A solid collaboration between SMEs and Universities

ENVISA (Coordinator)


Role in the project

ENVISA is the coordinator of the project and leads WP5 (Project Management). In addition, taking benefit from its involvement with the European Organisations and aviation environmental support activities, ENVISA leads WP3 (Impact Assessment for Stakeholders) and also supports all other work packages.


ENVISA will use its background information, data and models for conducting studies, and also contribute to WP2 on the CO2 optimisation scenario assessment. As part of WP5, ENVISA will coordinate and actively contribute to dissemination, communication and exploitation activities.

Key personnel

Ayce 700×700

Ayce Celikel


She is a founding member of ENVISA and became its President in 2007. She holds a Masters in Engineering in Environmental Management and has extensive experience in air quality studies, including regulation, assessment methodologies and effects. She has experience in leading teams on large scale European projects (EASA, Cleansky, EUROCONTROL, Europeaid). She participated in numerous international conferences and working groups specialized in aviation and the environment and has a wide knowledge of people’s perception of environmental matters. She also carried out capacity building projects like (Europeaid TRACECA, Turkish CAA, etc..). In addition she is managing the Cleansky 2 RAPTOR project with 8 European partners and is in the management board of ECATS whereas there are many scientific and technical experts network. Finally she is managing the EASA framework contract on aviation emissions for last 8 years.

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Hans Dorries


He has more than 15 years of unique airport planning and design experience including both domestic and international projects. He has served as the project manager and/or the lead technical planner on a variety of projects including: airport master plans, noise compatibility studies, airspace obstruction analyses, and aviation forecasting. Mr. Dorries also provides software functionality training and technical support services for the Aviation Environmental Design Tool (AEDT). He has served as Senior Business Analyst on business intelligence (BI) tools development projects, including dashboard, alerts and notifications, query manager, workflow manager, reports, and geographic information systems (GIS). Mr. Dorries also served as aviation faculty at the Florida Institute of Technology College of Aeronautics. He was responsible for developing and delivering courses related to airport planning and design, as well as computer applications such as the Integrated Noise Model (INM).

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Gabriel Casas is an environmental consultant who joined ENVISA after a traineeship at the Environment Department of the European Aviation Safety Agency. Gabi graduated from a B.Sc. in Environmental Science at the University of Malaga (Spain) and M.Sc. in Environmental and Resource Management at the Brandenburg Technical University Cottbus-Senftenberg (Germany). He is working on projects covering different areas, such as Life Cycle Assessments (LCAs), air quality modelling and monitoring, noise impacts studies and carbon emissions calculations.


Dr. Thomas Rötger

Senior Associate

He joined ENVISA in February 2021 as Senior Associate, taking over the lead of the REIVON project. From 2008 to 2020, he was Assistant Director Environment Technology in the International Air Transport Association (IATA), working on all technical and scientific aspects of sustainable aviation, such as noise, emissions and sustainable fuels, climate change risks and adaptation means, and developing environmental standards in aviation. He is a member of the Long-Term Aspirational Climate Goal Task Group of ICAO’s Committee for Aviation Environmental Protection (CAEP), and during his time at IATA was also member of the CAEP working groups on noise, operations, emissions, alternative fuels and impact science. He is rapporteur of the Environment and Energy working group in the Advisory Council for Aviation Research and Innovation in Europe (ACARE).

Manchester Metropolitan University (MMU)

Role in the project

MMU leads WP2 on the evaluation of theoretical potentials for reducing CO2 emissions. It is also responsible for the data preparation in WP1, CO2 calculations for base cases and scenarios in WP2 and supports the definition of measures in WP4. MMU is also responsible alongside ENVISA for the strategic management of the project and of the


ENVISA will use its background information, data and models for conducting studies, and also contribute to WP2 on the CO2 optimisation scenario assessment. As part of WP5, ENVISA will coordinate and actively contribute to dissemination, communication and exploitation activities.

