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INDUSTRY INSIDER 30 airportbusiness October 2014 the fuel combusts in an engine. But the biggest questions are more long term. How does the fuel handle itself when it's exposed to fuel handling equipment, storage systems, and distribution over decades? WHAT SAFETY ISSUES DID YOU HAVE TO MEET IN DEVELOPING THIS FUEL? This has to do with the initial tests with the OEM. The engines are usually pretty straightforward because, for the most part, they're metal, so they're not that sensitive to fuel chemistry over short durations. For airframes, it's obviously a different story because they're going to be flying. The typical path you would take is to test the fuel against all of the fuel wetted components. Anything that's in that aircraft that would come in contact with the fuel needs to be tested for compatibility. Depending on the OEM, sometimes we do that testing here and sometimes the OEM does that testing at their location, and we just ship the fuel to them. That's where the safety checklist comes in before we can fly. There are two parts to this: One, we essentially need a note from the engine man- ufacturer that the fuel is suitable for that engine, so it's not going to detonate. Then we need the materials compatibility data. If they do their own testing, they're going to convince themselves. If we have to do it, we need to put together a report then have a series of calls with them where we walk them through the data, answer their questions, and perform follow-up experiments to demonstrate compatibility that is sufficient for their airframe. It's quite a process, and it can take upward of a month or so to iron out all the questions. WHERE IS SHELL'S REPLACEMENT FUEL IN THE APPROVAL PROCESS? There are two parts to the regulatory approval process. The FAA ultimately does the certifying. The FAA involves the American Society for Testing and Materials. The ASTM has a sub- committee that looks after fuels and lubricants, and within that subcommittee, there's another subcommittee that looks at aviation and where these specifications fall. If you think about the current product, the ASTM D910 specification, that's an ASTM spec- ification. What the FAA does is say, "All right. That specifies the fuel." That tells you the compo- sition the fuel might have, its physical properties and such, and really defines what the fuel is. Then the FAA takes that specification and certifies it. That's how it works, they're hand in hand. We're obviously pursuing both in parallel. We are working through ASTM, and there are two steps there. There's a test specification, which is a preliminary step. It just gives some definition of the space that our fuel chemistry looks at but it's still very broad because as testing goes on we may need to modify or make some changes here and there. It gives us that flexibility. Then once we complete that testing, we go into what's called a production specification. That's the final piece. We're generating the data now to go after that production specification. In parallel to that, the FAA has their own program that started on July 1, where a number of companies submitted proposals to enter that program and then at the end of August a smaller set of companies was invited into a phase of that program. This program is designed for certification of the fuels. In the FAA's, very near-term view, it appears that this is the primary vehicle to achieve cer- tification, which is why we're participating in that. There are two phases. One revolves around materials compatibility, physical property testing, and so on. The second phase involves engine and airframe testing. The idea behind that is to gener- ate the data sets required to support certification. HOW FAR OUT DO YOU THINK WE ARE FROM HAVING AN ALTERNATIVE FUEL? That is the real crystal ball reading. We are attempt- SHELL'S FLIGHT PATH TO UNLEADED AVGAS SHELL became the first major oil company to develop a lead-free replace- ment for Aviation Gasoline (Avgas 100 and 100LL) in December 2013, after which the fuel began a strict regulatory approvals process. Avgas is one of the last common transportation fuels to contain lead and is used by light aircraft and helicopters. Shell's new lead-free formulation comes after 10 years of exhaustive research and development, as well as successful initial testing, carried out in the last two months by two original equipment manufacturers (OEMs). Xinsheng (Sheng) Zhang, vice president of Shell Aviation, says: "We are proud of this first for Shell Aviation. This advanced product is the latest milestone in our long history of innovation. We believe that with industry support, a stringent approvals process can be completed for this new lead-free product within a short time-frame. We look forward to working alongside our technical partners and authorities to progress the necessary approvals needed to make this product a reality for use in light aircraft engines of all types." Avgas currently includes lead in its formulation to meet fuel specifications and boost combustion performance (known as Motor Octane rating). Shell has developed an unleaded Avgas that meets all key Avgas properties and that has a Motor Octane rating of over 100, an industry standard. The development of a technically and commercially viable unleaded Avgas that meets these criteria has been seen by the aviation industry as a significant chal- lenge, due to the tight specifications and strict flight safety standards that it has to adhere to. To get to this stage, Shell Aviation technologists carried out an intensive internal laboratory program, including in-house altitude rig and engine testing. Working alliances were then formed with aviation engine manufacturer Lycoming Engines and the light aircraft manufac- turer, Piper Aircraft Inc. As a result, the formulation was successfully evaluated in industry laboratory engine (bench) tests by Lycoming and in a flight test by Piper. Shell will now engage the aviation industry, regulators and authorities, including the FAA, American Society for Testing and Materials (ASTM) and European Aviation Safety Agency (EASA) to achieve approvals for the unleaded Avgas. Shell expects to also work with other OEMs to continue the testing and refinement program as the approvals process progresses.