Auto-gas STCs

Fearless Tower

Fearless Tower

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Fearless Tower
This is probably more of a trivia question than a practical one, but an auto-gas STC should follow the engine rather than the plane, correct?

In other words, if a plane had an auto-gas STC, but the engine was later replaced with a different engine, that STC would no longer be valid, correct?
 
i think the auto gas STC's i've seen are for specific airframe/engine combos.
 
tonycondon said:
i think the auto gas STC's i've seen are for specific airframe/engine combos.
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That would make sense....I was just looking through some records and found one in the 337 file....however, the C-145 engine was later replaced with an overhauled O-300, hence I don't think it is valid anymore.

Out of curiousity, what 'modifications' are typically involved in an autogas STC?
 
The follow on question, though, is this - doesn't the engine changeout require a 337?

I know the O-300 is an approved engine for the C-170, but there is no corresponding 337 in the FAA file on the aircraft. Shouldn't there be?
 
Fearless Tower said:
That would make sense....I was just looking through some records and found one in the 337 file....however, the C-145 engine was later replaced with an overhauled O-300, hence I don't think it is valid anymore.

Out of curiousity, what 'modifications' are typically involved in an autogas STC?
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The autogas STC on my cherokee was invalidated when I installed the 160hp upgrade engine STC and airframe STC.

iirc, the autogas STC on my cherokee was really just a paperwork exercise.
 
The AutoGas STC that most people have was a paperwork issue. I believe EAA did it, and it was effectively just something that allowed you to use automotive pump gas (without ethanol) in planes that were originally certified for 80/87. A friend of mine has it in his 182 with a low-compression O-470.

To my knowledge, there are no STCs out there that allow use of current automotive pump gas with ethanol in certified aircraft.
 
The Mogas STC follows both airframe and engine. To qualify for an STC the airframe components of the fuel system have to prove compatibility with Mogas (hoses, seals, etc.) and the engine's fuel system must also comply. The chemisty of Mogas is different enough that some materials suffer with it.

Dan
 
Fearless Tower said:
The follow on question, though, is this - doesn't the engine changeout require a 337?

No, unless the engine has a major alteration.

I know the O-300 is an approved engine for the C-170, but there is no corresponding 337 in the FAA file on the aircraft. Shouldn't there be?
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No, because it is alternate engine on the type certificate. as is the 165 horse Franklin.

no alternation, because the aircraft still meets the type design.
 
Tom-D said:
No, because it is alternate engine on the type certificate. as is the 165 horse Franklin.

no alternation, because the aircraft still meets the type design.
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So all that would be required is the log entry?
 
Dan Thomas said:
The Mogas STC follows both airframe and engine.
Dan
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not true, it is applied to the airframe as equipped from the factory, you change the type design, the STC no longer applies.

All STCs applied to the aircraft must be compatible. read the STC instructions.
 
Fearless Tower said:
So all that would be required is the log entry?
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Yes as far as the engine is concerned
" removed engine S/N ____ and installed engine S/N ___ this date and bla bla bla....
 
Petersen will charge you some extra bucks to issue a new tag and paperwork for the engine. You install the tag, make a log entry & send in the new STC 337 and presto the airplane can use auto fuel again.

Paul
N1431A
2AZ1
 
Dan Thomas said:
Petersen has them certified separately. When we bought them we got an STC for the airframe and another for the engine model.

http://www.autofuelstc.com/autofuelstc/pa/Approved_Engines.html

http://www.autofuelstc.com/autofuelstc/pa/Approved_Airframes.html

Dan
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The Auto fuel STC is applied to the aircraft, simply because the engine does not have a history records at OKC. N number is what the faa tracts.

your reference is from the STC holder, (not the faa) and is only for their customers reference
 
Dan Thomas said:
Petersen has them certified separately. When we bought them we got an STC for the airframe and another for the engine model.

http://www.autofuelstc.com/autofuelstc/pa/Approved_Engines.html

http://www.autofuelstc.com/autofuelstc/pa/Approved_Airframes.html

Dan
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Q.Since the 0-360 is approved, and the Cheetah and Traveler are approved, why isn't the Grumman Tiger approved?

