SION, SWITZERLAND — H55, the Swiss specialist in certified electric propulsion, has announced significant progress in the development of its 200 kWh Energy Storage System (ESS) for the RTX Hybrid-Electric Flight Demonstrator. This development follows the successful completion of the project’s first full-power system test in June 2025.

ADVANCING REGIONAL AIRCRAFT EFFICIENCY The demonstrator, a collaborative effort led by RTX’s Pratt & Whitney Canada and Collins Aerospace, is designed to achieve a 30% improvement in fuel efficiency for regional aircraft. The architecture integrates an advanced thermal engine with a 1-megawatt electric motor and H55’s specialised battery system. Pratt & Whitney Canada has utilised H55’s battery architecture and safety mechanisms as the certifiable foundation for the propulsion system, leveraging a platform that has already accumulated over 2,000 hours of flight operations without incident.

SCALABLE CERTIFICATION FOUNDATIONS H55’s ESS is engineered for the rigorous demands of aviation certification, featuring a lightweight, modular design that facilitates flexible aircraft integration. Notably, the cell architecture has already completed relevant European Union Aviation Safety Agency (EASA) test campaigns.

Rob Solomon, CEO of H55, highlighted the significance of being selected as a certification foundation: “Pratt & Whitney Canada didn’t just purchase our batteries — they built their demonstrator’s compliance baseline on an architecture that H55 has already flown… and validated through EASA test campaigns”.

The programme marks a transition for H55 technology from smaller CS-23 category aircraft into the Part-25 / CS-25 category of regional transport aircraft. The technology is currently being prepared for integration and flight testing on a modified De Havilland Canada Dash 8-100.

LEGACY OF INNOVATION Born from the Solar Impulse project, H55 brings more than two decades of electric aviation experience to the RTX demonstrator. Sébastien Demont, CTO and Co-Founder of H55, stated: “We are not adapting a concept, we are scaling a proven, validated platform. This is what it means to build technology that is certifiable by design”.