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Options for Reducing Lead Emissions from Piston-Engine Aircraft (2021)

Chapter: 4 Changing Operations and Practices at Airports to Reduce Aviation Lead

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Suggested Citation:"4 Changing Operations and Practices at Airports to Reduce Aviation Lead." National Academies of Sciences, Engineering, and Medicine. 2021. Options for Reducing Lead Emissions from Piston-Engine Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/26050.
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Suggested Citation:"4 Changing Operations and Practices at Airports to Reduce Aviation Lead." National Academies of Sciences, Engineering, and Medicine. 2021. Options for Reducing Lead Emissions from Piston-Engine Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/26050.
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Suggested Citation:"4 Changing Operations and Practices at Airports to Reduce Aviation Lead." National Academies of Sciences, Engineering, and Medicine. 2021. Options for Reducing Lead Emissions from Piston-Engine Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/26050.
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Suggested Citation:"4 Changing Operations and Practices at Airports to Reduce Aviation Lead." National Academies of Sciences, Engineering, and Medicine. 2021. Options for Reducing Lead Emissions from Piston-Engine Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/26050.
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Suggested Citation:"4 Changing Operations and Practices at Airports to Reduce Aviation Lead." National Academies of Sciences, Engineering, and Medicine. 2021. Options for Reducing Lead Emissions from Piston-Engine Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/26050.
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Suggested Citation:"4 Changing Operations and Practices at Airports to Reduce Aviation Lead." National Academies of Sciences, Engineering, and Medicine. 2021. Options for Reducing Lead Emissions from Piston-Engine Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/26050.
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Suggested Citation:"4 Changing Operations and Practices at Airports to Reduce Aviation Lead." National Academies of Sciences, Engineering, and Medicine. 2021. Options for Reducing Lead Emissions from Piston-Engine Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/26050.
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Suggested Citation:"4 Changing Operations and Practices at Airports to Reduce Aviation Lead." National Academies of Sciences, Engineering, and Medicine. 2021. Options for Reducing Lead Emissions from Piston-Engine Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/26050.
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Suggested Citation:"4 Changing Operations and Practices at Airports to Reduce Aviation Lead." National Academies of Sciences, Engineering, and Medicine. 2021. Options for Reducing Lead Emissions from Piston-Engine Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/26050.
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Suggested Citation:"4 Changing Operations and Practices at Airports to Reduce Aviation Lead." National Academies of Sciences, Engineering, and Medicine. 2021. Options for Reducing Lead Emissions from Piston-Engine Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/26050.
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Suggested Citation:"4 Changing Operations and Practices at Airports to Reduce Aviation Lead." National Academies of Sciences, Engineering, and Medicine. 2021. Options for Reducing Lead Emissions from Piston-Engine Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/26050.
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Suggested Citation:"4 Changing Operations and Practices at Airports to Reduce Aviation Lead." National Academies of Sciences, Engineering, and Medicine. 2021. Options for Reducing Lead Emissions from Piston-Engine Aircraft. Washington, DC: The National Academies Press. doi: 10.17226/26050.
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PREPUBLICATION COPY – Uncorrected Proofs 59 4 Changing Operations and Practices at Airports to Reduce Aviation Lead Pilots and the employees of airports and airport tenants—particularly aircraft technicians and line service workers who refuel aircraft—may be exposed to lead contamination and be contributing to lead emissions to varying degrees from practices during the dispensing of leaded aviation gasoline (avgas), pre-flight fuel inspections and engine checks, and the maintenance and repair of piston-engine aircraft. This chapter examines these practices, what is known about their contribution to lead pollution and exposures, and options for changing them. Because piston- engine aircraft operate from a wide array of airports that can differ widely in characteristics such as traffic activity, the availability of on-site facilities and services, geographic and environmental settings, and airfield configurations, the importance of these sources of lead pollution and exposure will differ by airport. At the same time, because many options to influence these practices would not involve burdensome or costly interventions, even the promise of modest lead mitigation could favor their implementation. This chapter begins by identifying practices at airports that create lead emissions and exposures. Consideration is then given to steps that can be taken to change practices. Airports have long been the loci of similar efforts to mitigate concerns such as noise and wildlife hazards, often in partnership with the Federal Aviation Administration (FAA); other government agencies at the federal, state, and local levels; and the general aviation (GA) community. Like these other efforts, the recommendations in this chapter call for a multi-pronged and multi-partner approach to lead mitigation, and one that places a great deal of emphasis on ensuring that pilots, airport personnel, and airport service providers are well informed and aware of lead pollution risks and mitigation opportunities. CONTRIBUTORS TO LEAD EMISSIONS AND EXPOSURES AT AIRPORTS The U.S. Environmental Protection Agency (EPA) has noted that among the potentially largest sources of lead exposure at airports are the following activities (not in any particular order): • Aircraft fueling operations; • Pre-flight fuel sampling by pilots; • Aircraft maintenance and repair; and • Engine run-ups during pre-takeoff checks.1 Background on each of these contributors to lead emissions and exposures is provided in the following sections before considering options for reducing their contributions. 1 75 Federal Register 22440-22468. April 28, 2010. Advance Notice of Proposed Rulemaking on Lead Emissions from Piston-Engine Aircraft Using Leaded Aviation Gasoline; Proposed Rule. See https://www.govinfo.gov/content/pkg/FR-2010-04-28/pdf/2010-9603.pdf.

