On December 3, 2013, Shell has become the first major oil company to develop a lead-free replacement for aviation gasoline (Avgas 100 and 100LL), and will now begin a strict regulatory approvals process.
Shell’s new lead-free formulation comes after 10 years of exhaustive research and development at facilities in Chester, United Kingdom and Houston, Texas, as well as successful initial testing, carried out in the fall of 2013 by two original equipment manufacturers (OEMs).
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 has a motor octane rating of over 100, an industry standard.
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 Lycoming Engines for bench tests, and Piper Aircraft, Inc. for flight tests.
Shell will now engage the aviation industry, regulators and authorities, including the Federal Aviation Administration, 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.
Avgas is one of the last common transportation fuels to contain lead.