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7 Conclusion
Pages 125-138

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From page 125...
... The importance of reducing lead pollution motivates the development and implementation of mitigation measures to reduce or eliminate lead emissions from general aviation (GA) aircraft.
From page 126...
... Some fuel suppliers have been working independently to develop avgas alternatives, resulting in at least one grade of unleaded avgas that can satisfy a portion of the piston-engine fleet that does not require fuel with high octane, and a grade of avgas that has a lower lead content that can be used by all piston-engine aircraft. Meanwhile, advancements continue in the development of lead-free propulsion technologies for small aircraft, including diesel, turbine, and electricpowered systems.
From page 127...
... by 2017, but the agency did not meet its target date.6 The uncertainty surrounding a proposed endangerment finding from EPA complicates assessments of the array of policy options that are, or may become, available to mitigate aviation lead pollution. Given that uncertainty, the committee did not consider regulatory tools that might be issued by EPA under the CAA.
From page 128...
... While development of a drop-in unleaded fuel that can satisfy the entire piston-engine fleet is a highly desirable goal, attainment of that goal is not assured, and a singular focus on achieving it risks the neglect of other opportunities to reduce lead emissions from GA aircraft and subsequent human exposures. Assessing the feasibility and effectiveness of the airport-specific application of potential mitigation measures in mitigating hot spots for ambient lead concentrations would benefit from an improved understanding of individual airport characteristics.
From page 129...
... Workplace lead exposures include not only inhalation of airborne emissions, but also inhalation, ingestion, and dermal absorption of the fuel additives TEL and ethylene dibromide as a result of aircraft refueling and maintenance activities. Occupational Safety and Health Administration (OSHA)
From page 130...
... This suggests that a multi-pathway approach that pursues lead emission and exposure reductions is needed in which the development of a drop-in fuel proceeds as a part of broader mitigation pathway focused on the development and deployment of leadfree fuels and new propulsion technologies, in combination with mitigation pathways focused on airport operations and practices and on existing fuels and aircraft. Pursued simultaneously, these pathways would differ in their potential to yield near-term reductions in lead emissions and exposures and present different implementation requirements and levels of certainty about effectiveness.
From page 131...
... Timeframe for lead Near-term Near-term Near- to mid-term Mid-term Far-term for ap- Unknown; may Far-term; pace of reduction benefits if preciable reduc- require technical reduction depends started soon tions and will breakthrough on cost, rate of require technical innovation, and advances extent of applicabil ity to GA fleet Focus of implemen- Airport manage- FAA flight Fuel supply chain, Fuel supply chain Engine and air- Fuel supply chain, Technology detation ment standards, especially refiners and airports, craft makers especially fuel velopers, aircraft pilot instruction especially fuel developers and manufacturers, and and training storage and dis- engine and aircraft aircraft owners programs, GA pensing capacity makers community Possible policy ac- Provide data and Provide training Directives and/or Incentives and fi- Directives and/ Public–private R&D support, tions for facilitating tools for analysis and education incentives, perhaps nancial assistance or incentives collaborative FAA certification, implementation and identify- materials; en- focused on refiners for airports to applicable to GA (PAFI-like) for and incentives for ing operations gage in aware- add fueling ca- industry R&D, testing, and aircraft owners to changes ness campaigns pacity; eased FAA certification incur expense certification 131 continued
From page 132...
... Main sources of Variability in Potential to af- Refiner capacity to Feasibility of Ability to design Potential to meet Rate of innovauncertainty in airport-specific fect practices meet tighter lead adding fuel sup- suitable engines fuel performance tion, certification achieving effective factors specifications ply chain (refiners for all high- requirements challenge, cost, and implementation and airports) ; performance owner interest certification aircraft Ancillary benefits Greater lead Greater lead Environmental Changes in poland concerns awareness and awareness and and health impacts lutants, including interest in lead- interest in lead- related to other greenhouse gases free fuels and free fuels and fuel components over life cycle propulsion propulsion NOTE: 100VLL = 100 octane very low lead aviation gasoline; FAA = Federal Aviation Administration; GA = general aviation; PAFI = Piston Aviation Fuels Initiative; R&D = research and development; UL = unleaded.
From page 133...
... . Airport lead air quality studies have shown that engine run-ups, whereby a pilot confirms shortly before takeoff that the engine is operating safely by briefly bringing the engine up to high power for system checks while the aircraft is stopped, can contribute to significant airborne lead concentrations at designated run-up areas.
From page 134...
... . Existing Fuels and Fleet While the downward trend in GA activity should yield gradual reductions in lead emissions from avgas consumption, larger reductions will require lowerlead or unleaded fuel alternatives to 100 octane low lead aviation gasoline (100LL)
From page 135...
... . FAA should research public policy options that will enable and encour age greater use of available unleaded avgas by the portion of the piston engine fleet that can safely use it.
From page 136...
... Although it has not yet yielded a viable replacement, PAFI has led to the development of a fuel testing and evaluation process, prompted supplier interest in developing replacement fuels, and sought solutions to the many regulatory, economic, and other practical challenges associated with developing, introducing, and broadly supplying an unleaded replacement fuel. FAA should continue to collaborate with the GA industry, aircraft us ers, airports, and fuel suppliers in the search for and deployment of an acceptable and universally usable unleaded replacement fuel.
From page 137...
... emissions from the production and use of transportation fuels may influence the availability and composition of petroleum-based aviation fuels and hasten the introduction of aviation propulsion systems that do not require petroleum. It will be important that the transition to using avgas with lower or no lead content also coordinates with efforts seeking to reduce or eliminate GHG emissions, given the shared concerns with developing and certifying new aircraft technology, the supply and distribution systems for GA aircraft fuels, and broad awareness within the GA community.
From page 138...
... Given the uncertainty of this development, CAA-specific regulatory tools were not considered in this study, but if they were to become available, they would almost certainly have a prominent role in a lead mitigation strategy. A key message of this report is that a lead mitigation strategy focused almost entirely on developing an unleaded drop-in fuel that would eliminate aviation lead emissions has a high degree of uncertainty of success given the formidable technical challenges.


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