PREPUBLICATION COPY – Uncorrected Proofs 60 Fueling Operations As discussed in Chapter 2, fueling services at airports are usually provided by the airport operator or a tenant contractor, such as a fixed base operator (FBO), through either full-service or self-service dispensing. Self-service dispensing at unattended stations has become a popular option because it can lower avgas prices and save the pilot time and inconvenience by not having to wait for a mobile fueling truck or to refuel only during regular FBO operating hours. Indeed, at many airports that service piston-engine aircraft self-service is the only refueling option available. In cases where fueling services are not available, or if the pilot would rather not use the onsite fueling service, the pilot may self-fuel using avgas purchased off-site. The two basic methods of refueling are gravity-fed “over-the-wing” fueling and single entry point fueling using pressurized systems. Over-the-wing fueling—where the avgas is dispensed through ports on top of the wings—is the most common method for small piston- engine aircraft and for self-service operations generally. Avgas may also be delivered to the aircraft by mobile fueling trucks, especially when refueling through a single-entry point. Refueling trucks may obtain the avgas from an off-site fuel source, but more commonly from storage tanks located at the airport. A small airport may have a single tank for avgas storage with a capacity of 10,000 gallons or less, whereas an airport with more operations may have multiple tanks and a storage capacity of 100,000 gallons or more (NASEM, 2019). Whether the avgas is provided by full-service operators, through self-service stations, or by the pilot self-dispensing from a can, there is risk of exposure to lead from accidental overfilling, splashing, and spills onto the aircraft, ground, and body and clothes of the person doing the refueling. Exposures of fuel service personnel can also occur when loading and unloading avgas into and from the storage tanks. In its 2002 PBT National Action Plan for Alkyl-lead, EPA identified fuel service personnel, as well as pilots and aircraft technicians, as potentially being exposed to lead by inhaling vapor emitted during refueling, from spills, and from unused gasoline remaining in the engine or fuel tanks (EPA, 2002). The report also noted the potential for dermal absorption of lead from spilled avgas. However, EPA was not able to quantify the incidence and severity of these lead exposure sources. In implementing the Clean Air Act (CAA) and the Clean Water Act (CWA), EPA has established pollution control standards that apply to fuel evaporative emissions and spills but that include some exemptions for avgas. In the case of the CAA, the agency has established national emission limitations and management practices for hazardous air pollutants emitted during the loading of gasoline storage tanks and during its dispensing at fueling stations (40 CFR PART 63 SUBPART CCCCCC). Under these regulations, stations are required to install vapor recovery units to capture gasoline evaporative emissions. However, while the CAA standards apply to most facilities that dispense gasoline to end users (such as road users), they do not apply to storage and dispensing operations for avgas. The regulations state that “loading of aviation gasoline into storage tanks at airports, and the subsequent transfer of aviation gasoline within the airport” are not subject to requirements that establish national emission limitations and management practices for hazardous air pollutants (40 CFR PART 63 SUBPART CCCCCC). States may have their own regulations governing airport fuel dispensing and storage. Lead is also regulated as a toxic pollutant under the CWA. When avgas spills onto the aircraft parking surface, the lead in it can move in the environment in a number of ways as discussed in Chapter 3. EPA’s stormwater provisions under the CWA (National Pollutant Discharge Elimination System [NPDES] program) make it unlawful for industrial facilities to

