From Selection to Action: Clean Aviation Call 3 Projects Kick-off in Brussels

In September 2025, Clean Aviation Joint Undertaking (CAJU) selected ATR to lead two of the four flagship projects under its Call 3 programme, a strong recognition of our expertise in regional aviation and low-emission technologies. 

That ambition has now moved into full execution. 

Earlier this year, the consortia behind the HERACLES, DEMETRA, PHARES and OSYRYS projects gathered at Clean Aviation headquarters in Brussels to officially launch a five-year collaboration aimed at shaping the next generation of Ultra-Efficient Regional Aircraft (UERA). 

This joint kick-off marked the beginning of an unprecedented coordinated effort to mature the technologies that will enable hybrid-electric regional flight, a key pillar in the decarbonisation of aviation 

A €340 Million Commitment to Regional Aviation Decarbonisation 

The four projects will benefit from €140 million in Clean Aviation funding, complemented by more than €200 million in in-kind industry contributions. 

Together, they share a common objective:
To demonstrate hybrid-electric flight technologies capable of achieving at least 30% CO₂ emissions reduction on representative regional missions. 

The European Union Aviation Safety Agency (EASA) will be involved throughout all phases, accelerating certification through early introduction of CRL criteria and assessment. 

HERACLES: Defining the Regional Aircraft of Tomorrow 

As the central architectural project, HERACLES (Hybrid-Electric Regional Aircraft Concept for Low EmissionS) defines the future Ultra-Efficient Regional Aircraft concept integrating: 

• Hybrid-electric propulsion
• High-performance batteries 
• An optimised thermal engine operating on 100% Sustainable Aviation Fuel (SAF) 
• Advanced propellers 
• Optimised aerodynamics and more-electric architecture 

Coordinated by ATR, the consortium brings together major European industrial and research leaders, including Airbus, Leonardo, ONERA, ISAE-SUPAERO, Safran Electrical & Power, Pratt & Whitney Canada, Collins Aerospace (Ireland & UK), Ratier-Figeac and CIRA. 

DEMETRA: Making Hybrid-Electric Flight a Reality 

DEMETRA is the flagship flight demonstrator of the regional stream within Clean Aviation. 

Using a certified CS-25 ATR aircraft as a flying testbed, the project will validate: 

• Hybrid-electric propulsion integration 
• Electrical and thermal system performance 
• High-energy-density battery integration 
• Ground and flight testing procedures 
• Certification pathways 

The consortium includes Airbus, Collins Aerospace UK, DNW, Leonardo, Liebherr Aerospace, Pratt & Whitney Canada and Poland, Ratier-Figeac, Safran Electrical & Power, Saft, and Thales Avionics. 

One Ambition: Entry into Service by 2035 

By coordinating both HERACLES and DEMETRA, ATR ensures close alignment between aircraft design and real-world flight validation, a decisive factor in accelerating innovation toward industrialisation. 

Building on more than four decades of experience in regional aviation, ATR ensures that the technologies under development remain directly relevant to airline operational realities. 

With the Brussels kick-off, the programme has now officially entered its implementation phase.
The journey toward the next generation of Ultra-Efficient Regional Aircraft has begun.