One of the questions I wanted answered at this year’s AirVenture in Oshkosh was “what is the latest on unleaded avgas?” To find out, I did numerous interviews and attended several seminars.
The big news was the immediate introduction of a 94 motor octane unleaded avgas by Swift Fuels. The fuel will be marketed with Petersen Aviation since the product meets the requirement of all of Petersen’s STCs.
The fuel also meets ASTM D7592, ASTM D7547 and ASTM D4814. D4814 is the general spec for auto gas that is listed in the Petersen and Experimental Aircraft Association‘s STCs for auto gas. The D7592 spec is for a fuel that is basically 100LL without the lead. D7547 is basically the same and is being used by European refineries for markets in other countries.
Officials from Swift Fuels were listing all of the attributes of the new product and the work needed to develop it. I then asked if it was just 100LL without the lead and they finally admitted that that was basically what it was.
Now, I applaud their efforts and feel that they will sell some product. My first question, though, is why did they not just say that it also meets ASTM D910 for an 80/87 fuel since that spec lists only a maximum of 0.5 G/Gal TEL with no minimum? That would mean that they could sell it to all pilots with 80/87 engines with no STC.
The other concern is cost. I know that everyone thinks that an unleaded fuel will be significantly cheaper because it can be shipped by pipeline vs. 100LL which cannot. But the fuel is still going to be a boutique fuel and will need to be handled in dedicated facilities to keep it in spec. This means that the cost will be very close to that of 100LL, which may reduce the volume of sales.
Along with Swift, I also talked to officials with Shell and General Aviation Modifications Inc. (GAMI) about their respective 100 Motor Octane unleaded fuel candidates. I will address the GAMI interview in a later column.
Shell and Swift are both working with a cooperative group to develop a drop-in 100 Motor Octane unleaded fuel. They are working with the FAA, EPA, ASTM, and a bunch of other alphabet groups. The group has identified three candidate fuels for further testing (two from Swift and one from Shell). The two Swift candidates are “pure hydrocarbon” fuels and the Shell candidate contains an anti-knock additive system.
The program will look at a multitude of performance characteristics and then do flight evaluations. The end goal is to have the fuel or fuels approved for use in all Continental and Lycoming engines, and probably also Rotax and other Light-Sport Aircraft (LSA) engines.
Does anyone see a problem here? What about the Pratt & Whitney engines, as well as the Wrights and other orphan engines out there in the fleet? Their answer to that question was that “they” will get to them later. But who is the “they” that will do the work, who will pay for it, and — most important — who will stand behind the answer and assume liability for any problems?
The other problem is when they approve the unleaded fuels, who will sell it? FBO’s will have the option of selling mogas, 94UL, 100UL or 100LL, all at about the same cost. With only one fuel system I would probably bet on them staying with 100LL because it is the only one to work in all aircraft.
One of the most surprising observations at Oshkosh came from several sources that I consider people who understand the “show.” They all felt that there was a change in the attitude of the aviation community regarding the “unleaded fuel” problem, which used to be a “gloom and doom attitude.”
It was unanimous for this group: They were all optimistic that, in the long run, 100LL is not really going to go away for quite some time.
It is definitely worthwhile to stick around just to see what happens next.