PREPUBLICATION COPY – Uncorrected Proofs 61 discharge any pollutant from a point source into nearby water bodies or indirectly via storm sewer systems without a permit.2 Air transportation is a covered sector in the permitting program,3 and certain airport activities are specifically identified by EPA as potential sources of pollutant discharges, including deicing and anti-icing operations, fueling, and the servicing, repairing, and maintaining of aircraft. Common requirements for an industrial stormwater permit (usually administered by states under EPA delegation) include the development of a written stormwater pollution prevention plan and implementation of the planned prevention and control measures. Many smaller airports are covered under general NPDES permits, while some larger airports are more likely to have an activity-specific, individual permit because of the need to monitor and control runoff from chemical deicing operations (NASEM, 2016a). However, unlike these controlled deicing chemicals, lead is not likely to be the subject of similar pollutant- specific runoff controls by smaller airports that possess general NPDES permits only. In the case of FAA requirements pertaining to aircraft refueling, the agency’s regulations and guidelines, issued in various Advisory Circulars (ACs) and other publications, are safety- driven, intended mainly to prevent fire hazards. For instance, AC 150/5230-4B (FAA, 2012) requires airport fueling service providers and personnel to follow the codes and standards contained in the most recent edition of National Fire Prevention Association 407, “Standard for Aircraft Fuel Servicing Training Programs.” State and local regulations may also apply, and many individual airports will have their own requirements governing the training of fueling personnel; the siting, operation, maintenance, and inspection of fuel storage and dispensing systems; and the reporting of spills. It merits noting, however, that airports that receive federal aid from the Airport Improvement Program and that are part of the National Plan of Integrated Airport Systems (NPIAS) are required by grant assurances (obligations) to allow pilots to perform preventative maintenance on their aircraft, including self-fueling, without imposing unreasonable restrictions. Besides the federal government, individual states, local jurisdictions, and airport operators may have their own requirements that pertain to aircraft fueling hazards. In addition, even as they implement some of the CAA and the CWA requirements cited above, states will generally have their own set of environmental laws and regulations. Regarding fuel spills and evaporative emissions, these state and local requirements may be aviation-specific or loosely fall under other regulated industry sectors such as aboveground storage tanks or general environmental protection. Unfortunately, a state-by-state review of all applicable regulations that could apply to lead pollution at airports was not possible within the resources and scope of this study. The bottom line is that scant data are available on the frequency and magnitude of lead emissions and exposures from avgas evaporative emissions and spills from fueling operations at airports, in part because of the large number of airports, extensive self-fueling activity, and limited requirements by federal pollution control regulations for monitoring these emissions and discharges. However, even in the absence of information quantifying the extent to which fueling operations may contribute to lead pollution at airports, it is reasonable to assume such contributions are not always trivial and that any opportunities to mitigate them that are not 2 Per 40 CFR 302.4, the reportable quantity of spilled tetraethyl lead (TEL) is 10 pounds, which would require about 1,655 gallons of leaded avgas to be spilled assuming 2.74 grams of TEL per gallon. See https://www.govinfo.gov/content/pkg/CFR-2004-title40-vol26/pdf/CFR-2004-title40-vol26-sec302-4.pdf. 3 Multi-Sector General Permit for Stormwater Discharges Associated with Industrial Activity Sector S—Air Transportation Facilities.

PREPUBLICATION COPY – Uncorrected Proofs 62 especially costly or burdensome deserve consideration. Some examples of such opportunities are identified in the second half of this chapter. Pre-Flight Fuel Sampling As part of a typical aircraft pre-flight inspection, a pilot will strain, or sump, a small amount of avgas from the fuel system into a sampling receptacle and visually inspect it for contamination and condensation. The pilot may return the sample to the fuel tank if it appears to be uncontaminated or pour it into a container for safe disposal. Some pilots may discard the sampled fuel to the ground, a practice that is undesirable for the same reasons that spills from refueling are of concern. In this case, the discarded fuel can become a potential point source pollutant that will be discharged into the stormwater collection system and eventually to receiving water during the next precipitation event. A study on pilot fuel sampling and disposal practices was conducted by the FAA- sponsored Airport Cooperative Research Program (ACRP) in 2013 (TRB, 2014). Data on these practices were collected through an online survey of pilots asking them for details on their fuel sample disposal methods. Of the 146 pilots who responded to the survey, 36 percent indicated that they discard all samples to the ground regardless of visible contamination, while another 19 percent reported that they discard only contaminated samples to the ground and return uncontaminated samples to the tank. The remaining respondents reported that they either return the samples to the tank by using a fuel straining device (e.g., mesh screen) (26 percent), dispose of only the contaminated samples into a container (e.g., gas can or bucket) (4 percent), or dispose of all samples into such a container (16 percent). Based on these survey data, as well as FAA data on aircraft operations and assumptions about the share of inspected samples that are contaminated, the ACRP report authors estimated that between 75,000 gallons and 175,000 gallons of avgas are discarded to the ground annually following pre-flight fuel inspections. The applicability of this volume range today is unclear, because pilot behaviors may have changed since 2013, and because avgas consumption has continued to decline. The ACRP report also contains findings about airport practices for ensuring the safe disposal of inspected fuel. The researchers observed fuel sampling and disposal practices at three airports and consulted with a number of airport managers, FBOs, flight schools, and airport managers to identify procedures followed by pilots at different airports. While the researchers found that many airports provide fuel disposal containers, they also found evidence that the containers are not being used regularly. While the researchers observed a wide range of practices being employed when handling fuel samples, none of them could be linked to guidance from an industrywide consensus practice for how fuel sampling and disposal should be conducted. For instance, numerous pilot operating handbooks were reviewed for the ACRP study, and while many made reference to pre-flight fuel sampling, none explained how the pilot should manage the fuel sample once inspected. Based on these pilot surveys, observations of practice, and consultations with wide range of airport operators, the ACRP report was able to identify some potential best practices for reducing the frequency of pilots discarding fuel to the ground. These practices are discussed later in this report when considering opportunities for reducing the incidence of lead emissions and exposures from fuel spills, evaporate emissions, and inappropriate fuel disposal after pre-flight sampling.

