Swedish Defence

Research Agency


The Environmental Impact of Aircraf

Reducing the environmental impact of aircraft often involves complex trade-offs between different environmental actions. The purpose of FOI’s work is to develop system analysis tools and methods with which to model the aircraft’s environmental impact so the total effect of changes and remedial measures can be assessed. This creates an analysis capability which authorities and other actors in the aircraft sector can make use of in their evaluation of military and civil aircraft systems.

FOI possesses a broad knowledge base relating to the impact of aircraft on the environment. We have access to tools for the calculation of emissions and are able to provide results that take account of how the aircraft is being operated, climatic effects and the existing laws and regulations governing environmental and climatic reporting.

FOI:s Confidential database for Turboprop Engine Emissions

FOI is the keeper of a confidential database of emission indices (EI) of NOX, HC and CO with corresponding fuel flows for turboprop engines. The turboprop engine manufacturers have supplied Datasheets, originally for the purposes of calculating emissions-related landing charges.

To obtain the turboprop emissions database, please send an e-mail to and describe the purpose of use of the database. The database can be distributed on certain conditions and after ICCAIA’s concurrence.

Emissions data for piston-powered aircraft can be found at the Swiss Federal Office of Civil Aviation (FOCA).

The data are presented in the same format as the ICAO (International Civil Aviation Organization) Engine Emissions Database for jet engines, but have not been endorsed by ICAO in a certification process. It should be noted that the data have many inaccuracies resulting primarily from the unregulated test methodologies. The data is however considered as being the best available and may be used for emissions inventories, emissions-related landing charges etc.

There is also a significant issue of an appropriate idle setting for turboprops, see International Coordinating Council of Aero­space Industries Associations recommen­dations and the FOI study “Methodology for establishing the relation between thrust and power for propeller equipped engines”  (FOI-R—0855—SE, October 2003) .

Suggested Times in Mode (TIM) for calculating LTO emissions for turboprops.


Time (Min.)



Climb out






*26 minutes for larger airports (corresponding to ICAO’s emission certification time) and 13 min for small/regional airports if actual taxi times are not known.

FOI undertakes studies and develops computational methods for sound generation and propagation. Noise is the form of environmental disturbance that affects the Swedish population the most, even though it does not directly threaten human survival or that of other organisms. Compared with traffic noise, for example, aircraft noise affects a significantly smaller proportion of the population. However, aircraft noise is often perceived as a greater nuisance, despite comparable sound levels.

Both civil and military aircraft are subject to regulation, enforced through monitoring of compliance to fixed noise level guidelines and requirements. Even though technological improvement continuously reduces the noise levels produced by new generations of aircraft, the problem has not diminished in significance. The increasing density of built areas surrounding airports and the steadily growing volume of air traffic may explain this trend.

FOI has experience in performing studies of sound generation, for example the sound generated by airflow around a wing or undercarriage, and its associated mechanisms, and in developing the relevant computational tools. Our computational tools are often general, for they are also applicable to other noise than that generated by aircraft.

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FOI – Research for a safer and more secure world.

FOI’s core activities are research, methodology/technology development, analyses and studies.

FOI is an assignment-based authority under the Ministry of Defence.

FOI’s core activities are research, methodology/technology development, analyses and studies. FOI is an assignment-based authority under the Ministry of Defence.