This appendix provides an overview of the data sources, models and assumptions used to develop the information presented in Chapter 1 (Overview of Aviation Sector), Chapter 2 (Technology and Design) and Chapter 6 (Airports). These modelling capabilities have been developed and used to support various European initiatives, including SESAR and Clean Sky, as well as international policy assessments in ICAO CAEP.
The information in this report covers all flights from or to airports in the European Union (EU) and European Free Trade Association (EFTA). For consistency, regardless of the year, the EU here consists of the current 27 member States: Austria, Belgium, Bulgaria, Croatia, Republic of Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain and Sweden. EFTA members are Iceland, Liechtenstein, Norway and Switzerland. Compared to previous reports, statistics for UK are therefore not included, also for the years preceding the Brexit.
The calculation of the Lden, Lnight and N50A70 noise indicators was performed over 98 major EU27+EFTA airports (see map on next page) representing about 90% of the total landing and take-off noise energy emitted in the region during 2019.
EUROCONTROL Flight Data
Historical 2005-2021 flight operations were extracted from the EUROCONTROL database of filed flight plans. This covers all instrument flight rules (IFR) flights in Europe. Flight data are enriched with and validated against, for example, radar updates, billing data from the Central Route Charges Office and an internal database of global aircraft. Each flight is categorised into one of the market segments: scheduled flights are divided into “low-cost” and “traditional scheduled”; “business aviation” captures flights by jets, turboprops and piston aircraft typically used for business aviation (mostly under 20 seats nominal size); “all-cargo” captures dedicated freighter flights; etc. These market segments are defined in terms of aircraft operator, aircraft type, ICAO flight type or callsign, as appropriate. The detailed definitions are available on the EUROCONTROL website.
European States collect statistics on air transport from their airports and airlines and provide these to Eurostat, which makes them public, although airline details are treated as confidential. Statistics on total activity (total passengers, total tonnes shipped, etc.) are as complete as possible. More detailed statistics, such as passengers and available seats for individual airport pairs, are focused on major flows. For example, we use these data to indicate trends in load factors, but we cannot calculate total available seat-kilometres solely from them. The estimates of total passenger kilometres flown in Chapter 1 are based on Eurostat directly, on analysis of other Eurostat flows and on data from PRISME. The great circle (i.e. shortest) distance between airport pairs is used when reporting passenger kilometres and calculating the average fuel consumption per passenger kilometre. The fuel consumption reported is however based on the actual distance flown. Consequently, the effect of ATM horizontal inefficiency is captured in the fuel efficiency indicator.
The EUROCONTROL Aviation Outlook 2050] that was published in April 2022 provided the traffic forecast to 2050 used in this report. It has three scenarios: the ‘high’ has strong economic growth with intense investment in technology to support sustainability, leading to relatively high growth in demand; the most- likely, ‘base’ scenario has moderate economic growth following current trends; the ‘low’ has slower economic growth and higher fuel prices, leading to fewer flights and lower investment. As is usual for STATFOR forecasts, airports provided their future capacity plans, and the forecast traffic respects the capacity constraints implied by these plans, although the EAO notes that increasingly the primary constraint is sustainability rather than capacity.
BADA (Base of Aircraft Data) is an Aircraft Performance Model developed and maintained by EUROCONTROL, in cooperation with aircraft manufacturers and operating airlines. BADA is based on a kinetic approach to aircraft performance modelling, which enables to accurately predict aircraft trajectories and the associated fuel consumption. BADA includes both model specifications which provide the theoretical fundamentals to calculate aircraft performance parameters, and the datasets containing aircraft-specific coefficients required to calculate their trajectories. The BADA 3 family is today’s industry standard for aircraft performance modelling in the nominal part of the flight envelope, and provides close to 100% coverage of aircraft types operating in the European region. The latest BADA 4 family provides increased levels of precision in aircraft performance parameters over the nearly entire flight envelope, and covers 80% of aircraft types operating in the European region. This report uses BADA 4, complemented by BADA 3 for aircraft types not yet covered in BADA 4.