PREPUBLICATION COPY – Uncorrected Proofs 63 Aircraft Maintenance Because a percentage of the lead in avgas is retained in the aircraft engine and engine oil, aircraft owners and technicians can be exposed to lead deposits and residue when performing scheduled aircraft maintenance and repairs. A health hazard evaluation report issued by the National Institute for Occupational Health and Safety pointed to the removal and cleaning of spark plugs as a potentially significant source of lead exposure (Chen and Eisenberg, 2013). Lead bromide deposits are created in the combustion chamber by the reaction of tetraethyl lead and the scavenging agent ethylene dibromide. As a result, the electrodes of spark plugs will become fouled and need to be cleaned during scheduled maintenance or sooner by aircraft technicians. Other engine parts, including cylinders, will also be contaminated and they too may be handled, and indeed sometimes washed in leaded avgas, by technicians during aircraft servicing and repair. Fouled spark plugs are typically cleaned by technicians in the shop using methods involving vibration and abrasive blasting. Some of the lead bromide that is agitated free from the electrode becomes fine lead dust and suspended in the air. By taking surface and air samples at observed shops, researchers have documented the presence of lead dust in the air, on shop surfaces, and on worker clothing (Beers, 2003). Some of the aircraft technicians who were observed during this research performed the cleaning unaware that the deposits being removed contained toxic lead, and they worked without the use of personal protective equipment, such as respirators or aprons. In the shops observed, no provisions were made for the technicians to shower and change clothing before they go home to potentially expose family members to lead dust. While Occupational Safety and Health Administration (OSHA) standards establish minimum requirements for compliance when a lead exposure hazard exists in a workplace (CFR 1910.1025), Beers (2003) noted that a review of federal regulations and government publications did not yield any prescribed process for the safe cleaning of aircraft spark plugs, nor any guidance on personal protective equipment or the avoidance of take-home exposures. Given the large number of piston-engine aircraft in the GA fleet (~170,000) and the adherence of many of their owners to an annual preventive maintenance schedule that usually includes examining, cleaning, and gapping spark plugs implies that aircraft technicians and owners, in the aggregate, are performing thousands of spark plug cleanings per year in which lead exposures are potentially taking place. Although the exposures from these procedures have not been quantified, they would appear to be a candidate for more targeted actions to ensure that aircraft owners and maintenance workers are aware of and protected from the hazards. Some potential opportunities for doing so are identified later in the chapter. Engine Run-Ups The practice of “running up” the aircraft engine when stopped prior to takeoff is noted in Chapter 2. A pilot is expected to operate the aircraft in accordance with its FAA-approved Pilot Operating Handbook or Aircraft Flight Manual in which the run-up procedures are specified. Typically, pilots will perform an engine check by advancing the throttle(s) to high RPM, at about two-thirds the RPM required for takeoff, to verify that the engine appears capable of producing takeoff thrust. Most pilots perform an engine run-up each time they operate an aircraft to ensure operational readiness. In cases where an aircraft is flown several times a day, such as during pilot

PREPUBLICATION COPY – Uncorrected Proofs 64 training, this practice may result in multiple engine run-ups by the same aircraft during the course of the day. A key part of the engine run-up is a magneto (and alternator/charging) test, which is performed while stopped at a throttle setting that produces a moderately high fuel consumption rate; whereas other pre-takeoff checks will occur at engine idle with much lower fuel flow. While magneto tests are typically on the order of one minute in duration, ACRP researchers observing operations found a large variation in these test times when, including some magneto tests that were much longer than the average (NASEM, 2015). In addition, engine run-ups are performed following engine repair or maintenance in order confirm post-repair operability. The duration of these run-ups was found by the ACRP researchers to be highly variable because of their situational nature (NASEM, 2015). Many airports have specific areas where pre-takeoff engine run-ups usually take place, either by designation or where they are commonly practiced by pilots. The area is frequently near the runway end or alongside the taxiway, usually in the close proximity to where takeoff will occur. The run-up area may be located where noise and air blast from engine or propeller wash do not create problems for other aircraft, structures, or ground traffic. In the case of maintenance run-ups, they may be performed near the repair facility or FBO. The only guidance that is provided relevant to the pre-takeoff or maintenance run-up location in FAA’s Airplane Flying Handbook is that the engine check should be performed on a firm surface (e.g., smooth, paved, or turf surface if possible) to minimize the potential for damage to the propeller from debris and in a windward direction to reduce the potential for engine overheating (FAA, 2016). Airport lead air quality studies conducted by EPA and ACRP have shown that pre-flight run-ups contribute a significant, if not predominant, share of ambient peak lead concentrations at airports (EPA, 2010; NASEM, 2015). ACRP evaluated lead emission sources and concentrations at three airports in detail, as noted earlier in Chapter 3. The researchers found run-up area activities (magneto test plus engine idle time) to be the source of 16 percent of total airport emissions on average for the three facilities studied, with 24 percent produced by the magneto test and 76 percent produced during engine idle time (NASEM, 2015). The researchers also found that the plume of emissions from run-up operations can combine with emissions plumes from other operations, especially takeoffs, when occurring near one another. In the next section, consideration is given to options for reducing lead emissions from engine run-ups and for controlling lead concentrations in proximity to run-up areas. These options include potential relocation of run-up areas to increase the distance between these checks and takeoff operations (thereby reducing the probability of overlapping plumes), the use of multiple run-up locations to serve the busiest runway (to redistribute run-up emissions), and increasing the size of the run-up area to serve multiple airplanes (to increase the surface area over which the emissions occur, potentially minimizing unnecessary idling that may otherwise occur due to traffic congestion). By and large, the cited ACRP reports provide the basis for the discussion of these options. OPPORTUNITIES TO REDUCE LEAD EMISSIONS AND EXPOSURES Each of the practices and activities discussed above presents opportunities to reduce lead emissions and exposures at airports through means such as increased education, training, and awareness of pilots, airport managers, and aircraft maintenance personnel; changes in airport environmental planning and policy guidance; and research to obtain a better understanding of

