Quantifying Aircraft Lead Emissions at Airports (2015) / Chapter Skim
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From page 10... ...
3. REVIEW OF EXISTING METHODS FOR QUANTIFYING AIRCRAFT-RELATED LEAD EMISSIONS In its simplest form, the methodology for quantifying lead emissions from an individual aircraft during a given airport operation (e.g., taxiing)
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From page 11... ...
Furthermore, to the extent that one seeks to use aircraft-related Pb emissions data in combination with air quality models to estimate ambient Pb concentrations at points in and around the airport, information is also needed regarding spatial and temporal patterns of aircraft activity as well as relevant meteorological data. Because of the scope and complexity of the information needed to quantify aircraftrelated lead emissions for a given airport and the resources required to obtain that information, many simplifying assumptions are typically required.
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From page 12... ...
Table 3 Original Fuel Flow Rates from AP-42 Engine Model Fuel Flow Rate per Mode of Operation (lb/hr) Taxi/Idle Takeoff Climb-out Approach Continental O-200 7.68 48.4 48.4 21.3 Lycoming O-320 13.0 65.7 63.5 23.1 Source: U.S.
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From page 13... ...
Table 4 Updated Fuel Flow Rates from AP-42 Engine Model Fuel Flow Rate per Mode of Operation (lb/hr) Taxi/Idle Takeoff Climb-out Approach Continental O-200 8.4 45.0 45.0 25.8 Continental TSIO-360C 11.4 133.2 99.6 61.2 Lycoming O-320 9.6 88.8 66.6 46.8 Source: U.S.
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From page 14... ...
Table 5 EDMS Fuel Flow Rates Engine Model Fuel Flow Rates by Mode of Operation (lb/hr) Taxi/Idle Takeoff Climb-out Approach Continental 6-285-B 72.1 153.0 166.0 83.3 Continental IO-360-B 8.1 103.0 71.7 36.6 Continental O-200 8.3 45.2 45.2 25.5 Continental TSIO-360C 11.5 133.3 99.2 61.0 Lycoming IO-320-D1AD 7.8 91.7 61.4 37.6 Lycoming O-320 9.4 88.9 66.7 46.5 Lycoming TIO-540-J2B2 25.0 259.7 204.5 99.2 Wright R-1820 88.9 1165.9 861.9 323.0 Source: Federal Aviation Administration Emissions and Dispersion Modeling System (version 5.0.2)
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From page 15... ...
LTO cycle during the cruise mode of operation, apportioned to individual states based on their share of the national general aviation and air taxi LTOs used in the NEI. The NEI documentation acknowledges that its methodology would benefit from the following improvements (ERG 2011)
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From page 16... ...
consumption during landing based on the assumption that engines would operate at full load. Run-up fuel consumption rates were obtained from operational manuals for the IO-360, IO-320, GSO-480, IO-550, TIO-540-J2B2, and TSIO-550 engines.
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Table 6 Swiss FOCA Fuel Flow Rates Engine Model Horsepower (HP) Fuel Flow Rate per Mode of Operation (lb/hr)
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collected at varying engine power settings, many of which do not directly correspond to those assumed in the existing emissions inventory methodologies. Figure 4 shows the covariation of mass fuel flow (in lbs/hr)
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Figure 4 Covariation of BSFC with Mass Fuel Flow (Legend: Engine, Fuel, % Throttle)
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To address this issue, data regarding observed aircraft operations or data from provided airport records could be used in combination with the FAA's Tail Number Registry and Type Certification database to determine specific airframe types and engines in operation at an airport, to the extent tail number information is available for the facility. Alternatively, the FAA's TFMSC (previously the Enhanced Traffic Management System Counts, ETMSC)
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From page 21... ...
Additionally, although modal load factors are available for the more traditional modes of operation within the LTO cycle, factors for new modes (i.e., run-up/maintenance) , as well as refinements to existing modes (i.e., continuous lowering of load during approach and landing)
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From page 22... ...
As noted above, EPA's original methodology for calculating Pb emissions from piston aircraft within the NEI assumed that 25% of the Pb consumed by the engine was retained in the engine oil based on data from automobiles designed to operate on leaded fuel. More recently, Petersen (2008)
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Table 8 Time-in-Mode Comparison Facility Piston Aircraft Times in Mode (minutes)
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Overall, the data show considerable variation in TIM values, and TIM data collected at specific airports show that fleet mix, the local mixing height (which affects TIM for takeoffs and landings) , and taxi patterns can have a significant bearing on actual TIM values.
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concentrations at an airport is going to be performed -- to characterize temporal variations in those operations. For example, given that aircraft usage can vary by season, month, or day of the week, resolution of that variation will improve airport Pb emission inventories that are prepared for similar time frames.
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From page 26... ...
Figure 5 Model-to-Monitor Comparison at SMO 3.3.9 Proper Documentation A general finding throughout the literature search of existing emissions inventory methodologies, as well as airport-specific emissions inventories, was a lack of sufficient detail to allow emissions inventory results to be recreated. Inadequate documentation included, but was not limited to, the following: • Specification of operational data sources with inadequate detail on how they were accessed, used, and manipulated for the purposes of preparing an emissions inventory; • Specification of TIM with inadequate detail on how it was either empirically observed or calculated from obtained data; • Lack of detail on averaging methods and operational assumptions (i.e., load points, horsepower)
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From page 27... ...
Clearly, proper documentation of aircraft Pb inventories is important because it ensures reproducibility, which aids in validation, and helps identify potential sources of erroneous results that could be avoided by refining assumptions or adjusting the fidelity at which each inventory parameter is treated. In order to ensure that proper documentation is being provided, the technical issues outlined below need to be addressed in detail.
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