Review of Alternative Fuel Initiatives for Leaded Aviation Gasoline (AVGAS) Replacement

Abstract

Tetraethylead (TEL) is an additive in aviation gasoline (AVGAS) fuels to help suppress knock. Knock produces very high pressure inside the engine which can cause severe damage easily. Without the addition of TEL, the octane levels will be too low for some engines. Using a lower octane fuel than required level could lead to engine failure in piston aircraft engines. This is because Piston aircraft engines operate at higher power settings and temperatures. Friends of the Earth (FOE) filed a ‘‘Petition for Rulemaking Seeking the Regulation of Lead Emissions from General Aviation Aircraft Under Clean Air Act” to conduct a finding that lead emissions from general aviation aircraft endanger public health. FOE insisted to issue a proposed emission standard for lead from general aviation aircraft under the Clean Air Act (CAA). In 2008, EPA decreased the level of the primary National Ambient Air Quality Standard (NAAQS) for lead from 1.5 micrograms per cubic meter (µg m^-3) to 0.15 µg m^-3 in order to provide increased protection for children and other at-risk populations against an array of adverse health effects. In this study, a comprehensive review will be conducted to analyse the replacement fuels introduced or tested or in use around the globe that has been used to further reduce or totally eliminate TEL from avgas 100LL. This paper assists aviation research students to further research and gain comprehensive knowledge on AVGAS, the problems on AVGAS and alternative fuel initiatives around the globe. If replacement for leaded fuels are tested and proven for drop-in replacement, the general aviation community can continue to thrive for decades to come with a renewable resource that is cleaner for the environment. Lead emissions should also be given equal concentration along with emissions of carbon dioxide, carbon monoxide, oxides of nitrogen and other particulates emissions in aviation with proper studies and findings to help the elimination ef