PREPUBLICATION COPY – Uncorrected Proofs 65 how airport activities are contributing to lead emissions and exposures and to identify best practices for reducing those contributions. Examples of opportunities are given next. Pilot and Airport Personnel Awareness, Education, and Training There is evidence, as discussed above, that many pilots and airport personnel may not fully appreciate the extent to which their own actions and behaviors are contributing to lead emissions and exposures, including their own exposure. Aircraft technicians and pilots performing repairs and maintenance may be exposed unknowingly to lead deposited on aircraft components, including spark plugs and other engine parts. Lead residue and dust can concentrate in shops where maintenance is performed, exposing the technicians to lead and potentially their families as a result of lead deposits brought home on clothing. Pilots and line personnel may be exposed to evaporative emissions that are not captured during refueling and when fuel is spilled or improperly discarded after sampling. Finally, when conducting their pre-takeoff checks, pilots may not fully appreciate how their decisions about where and how long to perform these operations can affect concentrations of lead at airports. This study could not assess the full extent to which existing government authorities and regulations could be better targeted to reduce these airport-related sources of lead emission and exposures, such as EPA’s authority to regulate evaporative emissions during fuel dispensing and storage. Nevertheless, there may be opportunities for EPA to draw more attention to lead emissions and discharges at airports. For example, in its list of best management practices for “good housekeeping” by airports to control spills and leaks during aircraft refueling, the agency could identify specific management practices for reducing lead pollution specifically (EPA, 2006). Such practices might include airports reminding pilots that topping off can lead to fuel spills and providing fuel waste containers at strategic locations and ensuring that these containers are regularly emptied. To be sure, any concerted effort to improve airport lead management practices would need to include efforts aimed at ensuring that pilots and airport personnel have greater awareness of how their activities and practices can contribute to lead pollution and how that pollution can be harmful to their own health and that of others. However, a review by this committee of the following FAA-issued documents pertaining to aircraft operations, flight training, airport management, and aircraft maintenance protocols, methods, and standards found no mention of lead emissions and exposures as an environmental risk or health hazard: • Airplane Flying Handbook, 2004 (FAA, 2004); • Airplane Flying Handbook, 2016 (FAA, 2020); • Airport Compliance Manual, 2009 (FAA, 2009); • Aviation Emissions and Air Quality Handbook, 2015 (FAA, 2015); • Aviation Instructor’s Handbook, 2020 (FAA, 2020); • Aviation Maintenance Technician Handbook, 2018 (FAA, 2020); • Aviation Maintenance Technician Handbook—Powerplant, 2018 (FAA, 2020); and • Pilot’s Handbook of Aeronautical Knowledge, 2016 (FAA, 2020). These handbooks and manuals, which are intended to have broad reach to GA pilots, aircraft technicians, and airport managers and line personnel, would therefore seem to be prime candidates for the inclusion of awareness and educational information on lead sources and risks

