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Our team

Julien Dufour, CEO
Julien Dufour, CEO Julien Dufour is Founder and CEO at VERIFAVIA SARL and VERIFAVIA (UK) LTD.

Julien Dufour is also Director at Aviation Carbon Events Ltd and co-organiser of Aviation Carbon 2012Aviation Carbon 2013 and Aviation Carbon 2017.

Julien speaks English, French and Spanish.




Nicolas Duchêne, Technical Director, Lead EU ETS & Airport Carbon Verifier
Nicolas Duchêne, Technical Director, Lead EU ETS & Airport Carbon Verifier Nicolas Duchêne has been working on the evaluation of the impact of the aviation on the environment for the last 10 years. He has been involved in many projects aiming at providing accurate estimates of fuel, greenhouse gases emissions, local pollutants and contrails emitted by aircraft engines. Nicolas has been working with numerous partners and clients  - airlines, airports, civil aviation authorities, manufacturers, regulatory bodies from all over the world. 

Nicolas is a qualified EU ETS Lead Auditor and Airport Carbon Verifier. He is also an authorised supplier of the French method Bilan Carbone © developed by the French Association Bilan Carbone ©, which origin dates back in the early 2000's.

Nicolas also participated in various meetings of the ICAO Committee for Aviation Environmental Protection (CAEP) Models and Databases Group (MDG) on behalf of EUROCONTROL and the European Aviation Safety Agency (EASA). In the last months, Nicolas has been particularly involved on investigations related to the impact of the future CO2 standard for aircraft. He also contributed to the development of the ICAO Doc 9889 ‘Airport Air Quality Manual’. 

Nicolas holds one MSc in Industrial Sciences and Sustainable Development (from the Université de Technologies de Troyes, France) and one MSc in Water Pollution Control Technology (from Cranfield University, United Kingdom).

Nicolas speaks fluent French and English and is based in Paris.


  • Airport Carbon Accreditation Verifier, Jul 2014
  • Bilan Carbone Advanced Level (Association Bilan Carbone), Paris, 2013
  • External Lead Verifier (EU ETS), Reading, Mar 2010
Gary Cleven, Lead EU ETS & Airport Carbon Verifier, RSB/ISCC Sustainable Biofuels Auditor, ICAO MBM MRV APER Expert
Gary Cleven, Lead EU ETS & Airport Carbon Verifier, RSB/ISCC Sustainable Biofuels Auditor, ICAO MBM MRV APER Expert Gary Cleven is a Lead Auditor, Aviation and Environmental Expert with more than 25 years of aviation industry experience including EU ETS for aviation, ICAO MBM MRV, ICAO State Action Plan on Emissions Reduction (APER) and RSB/ISCC sustainable biofuel certification / auditor training.

In 2013, Gary held a key role advising the Thailand Department of Civil Aviation (DCA) on the details of a future global ICAO MBM MRV for international aviation CO2 emissions and a future national MBM MRV for the airline industry in Thailand. The training and capacity building project prepared the DCA for the ICAO 38th Assembly and the ICAO MBM MRV technical discussions that will continue until the ICAO 39th Assembly in 2016. 

Also, in 2011 and 2012, Gary worked with Verifavia as an aviation researcher during the EU CleanSky project FRARS-2 and interviewed many airlines worldwide regarding their preferences for a future environmentally friendly 'green' regional aircraft.

As an EU ETS Lead Auditor with Verifavia since 2010, Gary has performed verification audits for more than 100 large and small emitters worldwide, including airlines, cargo operators, charter operators, helicopter operators and business jet operators. 

Gary began his EU ETS career in 2009, at the inception of EU ETS for aviation, when he worked as an EU ETS Consultant assisting several airlines in the preparation and implementation of their EU ETS monitoring plans.
Previously, Gary worked as an employee at Canadian Airlines and American Airlines and as a consultant with Lufthansa Consulting, Lufthansa Systems, Sabre Consulting and SH&E. He has worked on airline IT, Network, Fleet Planning and Restructuring projects worldwide at many airlines and aircraft manufacturers, including Boeing and Airbus.


  • IATA Cargo Security Awareness (ACC3 Independent Validator preparation), Nov 2013
  • ISCC Biofuel Auditor: ISCC System Certification Seminar, International Sustainability and Carbon Certification (ISCC), Cologne, Germany, Oct 2012
  • Airport Carbon Accreditation Verifier, Sep 2012
  • RSB Biofuel Auditor: Certification and Auditor Training Course, Roundtable on Sustainable Biofuels (RSB), Kuala Lumpur, Malaysia, Sep 2011
  • External Lead Verifier (EU ETS), Reading, UK, Mar 2010
Beata Kusova, CORSIA Expert and EU ETS Verifier
Beata Kusova, CORSIA Expert and EU ETS Verifier Beata Kusova, ICAO’s CORSIA expert and EU ETS verifier, completed her master degree in International Air Transport Operations Management from ENAC (Ecole Nationale de l’Aviation Civile, France) in 2014. Beata has several years of working experience in supporting roles in aviation, notably from Airbus, Travel Service and TNT Express Worldwide.
Beata is currently working on research and marketing of ICAO’s CORSIA in order to provide related services in the upcoming years.

Beata speaks English, French and Czech, and is based in Paris.
Hélène Manzoni, EU ETS Verifier
Hélène Manzoni, EU ETS Verifier Hélène holds a Mechanical Engineering M.Sc. applied to Atmospheric Sciences from Université Paul Sabatier of Toulouse as well as an aviation specialty degree from Ecole Nationale de l’Aviation Civile (ENAC).

Since 2004, her career has been dedicated to quantifying and modelling the environmental impact of anthropogenic emissions, with the past ten years specifically from the aviation sector. Hélène was project engineer at the Air Quality and Emissions Department of Service Technique de l’Aviation Civile (DGAC) where she conducted environmental impact analyses of continuous descent approaches in close partnership with Airbus.

She was then seconded to ICAO by the French Ministry of Foreign Affairs as environmental officer to support the CAEP/9 cycle work programme. She contributed to the development of the aircraft CO2 Standard and to the publication of a number of reference documents.

She also spent four years as senior flight operations engineer at Emirates Airline, in charge of the fuel monitoring and reporting system as well as of all environmental performance indicators published by the company including EU ETS data.  

Hélène speaks French and English and holds a private pilot licence. She is currently based in Toronto, Canada.
Vikas Sharma, Business Analyst (Shipping & Aviation)
Vikas Sharma, Business Analyst (Shipping & Aviation) Vikas Sharma, a business analyst for shipping and aviation, completed his electronics & communication engineering degree from Mahrshi Dayanand University in 2011. Vikas has completed an internship in Communication, Navigation and Surveillance at Airports Authority of India.

Vikas has led several Market research analyses and made business outreach across the world. Vikas is currently working on a thorough shipping industry analysis and market research in the context of the upcoming European MRV regulations for maritime transport.