Aircraft Noise and Performance (ANP) Database
The Aircraft Noise and Performance (ANP) database is maintained by EASA, EUROCONTROL and the US Department of Transportation. It provides the noise and performance characteristics for over 150 civil aircraft types, which are required to compute noise contours around civil airports using the calculation method described in Annex II of European Directive 2002/49/EC relating to assessment and management of environmental noise, ECAC Doc 29 and ICAO Doc 9911 guidance documents. ANP datasets are supplied by aircraft manufacturers for specific airframe-engine types, in accordance with specifications developed by the ICAO and European bodies. EASA is responsible for collecting, verifying and publishing ANP data for aircraft which fall under the scope of Regulation (EU) 598/2014.
EASA maintains a database of all aircraft noise certification levels which the Agency has approved. The database provides certified noise levels for over 34,000 aircraft variants, including jet, heavy and light propeller aircraft as well as helicopters. In this report, the certified noise levels are used to assess the Noise Energy Index, to attribute an ANP airframe-engine type to each aircraft type in the fleet using the ECAC Doc 29 4th Edition recommended substitution method, as well as to create the noise charts in the Technology and Design and Airport chapters.
The ICAO Aircraft Engine Emissions Databank (EEDB) hosted by EASA contains Landing and Take-Off (LTO) emissions data for NOx, HC, CO, smoke number and non-volatile PM for over 400 jet engine types. The EEDB emission indices are used by the IMPACT model to compute NOX, HC, CO and PM, and to create the NOX charts in the Technology and Design chapter.
The Swedish Defence Research Agency (FOI) hosts a database of NOx, HC and CO emission indices for turboprop engine types. The data was supplied by the turboprop engine manufacturers, originally for the purposes of calculating emissions-related landing charges. It is used to complement the ICAO EEDB for the NOx, HC and CO estimates in this report.
The Swiss Federal Office of Civil Aviation (FOCA) hosts a database of NOx, HC, CO and aggregated non- volatile and volatile Particles Matters emission indices for piston engine types. The data was measured and calculated by the FOCA. It is used to complement the ICAO EEDB for the NOX, HC, CO and PM estimates in this report.
CODA Taxi Times Database
EUROCONTROL’s Central Office for Delay Analysis (CODA) collects flight-by-flight data from around 100 airlines and 130 airports, such as actual off-block and take-off times, and delay causes. Largely this is on a voluntary basis in return for performance and benchmarking reports, but increasingly the data collection is influenced by the EU performance regulations. CODA publishes aggregated performance statistics, such as on punctuality and all-causes delays from these data. The detailed actual taxi times from this source were used to assess taxi fuel burn and emissions.
The JRC Global Human Settlement population grid was used to calculate the number of people exposed to aircraft noise. This spatial dataset, developed in the European Copernicus Program, depicts the distribution and density of residential population. The dataset is generated using the 2011 censuses provided by Eurostat/GEOSTAT and the best available sources by country. The initial 1 km resolution has been further disaggregated to 100 m based on information from Corine Land Cover Refined 2006 and the European Settlement Map 2016.
Models and methods
IMPACT is a web-based modelling platform developed and hosted by EUROCONTROL to assess the environmental impacts of aviation (noise and emissions). It allows to compute full-flight trajectories with associated fuel burn and CO2 emissions thanks to an advanced aircraft performance-based trajectory model using a combination of ANP and BADA reference data. Other gaseous emissions such as NOX, HC, CO and PM emissions are computed using the LTO emission indices from the ICAO EEDB, FOI Turboprop and FOCA Piston Emissions reference databases, combined with the Boeing Fuel Flow Method 2 (BFFM2). PM emission indices of jet engines are estimated using the First Order Approximation (FOA4) method53, which is detailed in the ICAO Airport Air Quality Manual (Doc 9889 2nd edition 2020). En-route non-volatile PM emissions54 are calculated using the up- to-date implementation of the black carbon emissions methodology55. The IMPACT calculation methods and reference data to assess fuel burn and emissions may differ from those used by Member States to report their emissions to UNFCCC or CLRTAP, hence the delta in estimates between these data sources.
