ZeroAvia has achieved its long-awaited first flight in a Dornier 228 aircraft featuring its hydrogen-electric propulsion system. The fuel-cell-based ZA600 powertrain has been installed on the 19-seat airliner’s left wing in place of one of its two Honeywell TPE-331 turboprop engines.
The aircraft took off at 1.35 p.m. local time from ZeroAvia’s research and development base at Cotswold Airport in the UK for a flight that lasted 10 minutes. The event marked the start of a flight test campaign that the California-based start-up hopes will lead to its first converted regional airliner entering commercial service in 2025.
According to ZeroAvia founder and CEO Val Miftahkov, the company will soon announce the first aircraft type to be converted to run on gaseous hydrogen, as well as a partnership with the manufacturer of that model and the launch airline customer. This will be an aircraft in the 10- to 19-seat class that will be covered by Part 23 certification rules.
ZeroAvia aims to submit a type certificate application for the 600-kilowatt powertrain, initially with the UK Civil Aviation Authority, by the end of 2023 as it works to establish the basis for the approval. It will also seek supplemental type certificates covering the conversion of each specific aircraft type.
In the longer term, the company is working on a larger 2.5-megawatt powertrain that would be suitable for aircraft carrying up to 90 passengers. It aims to start ground testing this later in 2023 and is also working to secure its design and production organization approvals.
In the current test configuration, the hydrogen-electric powertrain consists of two fuel cell stacks, with lithium-ion batteries providing peak power support during takeoff and safety redundancy.
For the test flights, the hydrogen fuel tanks and fuel cell power-generation systems were inside the cabin. For production aircraft, these will be stored outside the fuselage. Video footage of the first flight showed water vapor coming out of the fuel cells, which are made by Powercell, a ZeroAvia partner.
Testing will continue throughout this year as ZeroAvia refines its powertrain design with flights from Kemble and other airports. The initial flight lasted just under half of the technology demonstrator’s current endurance limit of 25 minutes and reached an altitude of 2,000 feet and a speed of 120 knots. ZeroAvia intends to gradually extend flight durations through the flight test campaign.
Airlines Commit to Hydrogen-powered Fleets
According to ZeroAvia, it now holds provisional order commitments covering around 1,500 of the propulsion systems. Speaking to reporters from the World Economic Forum in Davos, Miftakhov said that between 600 and 700 of these are intended for aircraft with up to 19 passenger seats. He added that the company aims to start taking deposits for delivery slots during the course of this year.
Commercial carriers that have publicly expressed interest in adding hydrogen-powered aircraft to their fleets include American Airlines, which is an investor in ZeroAvia, as well as United Airlines and Alaska Air. Miftakhov said that it is now planning a further funding round.
The gaseous hydrogen used for flight testing is produced with an on-site electrolyzer. ZeroAvia is partnered with the Scotland-based European Marine Energy Centre to establish a refueling system that it says will be a microcosm of the infrastructure to be rolled out at commercial airports.
Rival hydrogen propulsion system developer Universal Hydrogen has indicated it is close to conducting a first flight test with a larger Dash 8 regional airliner in Washington state. Both companies had intended to start flight testing in 2022 but were delayed by various factors, including technical glitches and weather.