Key personnel


Dr Ling Lim

Research Fellow

She has a PhD in Environmental Science and Engineering. She is a member of the CAEP Working Groups MDG, FESG and WG3 (Emissions and Technical). MDG and FESG are responsible for the modelling efforts to support activities of CAEP groups such as the ICAO Global Environmental Trends Assessment. Ling is currently the co-lead of the Greenhouse Gas Task Group (GHG TG) within MDG, providing leadership and input into activities such as GHG and LAQ modelling. She has over 15 years’ experience in the field of environmental impacts from aviation (emissions, dispersion and climate modelling). She is responsible for the development and maintenance of MMU models including the CAEP-approved FAST, COMA and LinClim. She is also on the technical panel of the SAE Standards Works A21 for Aviation Emissions Modelling. Ling has worked on a number of EU aviation research programmes (ECATS, QUANTIFY, ATTICA, TEAM_Play, REACT4C, FORUM-AE, SESAR ATM4E) and currently, AVIATOR, RAPTOR, SENECA and ACACIA.


Dr Bethan Owen


She is currently the European co-rapporteur of the CAEP WG3 and has worked in the field of aviation and environment for 25 years (emissions, inventory development, dispersion modelling and climate impacts). Before her nomination as CAEP co-rapporteur, she was a member of the WG3, MDG and FESG. She is the UK scientific advisor in CAEP on emissions and is a member of the ECAC group EAEG. She has contributed to a number of EU Framework projects including TEAM_Play, REACT4C and ATM4E, as WP lead on QUANTIFY and FORUM-AE, and is currently involved in AVIATOR, RAPTOR and SENECA.

Role in the project

TAKS leads WP1 on the elaboration of the overall methodology for the REIVON project. As part of WP1 agreement has been reached with the Topic Manager on important aspects of the project. Also it has been agreed which data sources to use in the project. Moreover, TAKS will be responsible for the impact assessment for the air transport


system as part of WP3. For this TAKS will make use of the AERO-MS which is an EASA owned impact assessment tool. As part of the impact analysis the impacts for various stakeholders (i.e. environment, airports, airlines, passengers, aircraft manufacturers) of the optimization alternatives will be assessed.

Key personnel

Andre van Velzen

André van Velzen

Managing Director

He holds a MSc in Geography from the University of Utrecht. Since 1996, André is involved in projects in the field of aviation. André is very experience with applying the policy analysis approach in studies which aim to reduce GHG emissions from aviation. Also he has been involved in both the development of the AERO modelling system and the use of the AERO-MS in over 30 studies related to emission reduction by the aviation industry. He was project leader for a policy analysis of potential measures to reduce atmospheric pollution by air traffic for the Dutch Civil Aviation Department. Furthermore, he was project leader towards the European Commission for a study to analyse the effects of the taxation of kerosene. Since André works for TAKS he has been involved in all of the TAKS studies in which the AERO-MS has been deployed (see above).

Technische Universität Hamburg-Harburg (TUHH)

Role in the project

TUHH will lead WP4, the analysis of potential measures, and coordinate the activity on the definition of measures. Also, TUHH will carry out the creation of the three network alternatives by optimizing the route network in WP2.1 for the various historical and future annual flight schedules as an input for the fuel and CO2


calculation. Moreover, TUHH will contribute to the data preparation with respect to air traffic schedule and aircraft performance data.

Key personnel

Prof. Gollnick

Prof. Dr. Volker Gollnick


He is director of the Institute of Air Transportation Systems and university professor at the Hamburg University of Technology. He has nearly 30 years of professional experience working in ministerial positions and management functions in the industry. His major contributions were in the development programmes of Eurofighter, Tiger and NH. His research focuses on the integration of classical aircraft design methods with aircraft operations and assessing feasibility and impact on the environment. His current focus is on new air transport concepts like super/hypersonic flight, urban air mobility and system of systems in aviation. His teaching activities include lectures on Air Transportation Systems, Flight Guidance and Aircraft Design. He is author/co-author of more than 150 Publications and the lecture book Air Transport System.


Kaushik Radhakrishnan


He is a researcher at the Institute of Air Transportation Systems. He received his MSc. in Aerospace Engineering from Delft University of Technology. He was involved in designing a Multi-disciplinary optimization workflow for Blended wing body configuration at the Institute of Integrated Aircraft Design. He did his Master thesis at the Institute of Air Transportation Systems developing an optimization algorithm for mitigating climate impact. He is currently also part of the Clean Sky 2 project GLOWOPT since 2019 and is contributing towards the development of the Climate functions for Aircraft Design. In REIVON project, he will contribute in generating response surface model for a fast calculation of fuel consumption and flight time, as a function of aircraft design range, number of seats and stage length. He will also be involved in formulating the optimization problem.

This project has received funding from the Clean Sky 2 Joint Undertaking under the European Union’s Horizon 2020 research program under Grant agreement ID: 101007659