A4Climate Consortium:
United for Climate-Neutral Aviation

About

The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) is Germany’s national research and technology centre for aeronautics, space, energy, transport, security and defence. DLR’s work spans a wide range of applications, delivering results and innovations that benefit industry and business, government agencies and the public sector. At the heart of DLR’s mission is its commitment to society, which it fulfils through extensive knowledge sharing and targeted technology transfer. Therefor it is funded through federal resources. The German Space Agency at DLR is responsible for planning and implementing German space activities on behalf of the federal government. Additionally, two project management agencies at DLR manage research and industrial funding programmes.

Earth’s climate is changing, along with global mobility and technology. DLR harnesses the expertise of its 51 research institutes and facilities to develop solutions to these challenges. All 11,000 employees share a common mission: to explore Earth and space while developing technologies for a sustainable future. DLR’s technologies are not confined to the laboratory, but are transferred to wider society, strengthening Germany’s position as a prime location for research and industrial innovation.

Role in the project

DLR’s Institute of Atmospheric Physics, with its Department of Cloud Physics, has a strong research focus on the climate impact of aviation, specifically on quantification of aviation’s non-CO2 effects. This includes the contrail model CoCiP, used for climate friendly aircraft routing and to assess the effects of fuel and engine technology on emissions and climate. The department head Prof. Christiane Voigt also leads the A4Climate consortium.

The Flight Experiments Facility operates the HALO research aircraft, and is expert for in-flight emission and contrail measurements.

Team

About

INCAS – National Institute for Aerospace Research and Development “Elie Carafoli” is Romania’s leading aerospace research institute and a key player in Central and Eastern Europe. With over 70 years of tradition, INCAS conducts fundamental and applied research in aerodynamics, flight dynamics, aerospace structures, propulsion, advanced materials, testing equipment, and atmospheric observation systems. The Ambient Aerodynamics Unit contributes to atmospheric research through studies on cloud and aerosol microphysics, measurement of pollutant concentrations, and Earth Observation using LiDAR and GIS technologies. These activities are supported by a high-level research infrastructure, which includes airborne platforms and ground stations, integrated into European research networks. A central element supporting these activities is the Beechcraft King Air C90-GTx aircraft, equipped with two under-wing cloud probes: CAPS (Cloud, Aerosol and Precipitation Spectrometer) and SPEC Hawkeye.

Role in the project

Within A4Climate, INCAS brings in relevant expertise in airborne measurements and scientific analysis of microphysical properties of clouds and will be involved the Aerocloud mission and analysis of data collected with cloud probes.

The INCAS team will actively participate in the activities of work package number 2:

• Task 2.1: Preparation of aircraft, selection of aerosol instrumentation
• Task 2.2: Scientific instrument operation and technical data evaluation
• Task 2.3: Scientific data evaluation

Team

About

Current research at the Max Planck Institute for Chemistry (MPIC) aims at an integral understanding of chemical processes and related effects in the Earth system, particularly in the atmosphere, biosphere, and oceans. Investigations address a wide range of interactions between air, water, soil, life and climate in the course of Earth history up to today. The MPIC was founded in 1912 as the Kaiser Wilhelm Institute for Chemistry in Berlin, and it was relocated to Mainz in 1949. Currently, the institute employs some 350 staff in four departments (Aerosol Chemistry, Atmospheric Chemistry, Climate Geochemistry, and Multiphase Chemistry) and additional research groups. Scientists conduct laboratory experiments, collect samples and record measurement data during field campaigns utilizing airplanes, ships, and vehicles. The practical work is complemented with mathematical models that simulate chemical, physical, and biological processes from molecular to global scales. One of the major goals is to find out how air pollution, including reactive trace gases and aerosols, affect the atmosphere, biosphere, climate, and public health.

Role in the project

The group of J. Schneider, part of the Aerosol Chemistry Department at MPIC, conducts particle composition measurements during the aircraft-borne mission AEROCLOUD. Two aerosol mass spectrometers, namely the single particle instrument ALABAMA and a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS) will be used to identify aircraft emission particles in cirrus and contrail residuals, but also in the surrounding cloud-free air. The group leads work package 2 which is coordinating the A4Climate part of AEROCLOUD. Additionally, the group is part of work package 1 and takes part in a ground-based field measurement campaign close to a commercial airport.

