The UK’s Civil Aviation Authority (CAA) has granted a permit to fly for ZeroAvia’s Dornier 228 aircraft, which has been retrofitted with its prototype hydrogen-electric powertrain. ZeroAvia secured the permit to fly following an extensive ground testing campaign and a rigorous review of the full development program. (Earlier post.)

Ground testing (credit Oliver Kay)

The award of the permit allows ZeroAvia to begin the first test flights of its 600kW hydrogen-electric powertrain. The 19-seat twin-engine aircraft has been retrofitted in an engineering testbed configuration to incorporate ZeroAvia’s hydrogen-electric engine powering the propellor on its left wing, operating alongside a single Honeywell TPE-331 stock engine on the right for appropriate redundancy to allow the safe testing of the novel propulsion technology.

The test flights are set to be a landmark achievement for ZeroAvia and the HyFlyer II project, a major R&D program backed by the UK Government’s ATI Programme, which targets the development of a 600kW hydrogen-electric powertrain for 9-19 seat aircraft.

For this testing program, ZeroAvia has worked with the CAA in meeting a more stringent set of requirements when compared to the E-Conditions framework ZeroAvia had used for its 6-seat prototype in 2020.

Part 21 is an industry-standard term used to describe the regulatory approval of aircraft design and production organizations, and the certification of products, parts, and appliances for aircraft. Securing this permit to fly is a significant milestone in ZeroAvia’s path towards commercialization.

ZeroAvia plans to submit a commercially certifiable configuration for ZA600 by the end of 2023, ahead of delivering powertrains for the first commercial routes for 9-19 seat aircraft to commence by 2025. ZeroAvia currently has 1,500 engines under pre-order, partnerships with seven aircraft manufacturers and multiple fuel and airport partnerships.

When test flights begin in January, ZeroAvia’s Dornier 228 testbed is expected to become the largest aircraft yet to fly using a hydrogen-electric powertrain.