In order to be certified and approved for use, engines currently in production with a maximum take-off thrust of over 26.7 kN must comply with certain emission limits, as is the case with car engines. In aviation, emission standards are set by the International Civil Aviation Organization (ICAO). These standards have been limiting gaseous pollutants and visible smoke for over 30 years. The first emission criteria for particulate matter will soon be introduced, which all engine types manufactured after 1 January 2020 must meet.
For emission certification, engine manufacturers use almost brand-new engines, selected based on their individual performance. However, the emission values obtained and entered into the ICAO engine emissions databank do not necessarily reflect the actual pollutants emitted in operation. Among other things, wear processes in ageing engines are not taken into account. This is important because the ICAO engine emissions databank serves as a basis for studies that investigate the impact of aviation emissions on the environment, air quality and thus, health.
The Meteorology, Environment and Aviation group at the Centre for Aviation (ZAV in ZHAW) deals with the measurement and modelling of engine emissions. In the AGEAIR project, financed by the Federal Office of Civil Aviation (FOCA), emissions from engines requiring maintenance are measured at Zurich Airport in collaboration with SR Technics. In order to be able to reassemble the engines on an aircraft after maintenance, they must first be put through their paces. During these tests, we would use the "SMARTEMIS“ measurement infrastructure to carry out emission measurements with a permanently installed and retractable probe so that operation in the test cell at SR-Technics is not disturbed.
In the course of 2019 and 2020, emissions from engines with different operating hours will be measured and scientifically evaluated. In addition, the results will be used in scientific publications and possibly applied in recommendations of correction factors for the ICAO engine emissions databank depending on the pollutant and operating hours of the tested engines.