PREPUBLICATION COPY – Uncorrected Proofs 66 and on practical means for reducing them. One such opportunity is the ground operations chapter of the Airplane Flying Handbook, 2004 (FAA, 2004), which is developed to assist student pilots learning to fly as well as to improve the flying proficiency and aeronautical knowledge of experienced pilots. Chapter 2 of the handbook discusses pre-flight checks and assessment procedures. If an update of this handbook is planned, FAA could alert pilots to sources of lead emissions and exposures during ground activities such as self-service refueling, fuel inspection, and engine run-ups. The chapter could also contain guidance on best practices for ensuring fuel is not spilled and that inspected fuel is properly discarded. Likewise, the Pilot’s Handbook of Aeronautical Knowledge, 2016 (FAA, 2020), which is intended to be a reference for pilots as they progress through pilot training, could include similar information that emphasizes lead mitigation as one element of the basic knowledge important for piloting GA aircraft. To ensure that the next generation of pilots is similarly informed and develops good habits, the Aviation Instructor’s Handbook, 2020 (FAA, 2020) could emphasize such best practices, providing an early opportunity to instill airport environmental awareness in student pilots. Pilot training curricula could include instructions for ensuring that new pilots understand the environmental implications of aviation (including those of lead emissions) and are knowledgeable about best practices for activities such as fuel sampling, responsible engine run-up (i.e., how to choose safe locations and the amount of time needed to perform the check), and the desirability of using unleaded fuel where available and compatible with the aircraft. Both the general Aviation Maintenance Technician Handbook, 2018 and Aviation Maintenance Technician Handbook—Powerplant, 2018 (FAA, 2020) are FAA guidance documents specifically for aircraft mechanics and technicians. Both volumes of the latter handbook (on engines and exhaust systems) discuss lead fouling of spark plugs, but do not alert technicians to the risks they may face from lead exposures, nor do they refer to any safety or protective measures. Updates or supplements to these volumes would likewise present FAA with an opportunity to ensure that aircraft mechanics and technicians are aware of these risks and possible mitigation techniques to reduce personal exposure. Advice contained in Chen and Eisenberg (2013) could be consider to inform such an update—for instance, by reference to the document’s recommendations on the use of respirators during sandblasting of spark plugs, keeping children out of work areas, washing hands thoroughly before eating and drinking and before leaving the workplace, leaving work clothes at the workplace, and wearing disposable shoe covers when working. FAA issues many other handbooks, manuals, and guidance documents that are even more specific to segments of the GA community, including operators of ultra-light, amateur-built, and rotary-wing aircraft (FAA, 2020). These documents also may provide opportunities to alert and educate aviators and technicians to the aviation lead problem and to identify possible mitigation measures. Similar opportunities exist to provide airport operators and managers with more information on lead risks and practices for reducing them. For instance, the Airport Compliance Manual, 2009 (FAA, 2009) contains guidance on airport operator responsibilities for the operation and maintenance of airports that receive federal grants. FAA’s latitude to amend this manual to include guidance on best practices for reducing lead emissions and exposures is unclear. Nevertheless, to the extent that latitude exists, the manual could be a place to prompt airport operators to follow best practices, such as for designating appropriate locations for engine run-ups and for advising pilots and airport personnel about relevant operational procedures for avoiding fuel spills and managing inspected fuel samples. The previously discussed ACRP report

PREPUBLICATION COPY – Uncorrected Proofs 67 on Best Practices for General Aviation Aircraft Fuel-Tank Sampling identifies several such practices that could potentially be incorporated into this guidance (TRB, 2014). FAA’s Aviation Emissions and Air Quality Handbook, 2015 (FAA, 2015) is intended to assist airports with the planning and completion of air quality assessments conducted for aviation-related projects and operations. Lead is identified as one of the six criteria pollutants regulated under the CAA. The handbook points to EPA methods for calculating lead emissions from piston-engine aircraft operations. The information in this handbook could therefore be expanded to assist airport operators in modeling and calculating lead emissions from other airport sources, such as from engine run-up, refueling, and aircraft maintenance. Similar information might also be included in the Airport Compliance Manual, 2009 (FAA, 2009). While a more explicit and detailed treatment of lead emissions and exposure sources and risks in such FAA handbooks, manuals, and other guidance documents would seem to be an essential first step in a general campaign to make airport personnel and aviators more attuned to the lead problem and aware of best practices for managing it, such a campaign would need to capitalize on the other collaborative opportunities to expand awareness across the GA community. In particular, FAA’s longstanding partnerships with organizations representing airports, aircraft manufacturers, pilots, flight instructors, and aviation educational institutions could be leveraged, such as by coordinating with the General Aviation Manufacturers Association (GAMA), the Aircraft Owners and Pilots Association (AOPA), the Experimental Aircraft Association (EAA), the National Air Transportation Association (NATA), the American Association of Airport Executives (AAAE), the Small Aircraft Manufacturers Association (SAMA), the National Association of Flight Instructors (NAFI), the Society of Aviation and Flight Educators (SAFE), and the Professional Aviation Maintenance Association. FAA has a long-standing history of collaborating with these GA organizations on initiatives such as noise abatement, flight safety, wildlife hazard mitigation, and the development of lead-free fuels. Ensuring that lead awareness information and educational materials are provided in the handbooks, guides, and curricula materials of these organizations could be a key element of a more comprehensive campaign, which could also include special exhibits at GA events. It is notable, for instance, that FAA is a regular exhibitor at the EAA AirVenture Oshkosh and Sun’n Fun Kissimmee fly-ins, where it has sponsored related exhibits on the Piston Aviation Fuel Initiative. Thousands of GA pilots participate in these and other fly-ins (such as AOPA regional fly-ins), which could provide broader awareness among aviators about lead problems and potential mitigation efforts. These are just a few examples of the wide array of aviation industry and enthusiast trade shows, conferences, and other forums that could be tapped by such an awareness campaign if sponsored by FAA in partnership with the GA community. Working with FAA, aviation associations and their members could have direct roles in disseminating information on appropriate best practices though a variety of other means such as newsletters, webinars, website guidance, and modifications to important documents such as the pilot and operator handbooks issued by aircraft manufacturers. There are numerous models for such awareness campaigns, including the “Know Before You Fly” education campaign to promote awareness by aviators of drones (AUVSI, 2020).

