition to a new fuel becomes a logistical nightmare.

5) Producible. Has to be able to be made inside the fence of existing refineries. Nobody is going to spend 100’s of millions to build new production facilities. This requirement is related to item 3) above; and,

6) Transparent. Has to be transparent to the pilot, the engine, & the airframe when compared to 100LL.

Frankly - - we can do an assessment of five of those six requirements in two or three days of testing at our facility. The material compatibility testing takes longer, but even that is subject to some pretty straightforward assessments.

But then actually doing all of the formal certification work is challenging.

All of the testing todate continues to demonstrate that G100UL(R) avgas meets each of those six requirements.

Swift decided to pursue an ASTM specification - - hoping then that someone will decided to undertake the expensive and time consuming work to do all of the FAA certification testing to actually get the fuel approved to that it can be added to the limitations section of the engine and airframe type certificates, then legally flown in the aircraft.

GAMI has taken a different approach. We decided to do a parrallel process. We are doing the heavy lifting certification work with the FAA. At the same time we have the ASTM process moving forward. The data we generate for the FAA certification effort can be used for most or virtually all of the ASTM data package. But the ASTM data package does not get you an FAA certification.

We continue to make good progress with the FAA certification effort. At the same time, we continue to move the ASTM specification approval process forward.

Regards, George