While the introduction of additional grades of fuel was a sound strategy for the reduction of lead use in the automotive industry, there are serious challenges to and concerns with the application of that strategy to aviation. Increased costs, lowered availability, and decreased safety combine to make a dual-fuel solution, or transitional solution, to the issue of lead use in aviation unworkable.
On Jan. 10, 1973, the Environmental Protection Agency (EPA) required that unleaded fuel for automotive uses be made available by mid-year 1974. This requirement began a process that ended in 1996 when the EPA finalized rules for a complete ban on the use of lead in automotive fuels. The 1973 requirement created a dual availability of leaded and unleaded automotive fuel, a strategy that has been suggested as a solution to reduce the amount of lead used in general aviation. The stark differences between aviation gasoline (avgas) and automotive gasoline usage and distribution, however, make this strategy impossible.
In a dual-grade avgas environment, on-airport fuel service providers, known as fixed base operators (FBOs), would experience significant negative effects in addition to the possible higher cost from supply terminals. FBOs currently have storage capabilities for one grade of avgas and would be required, due to the need to segregate different grades of aviation fuel, to construct or purchase additional infrastructure to handle additional unleaded grades. This additional infrastructure would include storage tanks, filtration systems and associated piping, and fuel delivery vehicles. Many existing airport or FBO storage facilities have been designed for current needs and would not have room for additional storage tanks. These facilities would need to be completely redesigned or separate facilities for the new grade of avgas would need to be built.
In addition to infrastructure costs, FBOs also would face additional manpower costs. Unlike its automotive counterparts, aviation fuel and the equipment used to store and handle it must undergo a continuous regimen of quality control testing and inspection. Each storage tank or fuel delivery vehicle must undergo specific daily, monthly, quarterly, and annual inspection to maintain compliance with industry standards. A single tank or fuel delivery vehicle can require up to 214 man-hours or more per year to maintain quality standards.
The introduction of multiple leaded and unleaded grades of avgas also presents significant operational and safety issues. As airports, supply terminals, and FBOs make business decisions as to whether to carry both grades of fuels, the result could likely be reduced availability of certain grades of avgas at specific airports. This patchwork of fuel availability stands to impose significant burdens on aircraft operators, as those operators eliminate from use airports not carrying the correct grade of fuel.
From an FBO perspective, a leading safety concern is misfueling. Misfueling refers to the delivery of the incorrect grade of fuel, or incorrect quantity, to an aircraft. Misfueling is a serious safety concern and has led to aircraft accidents in the past. The industry has worked hard to eliminate misfueling through the use of selective spouts and aircraft filler ports. The introduction of a second grade of avgas would reintroduce the serious dangers of misfueling. Aircraft requiring lead could be subject to serious engine damage or failure in the event that the aircraft was inadvertently fueled with unleaded avgas.