System for Airport Noise Exposure Studies (STAPES)
STAPES is a multi-airport noise model jointly developed by the European Commission, EASA and EUROCONTROL. It consists of a software compliant with Annex II of Directive 2002/49/EC and the 4th Edition of the ECAC Doc 29 modelling methodology, combined with a database of over 100 airports with information on runway and route layout, as well as the distribution of aircraft movements over these runways and routes. The STAPES airport database also includes airport- specific aircraft flight profiles and noise-power-distance (NPD) data, which reflect the local atmospheric conditions at each airport in terms of temperature, pressure and relative humidity.
Aircraft Assignment Tool (AAT)
AAT is a fleet and operations forecasting model jointly developed by the European Commission, EASA and EUROCONTROL. AAT converts a passenger and flight demand forecast into detailed operations by aircraft type and airport pair for a given future year and scenario, taking into account aircraft retirement and the introduction of new aircraft into the fleet. It is an integral part of the STATFOR 20-year forecast methodology that was followed for the EAO. The forecast operations are processed through the IMPACT and STAPES models to assess the fuel burn, emissions and noise data for years 2030 to 2050 presented in the Sector Overview chapter.
Fuel burn, emissions and noise assessment
For consistency with other international emission inventories, full-flight emissions presented in this report are for all flights departing from EU27 or EFTA, i.e. flights coming from outside EU27 or EFTA are not included. In contrast, noise indicators include all departures and all arrivals. Historical fuel burn and emission calculations are based on the actual flight plans from the EUROCONTROL Flight Data, including the actual flight distance and cruise altitude by airport pair. Default aircraft take-off weights from the ANP database (defined as a function of trip length) are used when assessing noise, fuel burn and emissions for this report; these may not always reflect the load factors and take- off weights observed in real operations. Future year fuel burn and emissions are based on actual flight distances and cruise altitudes by airport pair in 2019. Future taxi times are assumed to be identical to the 2019 taxi times; where non available, ICAO default taxi times are applied. Helicopter operations are excluded from the assessment. For years 2022 to 2030 all indicators were estimated by scaling their respective 2030 values in line with the STAFOR mid-term traffic forecast. This method may overestimate the rate of fleet renewal and lead to an underestimation of the noise and emissions during this period.
For the STAPES noise assessments, the number of airports, together with their respective runway and route layout, were assumed to be constant over the full analysis period – i.e. only the fleet, the number and time of operations vary56. The standard take- off and landing profiles in the ANP database were applied. For historical noise, the day/evening/night flight distribution was based on actual local departure and landing times assuming the Environmental Noise Directive default times for the three periods: day = 7:00 to 19:00, evening = 19:00 to 23:00, night = 23:00 to 7:00. For future years, the day/evening/ night flight distribution at each airport was assumed to remain unchanged compared to 2019. Population density around airports was also assumed to remain unchanged throughout the analysis period. The mapping of the fleet to the ANP aircraft follows the ECAC Doc 29 4th Edition recommended substitution method.
In addition to the noise contours at the 98 airports modelled in STAPES, the noise generated by aircraft take-offs and landings at all airports in the EU27 and EFTA area was estimated via the Noise Energy Index, by applying the following formula:
Ndep and Narr are the numbers of departures and arrivals by aircraft type weighted for aircraft substitution;
LAT, FO and APP are the certified noise levels in EPNdB at the three certification points (lateral, flyover, approach) for each aircraft type57.
Noise dose-response curves
To estimate the total population highly annoyed (HA) and highly sleep disturbed (HSD) by aircraft noise, the following dose-response regression curves recommended by WHO for the European region were used:
Share of population highly annoyed (%HA) = -50.9693 + 1.0168 * Lden + 0.0072 * Lden2
Share of population highly sleep disturbed (%HSD) = 16.79 - 0.9293 * Lnight + 0.0198 * Lnight2
The total population at the 98 major airports in STAPES was assessed for Lden values between 45 and 75 dB and for Lnight values between 40 and 70 dB with one decibel increment, and then multiplied by the corresponding %HA and %HSD values. As the Lden and Lnight values represent outdoor noise levels the annoyance and sleep disturbance estimates may not take into account the effect of local sound insulation campaigns for houses and buildings around airports.
