Lycoming's View: Airworthiness by Design, Not Luck
For decades, general aviation has been operating and designed around a single fuel – 100LL. Now environmental and economic pressures are driving the search for an unleaded alternative. Lycoming firmly believes that an equivalent performance unleaded aviation grade replacement for 100LL is the best total solution for our industry overall. We also know that using automotive blends in aviation is possible for certain engine models if you put the correct controls in place on the fuel. Lycoming's consistent objective is to give our customers as many fuel choices as possible while still maintaining airworthiness.
In the following three guest blogs, Lycoming specifically addresses the topic of automotive fuels for aviation, including our approval to operate certain Lycoming O- and IO-360 engines using an automotive specification fuel. Lycoming strongly recommends a thorough review of the latest revision to Lycoming Service Instruction 1070, "Specified Fuels."
Lycoming is well aware that other aviation equipment manufacturers have allowed "pump gas," in some cases with ethanol. In the details they provide warnings and cautions addressing some of the issues we raise in these articles, leaving it to the operator to assess risk in using a fuel where they do not know the core properties other than octane. We do not agree with that approach.
Two terms are used repeatedly throughout this series: "pump gas" and "mogas." "Pump gas" refers specifically to fuel that conforms to the ASTM D4814 or Euronorm 228 specifications for automotive fuel and is available for retail purchase at automobile filling stations. "Mogas" refers specifically to fuel that also conforms to the ASTM D4814 or Euronorm 228 specifications, but controlled and labeled differently such that it is "fit-for-purpose" for aviation.
Lycoming tests every engine that rolls off our assembly line. We take them into one of our test cells, attach a propeller and appropriate sensors, and then operate them through a range of tests. These tests can last from an hour up to four hours. We also use our test cells to evaluate components and new products. Every year we do this for about 3000 to 4000 engines. Lycoming purchases and consumes a lot of avgas.
So Lycoming has something in common with every owner and operator out there. We all experience pain at the pump. The price of fuel is going up for everyone, regardless of your mode of transportation. According to AirNav.com, the average price of 100LL between May 19 and July 13, 2011, was $5.79 (U.S.) per gallon in the United States, a 128 percent increase over the 2001 price of approximately $2.54 per gallon. In 2011 automotive pump gas is currently averaging $3.64 per gallon in the United States, a 254 percent increase over the 2001 low average of $1.04 per gallon. But wait, those pump gas prices are not at the aviation FBO.
According to AirNav.com, the average price for mogas at U.S. FBOs currently stands at $4.44 per gallon, a whopping 327 percent higher than the 2001 automotive pump gas price. Admittedly, these are averages and not representative of prices everywhere. Leave it to economists to figure out the comparison of 2001 U.S. dollars to 2011 U.S. Dollars, but the point is still valid. Fuel prices rose dramatically in the last decade and have made General Aviation more expensive. Coupled with the desire to move piston aviation to unleaded fuel and avgas distribution availability outside the Americas and Europe, the cost issue has created significant pressure to find ways to tap into the economies of scale that come from using higher volume lower-cost fuels like pump gas.
Lycoming's automotive gasoline approval, however, did not allow pump gas. We simply can't approve pump gas for our existing products if the first objective is airworthiness. What we did approve is a fuel from the pump gas production sources that is controlled well enough to provide predictable behavior on the engine. Airframers would need to do the same. Lycoming believes companies advocating the distribution and use of automotive gasoline in aircraft ought to consider the same controls. This is airworthiness by design.
The Lycoming mogas is an option for the fleet that could use low- octane fuel. It might be less expensive than 100LL – but we all know that retail price and production costs are two different things. We also know that the "free" services provided by our FBOs need to be covered somehow. In the end the Lycoming mogas is a low-grade aviation fuel from automotive blend stocks. The same angle was previously attempted more than a decade ago with the ASTM 82UL avgas effort. You might have noticed that no FBO offers 82UL. That's an indicator that even when presented with an option, demand has not been sufficient to support a two-grade aviation gasoline fuel system.
Environmental challenges, price pressures and availability are all considerations for every owner and operator. It's the reason why Lycoming approved mogas, but it's not pump gas. It's an unleaded option that could be considered for aviation, but we fear the applicability is too low to be a universal solution and you will pay a premium over pump gas. It's the reason why we've publicly called for – and actively support the efforts towards – an unleaded replacement fuel for 100LL.
In our plant, we evaluate our performance as a business using five metrics. Four of those metrics are ranked and in order they are Safety, Quality, Delivery and Cost. The fifth is Leadership and Teamwork. Safety comes first and Cost comes last in the ranked items. We applied that same philosophy to our mogas approval where we designated the specification of pump gas such that we arrived at Lycoming's mogas. That is how we achieve Airworthiness by Design, rather than by luck. We did it and did not publicize it because our fifth metric, Leadership and Teamwork, demands that we consider all the angles, and we did not conclude that industry and owners would be best served by a distractive argument on mogas because in the end, it's a low-grade aviation gasoline with what we feel is limited broad application.
Concluding and as stated in our previous articles, Lycoming's goal as an engine manufacturer is to provide as much fuels flexibility for our customers as possible without compromising airworthiness. A mogas option could be possible for the existing fleet, but it's not pump gas. In the end, we all agree that Airworthiness by Design is the objective.
The ongoing dialog regarding the distribution and use of unleaded automotive fuels in aviation needs to be solidly based upon this consideration and the subjects raised in this three-part series. You'll find many of the same considerations in the FAA's Unleaded Avgas Transition ARC charter. These considerations are why Lycoming continues to believe that piston aviation is best served by pursuing an unleaded aviation specification fuel to replace 100LL.