Autofuel FAQ

Is the TB9 or TB10 approved for autofuel?

To fly legally on autofuel, you need one STC for the engine and one for the airframe. The problem with the TB is, that there is no sufficient airframe approval. The British CAA has some documents approving airframes and engines, but only the TB9 with O-320-E engine. That's the (low compression) 150HP engine. Also the British CAP747 mentioned the TB aircraft, but approves it just for the use of British four star Motor Gasoline to BSI specification BS 4040:2001. We have autofuel according EN228 specifications over here with no lead content, so this approval can not be used outside the UK.

We can supply the approval for the engine, but it is up to the owner to obtain an airframe approval.

Why do we use German LBA approvals, and no EASA STC

Before the EASA was founded, the Deutscher Aero Club (DAeC) validized most of the FAA STC thrue the German LBA. All STC’s accepted by EASA member states prior to September 2003 are deemed as acceptable to EASA in accordance with Article 4 of Regulation (EC) No 748/2012. Based on this regulation the LBA approvals has grandfather rights and must be accepted in all EASA member states, having the same status as an STC issued by EASA.

Is the ADI system available in Europe?

Yes it is, although only for N-registered C210. These are the models that are approved: 210 , A, B, C, G, H, J, K, L, M, N thru Serial 21064535, and fitted with the IO-520 engine. Please contact Vliegwerk Holland for more information and prices.

My aircraft is not on the list, can I fly on autofuel?

To fly legally on autofuel, you need both an airframe and engine approval. If your aircraft is not on the list, it is possible that via an Approval Notice of the CAA-UK your aircraft can be EASA approved to use autofuel.

Are fuel injected engines approved?

We don't have an STC for any engine with Bendix fuel injection. It did not past the tests. Continental fuel injection is approved for the - IO-470 -J or -K (225hp) engine. The 260hp IO-470 and 285hp IO-520 are also approved. This series of STC’s are now being supported by Air Plains Services.

I have an O-320-H2AD engine, why isn't this engine approved?

This engine is slightly higher in compression than other 160hp O-320 models that are tested. Therefore a test program only applicable to the H model would be necessary. There are not enough of them to justify the costs of these tests.

What about valves, will they tolerate unleaded fuel?

It depends. There are fifty year old specifications still being used to produce valves. These valves need a little lead once in awhile. One fillup of 100LL every 75 hours takes care of this following engine break-in on 100LL. But once 100LL is replaced by an unleaded avgas then you won't have this as an option. It is therefore critical, as these engines are overhauled, that the cylinder assemblies be replaced with parts coming straight from the manufacturer that are specifically made to tolerate the new unleaded avgas. As far as the engine is concerned, whether the fuel is autofuelor avgas doesn't make any difference, if it's unleaded it's unleaded, regardless of the name on the pump. Inquiries need to be made directly to Lycoming and Continental for parts compatible with a steady use of 100% unleaded fuel. Smaller Continentals must have lead during break in even with cylinder assemblies obtained from Continental.

Do I need to mix autofuel with Avgas 100LL to keep a little lead in the fuel?

See also above. When you overhaul your engine use 100LL for the first 25 hours to insure adequate lead during break-in period. Depending on the spec. number used during production of the valves and seats som horizontally opposed engines may not require any lead whatsoever. However since it is impossible for the aircraft owner to determine which spec. number was used on the valves and seats, one fill-up with 100LL ververy 75 hours will solve the problem regardless of the spec. number of these parts. As a general rule of thumb, if an engine has been overhauled with factory parts since 2000, then it shoulde have hardened parts which require no lead.

Are STC's transferable from one airplane to another?


Can I change my engine when I have an autofuel STC?

When changing your engine, you have to renew your paperwork. This can be done for half of the price. When changing to another configuration, you have to apply for a new approval.

Can I operate my aircraft commercially when using an autofuel STC?

Yes, the Petersen autofuel STC's has no limitations at all.

Why isn't the Mooney M-20 or Piper Comanche approved?

The Mooney and Comanche both experienced vapor lock problems when they were tested. We solved the vapor lock problem but could not overcome pneumatic lock. Pneumatic lock takes place when the fuel boils as it enters the carburetor. The engine then dies due to an over rich mixture. This is just the opposite of a vapor lock where the engine quits or runs poorly due to a lean mixture. The better an airplane performs, the more difficult it was to get it through the flight test programs.

Why is the Cessna 172RG not on the list?

It is a type that is never flight tested, hence there is no airframe STC. Two STC's are always necessary, one for the engine and one for the airframe.

My aircraft is not listed, will it be approved in future?

There are no plans to flight test any more aircraft in future.