A broad-based and sustained commitment across the aviation industry, along with the FAA and other government agencies, is necessary if significant progress is going to be made on reducing lead emissions from aviation-gasoline-powered aircraft, according to a new report released by the National Academies of Sciences, Engineering, and Medicine.
Developed by a Committee on Lead Emissions from Piston-Powered General Aviation Aircraft with the support of the Department of Transportation, the congressionally-mandated report found that questions surrounding current efforts to develop a drop-in replacement unleaded aviation fuel mean other steps will be necessary to begin reducing lead emissions and exposures.
While the FAA has worked with the industry on studying potential drop-in replacements through the Piston Aviation Fuels Initiatives, that program is now years behind the initial goal of having testing completed on potential candidates by late 2018 as early leading contenders required further study. Research has continued on potential candidates.
“The committee came to realize that currently there is no individual, certain solution to the aviation lead problem, and therefore a multi-pathway mitigation approach offers the greatest potential for tangible and sustained progress,” according to the report.
Meanwhile, the report makes a number of suggestions to help alleviate the reliance on avgas and mitigate the impacts. Among the recommendations is that the FAA should work with the Environmental Protection Agency, Occupational Safety and Health Administration, and aviation organizations to develop education campaigns, provide training, and raise awareness on lead hazards and potential mitigation measures for pilots, airport personnel, and aircraft technicians.
Also, the report notes that the only specified and available unleaded avgas, UL94, has the potential to be used in about half to two-thirds of the existing piston fleet. However, this would require expensive infrastructure changes and aircraft recertifications. As such, the report stressed effort is needed to motivate fuel refiners to reduce the amount of lead added to high-octane aviation gasoline, suggesting that the FAA explore policy options to accomplish that, as well as prompt airports to add infrastructure to dispense more unleaded gasoline.
Further, the report recommends the easing of recertification requirements for aircraft that do not require high-octane fuel to encourage pilots to use lower octane fuel. A timeframe should be set for these efforts, it says, suggesting this might require a congressional directive.
Elimination of lead from all aviation fuel must remain a public policy priority, the report emphasized, calling on the FAA to continue collaboration with industry and agencies such as NASA to continue its research.
Progress is crucial because general aviation aircraft are now the single-largest emitter of lead in the U.S., the National Academies notes, citing concerns that these emissions can be inhaled by people living near or working at airports.
“Because there is no known safe level of lead in the blood, there is a compelling reason to reduce or eliminate lead emissions from small aircraft,” said Amy Pritchett, professor and head of the department of aerospace engineering at Pennsylvania State University and chair of the committee that wrote the report.
The report recognizes that lead is necessary to provide the requisite octane levels for many high-performance piston aircraft and also notes the critical societal functions these aircraft play, from medical airlifts, aerial firefighting, business transport, crop dusting, pilot training, and search and rescue. “Due to the small market for aviation gasoline and limited fueling infrastructure at most of the country’s more than 13,000 airports, leaded aviation gasoline is usually the only fuel available to operators of small aircraft,” the National Academies said. For that reason, the committee decided that restricting use by high-performance aircraft is not a viable option.