Team

About

Imperial College London is a world-leading university renowned for excellence in science, engineering, medicine, and business. The Department of Civil and Environmental Engineering solves global challenges across the natural and built environment through world leading education, research and innovation. Imperial research is advancing sustainable aviation through innovations in advancing understanding of aviation non-CO2 impacts, understanding of low-carbon fuels and cleaner propulsion systems.

Role in the project

Imperial is leading Work Package 1. This work will focus on key knowledge gaps on how cleaner engines and Sustainable Aviation Fuels (SAF) influence contrail formation. By identifying how volatile particles (vPM) like oil droplets and sulfates trigger contrails in the absence of soot, WP1 will support the development of future low-emission engine technologies with lower climate impact. Imperial’s work will use state-of-the-art experimental measurements to advance the modelling of ice nucleation in contrails. Imperial is also a contributor to WP5, responsible for running simulations of contrail climate impacts under several future scenarios.

Team

About

The Johannes Gutenberg University Mainz (JGU) addresses climate change and sustainability through several pathways. With the Institute for Physics of the Atmosphere (IPA), JGU contributes with meteorological research to the topic of climate change. IPA focuses on physical and chemical properties of the atmosphere with a special interest in the upper troposphere and lower stratosphere. IPA has a strong background in performing airborne experiments, performing technical data evaluation as well as scientific analysis of airborne observations especially humidity observations including model comparison. IPA has expertise in airborne experiments dedicated to sample contrails and exhaust plumes of aircraft. IPA’s background extends also in the research area of non CO2 effects from aircraft, especially of ice supersaturated regions as a prerequisite for contrail formation.

Role in the project

In A4CLIMATE the role of JGU is to lead WP4 and brings in it’s expertise. During the HALO AEROCLOUD mission, JGU performs humidity observations with in situ instrumentation including technical analyses, followed by the performance of the scientific humidity analysis and determination of ISSRs (WP 2.3). Further, JGU analysis also relative humidity observations of previous aircraft missions to investigate regions of ice supersaturation, the prerequisite for contrail formation, and assesses the humidity forecast of ECMWF IFS data as well as improving the ERA5 NWP humidity data sets by using Artificial Neural Network methods based on available observational data sets (e.g. IAGOS data) in WP4.2.

Team

About

In the group of atmospheric environmental analytics, we focus on the chemical characterization of particulate matter from urban, rural and remote locations, from the boundary layer to the upper troposphere and lower stratosphere. We develop new approaches involving high-resolution mass spectrometry, such as non-target analysis after chromatography, or in-situ real-time mass spectrometry, to understand how anthropogenic emissions have changed the natural composition of our atmosphere.

Role in the project

We will perform a comprehensive physicochemical characterization of aviation-related PM emissions. Measurements will be conducted at a major airport using state-of-the-art aerosol instruments to analyze particle size distributions, chemical composition, and volatility. Additionally, offline samples will be collected for further detailed chemical analysis. The research will assess the real-world contribution of volatile PM (vPM) to total PM emissions from aircraft exhaust in the vicinity of airports. Advanced mass spectrometry techniques will be used to achieve a high level of detail in the chemical characterization of vPM, identifying e.g. engine-specific tracers.

Team

Role in the project

We will be using the state of the art Portable Ice Nucleation Experiment (PINE) chamber to conduct studies into the formation of contrails. We will do so by burning a variety of fuels in a Honeywell Auxiliary Power Unit and sampling the exhaust into PINE.

Team

About

The Department of Meteorology of the University of Reading does fundamental research in weather, climate, atmospheric physics and related fields. For A4Climate, Reading provides expertise in radiative forcing, reduced complexity climate models, CO2 equivalence metrics.

Role in the project

Reading assesses the climate outcome of contrail avoidance for optimized flights using different CO2 equivalence metrics and time horizons.

