The National Academies

ACRP 02-54 [Final]

Measuring and Understanding Emission Factors for General Aviation (GA) Aircraft

  Project Data
Research Agency: Aerodyne Research, Inc
Principal Investigator: Tara Yacovitch
Effective Date: 5/20/2014
Completion Date: 6/30/2016

Airports, among others, use the FAA’s Emission and Dispersion Modeling System (EDMS) that is a tool to perform air quality analysis. Soon the FAA will replace the EDMS with Aviation Environmental Design Tool (AEDT). Both modeling systems utilize emission data for various aircraft engines but there is greater confidence in the data for larger commercial aircraft engines obtained in part from ICAO’s aircraft engine emissions databank. However, for smaller aircraft such as piston and small turbine-powered aircraft, emission factor data is either non-existent or hasn’t been independently verified. This could underestimate or overestimate aircraft emissions. Further, there is no standard methodology for obtaining the emissions data to determine factors for smaller aircraft engines. This uncertainty makes it difficult for airports with significant GA operations to characterize their emission inventories with the precision that larger airports are able to achieve due to the availability and confidence of data.

The objective of this research is to obtain aircraft emissions measurements that airports can use to better understand and estimate GA aircraft emissions. The measurements should be taken for each operational mode of aircraft activity for gaseous (HC, CO, and NOx) and PM emissions of piston and turbine aircraft (not included in the ICAO aircraft engine emissions databank) to develop more accurate GA aircraft emission factors that can be used in EDMS/AEDT or other emission databases to (1) verify sample data sets that exist, (2) supplement most commonly used aircraft engine data that doesn’t currently exist in EDMS/AEDT or other emission databases, and (3) develop recommendations for determining substitution for aircraft that aren’t currently in existing emission databases.
The research should include at a minimum:
  • Documentation of the methodology used to collect data;
  • Data in a format (emissions indices in g/kg) that can be readily implementable and consistent with EDMS/AEDT;
  • Comparison of the measured data with corresponding existing data;
  • A sensitivity analysis of a hypothetical airport(s) showing how the emission factors differ from the verification data findings and how those differences could impact an airport’s emission inventory based on varying number of operations and different aircraft fleet mix;
  • Recommendations for determining substitution aircraft for aircraft where there is no existing emission data; and
  • Discussion on the relevance of findings that airports can use to understand the outcomes of the research.

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