PREPUBLICATION COPY – Uncorrected Proofs 68 Airport Planning and Environmental Policy Guidance FAA has oversight and regulatory authority for those airports that receive federal aid and that are included in the NPIAS. In 2013, the Office of Airport Planning and Environmental Division issued the following interim guidance to airports on mitigating public risks associated with lead emissions from pre-takeoff run-ups (FAA, 2013). • If existing run-up areas typically cause propeller wash to be directed off airport property or into areas where the general public can be exposed, the airport operator should consider shifting either the location or orientation of run-up activities to locations where the emissions can be better contained to non-public areas of the airport. • In cases where it is not immediately feasible to reduce lead emissions, consider minimizing the public’s outdoor air exposure to lead emissions by either shifting fences (to increase the distance between run-up areas and public observation areas) and/or posting signs to discourage loitering by the public in those areas where there may be potential and unnecessary exposure to lead from piston-engine aircraft emissions. This FAA guidance, which was characterized as “interim,” has not been updated since it was issued in 2013. The guidance points to the importance of shifting the location or orientation of run-up activities to locations where emissions can be contained to non-public areas; however, it is silent about whether airports should consider moving their run-up locations away from runway ends that have high volumes of aircraft taking off. As discussed in Chapter 3, ACRP examined the option of relocating run-up areas or redistributing the use of existing run-up areas in order increase the dispersion of emissions and reduce peak ambient lead concentrations (NASEM, 2016b). To see if changes in run-up areas would reduce the magnitude of these lead hot spots, the ACRP research team modeled emissions at three airports where run-up areas were relocated and dispersed away from the runways ends. Runway ends were determined to be hot spots for lead concentrations because the emissions from run-ups will mix with the emissions from aircraft taking off. The results of the ACRP study, issued 3 years after FAA’s interim guidance, suggest that it may be time to update the guidance, in particular to address the desirability of moving run-up areas away from runway ends to other locations as long as they do not expose the general public to emissions or present other concerns such as degraded safety or excessive noise. FINDINGS AND RECOMMENDATIONS A review of FAA-related manuals and handbooks pertaining to flight training, aircraft maintenance, and airport management found scarce mention of lead emissions and exposures as an environmental risk or health hazard nor guidelines for refueling to avoid spills and emissions, ensuring the safe disposal of inspected fuel, and reducing exposures to lead deposits when performing aircraft maintenance and repairs (Finding 4.1). FAA should coordinate its efforts to reduce lead pollution and exposures at airports with those of other federal agencies that have key responsibilities for protecting public health,

PREPUBLICATION COPY – Uncorrected Proofs 69 safety, and the environment at airports, including the Occupational Safety and Health Administration (OSHA) as well as EPA. FAA should collaborate with these agencies to explore the regulatory and programmatic means within their respective jurisdictions that can be brought to bear and combined in a complementary manner to reduce lead emissions and exposures at airports (Recommendation 4.1). FAA, in partnership with prominent organizations within the GA community, should initiate an ongoing campaign for education, training, and awareness of avgas lead exposure that is targeted to GA pilots, aircraft technicians, and others who work at airports. Informed by research on the most effective approaches for reaching these audiences, the campaign should be multi-pronged by ensuring that information on lead risks and mitigation practices is prominent in relevant manuals, guidelines, training materials, and handbooks for pilots, airport management, and aircraft technicians. Where appropriate, it should also be covered in relevant certification and licensure examinations. In addition, the information should be featured on FAA and GA organization websites and included in written materials distributed at GA industry conferences, tradeshows, and fly-ins (Recommendation 4.2). 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 full power for system checks while the aircraft is stopped, can contribute to significant airborne lead concentrations at designated run-up areas. Aircraft maintenance personnel may also perform extensive engine tests at run-up areas. Run-up area planning guidance provided by FAA has not been updated to reflect the results of air quality studies that suggest it may be desirable for airports to move their run-up locations away from being close to where human activities occur (including activities both on-airport and in neighboring communities) and away from high-traffic locations such as runway ends where lead is also emitted from aircraft taking off (Finding 4.2). FAA should update its guidance on the location of run-up areas to reflect the results of research since the latest interim guidance was issued in 2013, including the need to account for both the emissions of engine run-ups and of takeoffs when analyzing the geographic distribution of lead emissions at the airport. This analysis should support decisions of whether to move run-up areas to reduce people’s exposure to lead emissions while also accounting for other concerns including safety and aircraft noise (Recommendation 4.3). REFERENCES AUVSI (Association for Unmanned Vehicle Systems International). 2020. Know Before You Fly. Available at: http://knowbeforeyoufly.org/about-us. Beers, C.E. 2003. Controlling Lead Exposure During the Process of Cleaning Aviation Spark Plugs. Dissertations and theses. Available at: https://commons.erau.edu/cgi/viewcontent.cgi?article=1002&context=edt. Chen, L., and J. Eisenberg. 2013. Health hazard evaluation program: Exposures to lead and other metals at an aircraft repair and flight school facility. NIOSH Report No. 2012-0115- 3186. Cincinnati, OH, U.S. Department of Health and Human Services, Centers for