Team

About

FLIGHTKEYS – an Austrian-based global flight planning service provider – has been founded in April 2015 by a team of passionate and high profile aviation experts with very specific knowledge and long-term experience in the field of flight planning & optimization:
“Our mission is to completely re-write the science of flight management for the 21st century by precisely meeting the emerging requirements of cost-optimized airline operations, trajectory-based operations and reduction of emissions. Our research takes place in a corporate climate that promotes innovation, continuous search for excellence and ensures we have fun in what we are doing. Our focus is on affordable, user-friendly systems that provide the ultimate level of cost optimization and integrate seamlessly into future airline operations and ATM systems. FLIGHTKEYS 5D – as the only 21st century flight management system – will balance airline network throughput, greenhouse gas emissions and safety in the most cost-efficient way and covers a scope far beyond any solution currently available on the market. By improving communication and collaboration amongst stakeholders in the aviation industry it will lead to a smarter and more productive use of aircraft and airspace. Our vision is now swiftly taking shape in an unprecedented clean-sheet development approach with a fast-growing team of top software developers and aviation experts. So watch us closely, or feel free to invite us to present our new 5D solution.”

Role in the project

FLIGHTKEYS performs two roles, first as a Work Package (WP) Lead and secondly as a project partner.

As WP 3 Lead we assist in facilitating the execution of the flight trials and data collection to be carried out within our WP tasks.

Additionally, as a project partner, we are supporting the development of contrail flight trail research by collecting and assisting in the analysis of trial data.

Team

About

Founded in the Netherlands in 2000 and expanded to 13 offices across the globe, To70 is one of the world’s leading aviation consultancies.

To70 serves the aviation community by designing and optimising airport and airspace operations. Its mission is to help society and industry address the air transport challenges they face by delivering outstanding independent consultancy services.

Society’s growing demand for transport and mobility can be met in a safe, efficient, environmentally friendly, and economically viable manner. With a diverse team of experienced aviation consultants who possess first-hand knowledge across diverse range of aviation topics, To70 provides practical solutions and expert advice for its clients.

Role in the project

​To70 BV (To70) will support the A4Climate project by creating recommendations for policy measures and leveraging their experience in airspace and airport operations to support mapping of non-CO2 climate costs against operational costs of non-CO2 mitigation measures. To70’s experience in translating aviation specific research, data and analysis to policy makers on both national and international levels will ensure strong dissemination of A4Climate results, which prove to be beneficial for the sector and the climate.

Team

About

PNO Innovation GmbH (PNO) is part of the PNO Consultants Group, the European leader in collaboration engineering, consultancy and management services for international research and technology related partnerships. Based in Munich and active since 2006, the team provides strategic and operational support throughout the entire innovation lifecycle—from concept development and funding acquisition to project implementation, stakeholder engagement, and impact realisation. With experience in over 28 EU-funded projects, PNO Innovation GmbH helps research institutions, companies, and public bodies turn complex ideas into successful collaborations. Its multidisciplinary team applies proven methodologies across sectors such as aviation, energy, health, and security, supporting the transition to a greener, more innovative Europe.

Role in the project

PNO brings long-standing expertise in managing European research and innovation projects. Within A4CLIMATE, it helps ensure smooth coordination, efficient collaboration, and high-quality outcomes. PNO supports partners with planning, reporting, and risk management, while also driving communication, dissemination, and stakeholder engagement. Its work strengthens project impact, fosters knowledge sharing, and helps connect scientific results with industry, policy, and society.

Team

About

Sopra Steria Group is a major Tech European player in consulting, digital services, and software development. The company is recognized for its expertise in system engineering, ATM operations, and data platforms enabling service interoperability, as well as its strong capabilities in simulation tools and innovative digital solutions.

With its unique positioning combining technological excellence and support for digital transformation, Sopra Steria helps its clients achieve tangible and sustainable results, while strengthening both performance and innovation capacity.

Role in the project

​Sopra Steria Group (SSG), as task leader, develops and delivers software interfaces to visualize contrail-related information such as predictability, uncertainty, climate impact and costs. Based on stakeholder requirements, SSG ensures user-oriented design and integrates results on mitigation measures (SAF, advanced engines, climate-optimized routing). SSG also defines representative use cases to demonstrate functionalities and leads the mapping of operational costs of non-CO₂ mitigation options.