Future fleet technology scenarios
Future noise and emissions presented in the Sector Overview chapter were assessed for different technology scenarios.
The most conservative ‘frozen technology’ scenario assumes that the technology of new aircraft deliveries between 2019 and 2050 remains as it was in 2019. Under this scenario, the 2019 in-service fleet is progressively replaced with aircraft available for purchase in 2019. This includes the A320neo, B737 MAX, Airbus A220 (or Bombardier CSeries), Embraer E-Jet E2, etc.
On top of the fleet renewal, technology improvements for fuel burn (CO2), NOx and noise are applied on a year-by-year basis to all new aircraft deliveries from 2019 onwards following a single ‘advanced’ technology scenario. This technology scenario was derived from analyses performed by groups of Independent Experts for the ICAO CAEP, and is meant to represent the noise and emission reductions that can be expected from conventional aircraft and engine technology by 2040.
For noise, the advanced technology scenario modelled for this report assumes a reduction of 0.1 EPNdB per annum at each noise certification point for new aircraft deliveries. For fuel burn and CO2, the advanced technology scenario assumes a 1.16% improvement per annum for new aircraft deliveries58. For NOx, the scenario assumes a 100% achievement of the CAEP/7 NOx Goals by 203659. No technology improvement was applied when estimating future HC, CO and PM emissions.
The above technology scenarios represent improvements in conventional aircraft designs, i.e. they do not take into account potential future designs like supersonic aircraft, electric/hydrogen aircraft or UAVs. For the forecast of net CO2 emissions, electric/hydrogen aircraft were assumed to enter the fleet in 2035 and bring an additional emissions reduction gradually ramping up to 5% in 2050.
Future ATM improvements
The European ATM Master Plan, managed by SESAR 3, defines a common vision and roadmap for ATM stakeholders to modernise and harmonise European ATM systems, including an aspirational goal to reduce average CO2 emission per flight by 5-10% (0.8-1.6 tonnes) by 2035 through enhanced cooperation. Improvements in ATM system efficiency beyond 2019 were assumed to bring reductions in full-flight CO2 and NOx emissions gradually ramping up to 5% in 2035 and 10% in 2050. These reductions are applied on top of those coming from aircraft/engine technology improvements.
Future SAF scenario
The sustainable aviation fuels (SAF) scenario used in the forecast of net CO2 emissions assumes that the ReFuelEU mandate proposed by the European Commission in July 2021 is met, that is, that SAF usage gradually ramps up to 20% of total fuel burn in 2035 and 63% in 2050. The lifecycle CO2 emissions of SAF were assumed to be on average 80% lower than those of fossil fuel.
53 Due to the lack of smoke number data for turboprop engines, PM estimates currently exclude this category. As an indication, turboprop aircraft represented approximately 1% of the total fleet fuel burn in 2019.
54 Non-volatile particulate matter (nvPM) refers to particles measured at the engine exit and is the basis for the regulation of engine emissions certification as defined in ICAO Annex 16 Volume II, “emitted particles that exist at a gas turbine engine exhaust nozzle plane, that do not volatilize when heated to a temperature of 350°C.
55 Stettler, Marc E. J.; Boies, Adam M.; Petzold, Andreas; R. H. Barrett, Steven (2016): Global Civil Aviation Black Carbon Emissions. ACS Publications. Collection. https://doi.org/10.1021/es401356v
56 The closure of Berlin Tegel airport in 2020 was taken into account.
57 For Chapter 6 and 10 aircraft (light propeller), the unique overflight or take-off level is used for the three values.
58 ICAO Environmental Report 2010
59 59 ICAO Environmental Report 2010