A. The Tiger was never flight tested. The approvals from the Cheetah and Traveler cannot be extended to the Tiger because the fuel flow on the 0-360 is a little higher than on the 150hp and 160hp 0-320's. Hence a flight test program for the Tiger would be necessary.

no matter which engine, the aircraft must be tested.
 
Tom-D said:
The Auto fuel STC is applied to the aircraft, simply because the engine does not have a history records at OKC. N number is what the faa tracts.

your reference is from the STC holder, (not the faa) and is only for their customers reference
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Well, from what I got from Petersen when I called and talked to him there was more too it than that. They issue to the aircraft also because some airframes require modifications as well like boost pumps above a certain altitude and some of them have hoses that need to be changed out due to material incompatibility and such.

Also, from what he was telling me each requires a couple of test flights and climbs with precisely heated fuel. If the flights go well (he told me the exact parameters but I've forgotten since) then it's rather simple, but some planes need boost pumps added and some don't manage, but as soon as you have to do mods, it involves at least a DER and those costs to develop the STC.
 
Henning said:
Well, from what I got from Petersen when I called and talked to him there was more too it than that. They issue to the aircraft also because some airframes require modifications as well like boost pumps above a certain altitude and some of them have hoses that need to be changed out due to material incompatibility and such.

Also, from what he was telling me each requires a couple of test flights and climbs with precisely heated fuel. If the flights go well (he told me the exact parameters but I've forgotten since) then it's rather simple, but some planes need boost pumps added and some don't manage, but as soon as you have to do mods, it involves at least a DER and those costs to develop the STC.
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Isn't that What I said?

The Holder of the STC can make of it as they wish, it's them and their customers.

Auto gas STCs were developed on the aircraft as delivered from the factory, The engine is but a system in that aircraft, change that, and the STC no longer applies. Example the C-150 auto fuel STC was for the 150/0-200 It will not apply to the C-150/150 until testing is completed for that combination.

if the airframe must be modified, the STC will tell you how and where it is done.
 
Tom-D said:
Isn't that What I said?

The Holder of the STC can make of it as they wish, it's them and their customers.

Auto gas STCs were developed on the aircraft as delivered from the factory, The engine is but a system in that aircraft, change that, and the STC no longer applies. Example the C-150 auto fuel STC was for the 150/0-200 It will not apply to the C-150/150 until testing is completed for that combination.

if the airframe must be modified, the STC will tell you how and where it is done.
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Ok, yeah, The way I read it was saying that the reason the STC was tied to the aircraft was because it was the only way to track it to the engine. I was just adding that there were other implications to the airframe besides the engine.

BTW, he did offer up the use of his heating tank to do the test on anything they don't have an STC for.
 
I recently ordered an ethanol test kit to start testing some local gas. I hear how some pumps labeled no still have some ethanol mixed in. This is the kit where the gas turns blue if ethanol is present.
 
sourdough44 said:
I recently ordered an ethanol test kit to start testing some local gas.
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I heard of people using Alka-Seltzer to test the gas. From what I understand, if the gas has ethanol, it will also contain water, which will make the tablets fizz.
 
This is another thing nice about experimentals, no STC's needed. Burn what you want. I have over 6,500 gallons through my homemade tank saving around $10,000 over 100LL.

fuel_tank.JPG


I change the dual filters twice a year and change the hoses every other year. There is a sump tester on the bottom of the tank, but I just look in the top for water accumulation.

There are cautions however. Mogas should not sit in your plane or your storage tank for more than 2 months. It can start to loose octane in 30 days, and gum up the fuel system. Use 100LL for long term storage or add Sea Foam (fuel preservative) and run the engine for 1/2 hour.
 
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Fearless Tower said:
In other words, if a plane had an auto-gas STC, but the engine was later replaced with a different engine, that STC would no longer be valid, correct?
Click to expand...

It all depends on what you mean by "different". If you are changing the engine like the Polish army changes underwear (Wiznewski changes with Dumbrowski, Prezioproski changes with Zambrowski, etc.) where you are merely changing one engine for an identical engine (model, suffix, etc.) then the STC is still valid.

If you change engine$ to a different model or suffix, then the $TC require$ updating.

Jim
 
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