Team

About

TUI fly Germany is one of five airlines within the TUI Group – the world’s leading integrated tourism business. Under the umbrella of TUI Airline, the Group operates a fleet of around 130 aircraft with more than 8,000 colleagues based in Germany, the Netherlands, Belgium, the United Kingdom and Sweden, flying to over 180 destinations worldwide.

With its 23 modern Boeing 737 aircraft, TUI fly Germany connects travellers to the most popular holiday regions, including the Mediterranean, the Canary Islands, the Cape Verde Islands, Madeira and Egypt.

TUI Airline is currently renewing and modernising its European fleet with the latest generation of Boeing 737 aircraft. The aim is to make flights more economical, cost-efficient and carbon-efficient. In addition, TUI Airline has committed to ambitious emission reduction targets and is the first leisure airline with validated science-based targets.

Role in the project

TUI fly is the sole airline participating in the project and will provide ~400 flights for which contrail optimised flight plans will be generated and flown. Based on specific atmospheric conditions specific flights will be selected for post flight contrail avoidance assessments.

TUI’s key tasks, apart from executing the flights will be to provide route specific data may also include flight plans, location data, wind and temperatures. The airline will also provide operational observations and highlight complexities related to all phases of trials, which will include flight plan configuration stage, dispatch clearance, in-flight execution and data feedback to inform future flight planning.

Team

About

Contrails.org is a non-profit applied research organization that brings together leading scientists, technologists, and industry experts to accelerate the scientific research, technological innovations and operational improvements needed to make contrail management a practical reality.

Role in the project

Support research activities with model and data access.

Team

About

The Maastricht Upper Area Control Centre (MUAC) manages the upper airspace (from 24,500 to 66,000 feet) over Belgium, the Netherlands, Luxembourg and north-west Germany – one of Europe’s busiest and most complex airspace areas. 

We are pioneers in the delivery of customer-focused, reliable and impartial air traffic management services. 

We are the only cross-border civil-military air navigation service provider in Europe and have played a pivotal role in integrating European airspace, building our services around traffic flows not national borders. 

Role in the project

Maastricht Upper Area Control Centre (MUAC) has a unique expertise in operational contrail mitigation.

In 2021, MUAC conducted the world’s first large-scale and long-duration trial, which was a groundbreaking effort to better understand contrail prevention. This pioneering work continued in 2023 when MUAC carried out the first real-time simulations with 23 air traffic controllers to delve into the complexities of contrail prevention. MUAC developed the first operational network of ground-based cameras for contrail detection, a project that has been in place since 2023. This innovative approach has significantly advanced our ability to monitor contrails. Furthermore, in 2024, MUAC contributed to a 100-flights trial at the request of German authorities. This trial provided valuable insights and evolved towards a constant operational procedure. Most recently, MUAC conducted a second large-scale and long-duration trial that began in 2024 and concluded in 2025.

These efforts have been instrumental in advancing our understanding and capabilities in this field.

MUAC offers its capabilities for the operational validation of contrail mitigation to A4Climate, whether it is initiated by airlines or air navigation service providers (ANSPs). Our expertise in this area ensures that both airline-initiated and ANSP-initiated contrail mitigation strategies are effectively validated and operationalized. We are dedicated to supporting environmentally sustainable aviation practices and look forward to collaborating with the project partners on these initiatives.

The research questions will iterate around the possibilities to synchronise and optimise flight operations with air traffic control, in order to maximise the positive climate impact of contrail mitigation and minimizing eventual additional fuel burn.

Team

About

ETH Zurich creates value for society and contributes to the sustainable and prosperous future of Switzerland through its core activities of world-class teaching, pioneering research, effective knowledge and technology transfer, and proactive dialogue. It formulates specific institutional objectives and measures, linked to its core activities and success factors.

Role in the project

​ETH brings in its specific expertise in the Lagrangian analysis of atmospheric phenomena (incl. ISSR and ice clouds), and objective identification of weather systems, which will be used for the flow-dependent analysis of ice supersaturation and its predictability. ETH has access to IFS ensemble forecasts in full vertical resolution, which is essential for investigating the predictability of ice supersaturation. Within A4Climate, it will lead the flow-dependent analysis of RHi and its predictability.

Team