ZeroAvia has announced a major milestone in its development of hydrogen-electric aviation, completing a full flight profile ground test of its certification-intent low-temperature proton exchange membrane (LTPEM) fuel cell power generation system (PGS) for the ZA600 powertrain.

The test simulated a 250-nautical-mile flight in a Cessna Caravan 208b, equivalent to a journey from London Heathrow to Dublin Airport. Over 2 hours and 38 minutes, the fuel cell system demonstrated stable power output and reliable performance across the balance-of-plant components. Each 200kW-capable module produced 170kW for take-off, 132kW during a 23-minute climb, and 83kW for a 90-minute cruise.

The ZA600 hydrogen-electric powertrain, designed for aircraft with up to 20 seats, will comprise four 200kW modules powering ZeroAvia’s 600kW electric propulsion system. The system delivers DC power to four inverters, which supply AC to four segments of the proprietary motor. This segregated architecture allows the motor to operate at full power even in the event of a component failure, ensuring high fault tolerance.

ZeroAvia has achieved a multi-stack balance-of-plant architecture capable of delivering a 1.4 kW/kg power density, and the certification-intent ZA600 is progressing towards approval with the UK Civil Aviation Authority (CAA).

A significant innovation highlighted in the latest testing is the integration of a bespoke passive Venturi ejector device, developed in collaboration with The Lee Company, for hydrogen recirculation within the fuel cell system. The compact Venturi replicates the performance of a conventional electrically driven hydrogen blower, but without parasitic power draw, enhancing overall specific power and reducing potential failure points.

“The Venturi not only improves system efficiency, it also simplifies certification, relying on DO160G environmental qualification rather than the more stringent DO254 required for complex hardware,” said Val Miftakhov, Founder and CEO of ZeroAvia.

ZeroAvia’s ZA600 PGS is the first fuel cell module globally designed to meet CS-E and CS-23 certification requirements. With core powertrain components already in bench testing, the company will soon progress to full engine ground testing of the final design. The company attributes the rapid development to investment in its 2MW-capable fuel cell test laboratory at its Gloucestershire R&D centre, which enables both open-frame and certification-intent system testing.

Val Miftakhov added: “We have demonstrated what is possible on shorter-range flights, and now the final design is meeting customer needs on the ground while pushing the boundaries of performance with new innovations. The Venturi is just one of several pioneering innovations—including novel humidification and gas distribution systems—that have a direct path to aviation qualification and certification.”