PREPUBLICATION COPY – Uncorrected Proofs 70 Disease Control and Prevention. Available at: http://www.cdc.gov/niosh/hhe/reports/pdfs/2012-0115-3186.pdf. EPA (U.S. Environmental Protection Agency). 2002. PBT National Action Plan for Alkyl-lead. June. Available at: http://www.reidhillview.com/EPA_Alkyl_lead_action_plan_final.pdf. EPA. 2006. Sector S: Vehicle Maintenance Areas, Equipment Cleaning Areas, or Deicing Areas Located at Air Transportation Facilities. Industrial Stormwater Fact Sheet Series, U.S. EPA Office of Water EPA-833-F-06-034 December. Available at: https://www3.epa.gov/npdes/pubs/sector_s_airtransmaint.pdf. EPA. 2010. Development and Evaluation of an Air Quality Modeling Approach for Lead Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline. EPA- 420-R-10-007, prepared by ICF International and T&B Systems. FAA (Federal Aviation Administration). 2004. Airplane Flying Handbook 2004. FAA-H-8083- 3A. Available at: http://large.stanford.edu/courses/2013/ph240/eller1/docs/FAA-H-8083- 3B.pdf. FAA. 2009. Airport Compliance Manual 2009. Available at: https://www.faa.gov/airports/resources/publications/orders/compliance_5190_6. FAA. 2012. Aircraft Fuel Storage, Handling, Training, and Dispensing on Airports. 150/5230- 4B. Available at: https://www.faa.gov/airports/resources/advisory_circulars/index.cfm/go/document.curren t/documentNumber/150_5230-4. FAA. 2013. Interim Guidance on Mitigating Public Risks Associated With Lead Emissions from Avgas. Memorandum dated June 19. Available at: https://www.faa.gov/airports/environmental/policy_guidance/media/leadMitigationMemo June2013.pdf. FAA. 2015. Aviation Emissions and Air Quality Handbook 2015. Available at: https://www.faa.gov/regulations_policies/policy_guidance/envir_policy/airquality_handb ook. FAA. 2016. Airplane Flying Handbook. FAA-H-8083-3B. Available at: https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/airplane_handboo k. FAA. 2020. Aviation Handbooks and Manuals. Available at: https://www.faa.gov/regulations_policies/handbooks_manuals/aviation. NASEM (National Academies of Sciences, Engineering, and Medicine). 2015. Quantifying Aircraft Lead Emissions at Airports. Washington, DC: The National Academies Press. https://doi.org/10.17226/22142. NASEM. 2016a. Clean Water Act Requirements for Airports. Washington, DC: The National Academies Press. https://doi.org/10.17226/24657. NASEM. 2016b. Guidebook for Assessing Airport Lead Impacts. Washington, DC: The National Academies Press. https://doi.org/10.17226/23625. NASEM. 2019. Airport Management Guide for Providing Aircraft Fueling Services. Washington, DC: The National Academies Press. https://doi.org/10.17226/25400. TRB. 2014. Best Practices for General Aviation Aircraft Fuel-Tank Sampling. Washington, DC: The National Academies Press. https://doi.org/10.17226/22343.

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Small gasoline-powered aircraft are the single largest emitter of lead in the United States, as other major emission sources such as automobile gasoline have been previously addressed. A highly toxic substance that can result in an array of negative health effects in humans, lead is added to aviation gasoline to meet the performance and safety requirements of a sizable portion of the country’s gasoline-powered aircraft.

Significantly reducing lead emissions from gasoline-powered aircraft will require the leadership and strategic guidance of the Federal Aviation Administration (FAA) and a broad-based and sustained commitment by other government agencies and the nation’s pilots, airport managers, aviation fuel and service suppliers, and aircraft manufacturers, according to a congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine.

While efforts are underway to develop an unleaded aviation fuel that can be used by the entire gasoline-powered fleet, the uncertainty of success means that other steps should also be taken to begin reducing lead emissions and exposures, notes the report, titled TRB Special Report 336: Options for Reducing Lead Emissions from Piston-Engine Aircraft.

Piston-engine aircraft are critical to performing general aviation (GA) functions like aerial observation, medical airlift, pilot training, and business transport. Other GA functions, such as crop dusting, aerial firefighting, search and rescue, and air taxi service, have particular significance to communities in rural and remote locations.

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