Dutch start-up Conscious Aerospace plans within the next three years to fly a De Havilland Canada Dash 8-300 retrofitted with a hydrogen fuel-cell powertrain being developed as part of a state-funded project to mature the underlying technologies for zero-emission flight.

A Conscious Aerospace-led consortium was recently awarded €73.3 million ($86 million) by the Dutch government’s Luchtvaart in transitie green aviation fund for the four-year second phase of its HAPSS project.

But, says chief executive Erik Geertsema, that figure will be more than matched by industry, giving a total spend in the region of €150-160 million.

Building on initial scoping and market analysis work carried out over the 2022-2024 period – a €10 million effort – the latest step aims to “fly a fully certifiable liquid hydrogen electric propulsion system” by 31 March 2029, the project’s end date.

Additionally, while HAPSS seeks to stimulate Dutch domestic production capacity, the consortium also includes three overseas entities among its 10 main participants: Switzerland’s EH Group, Magna Steyr of Austria and Senior UK.

During the project’s first phase, Conscious Aerospace also carried out initial design studies for the powertrain’s architecture to ensure it would fit within the existing nacelle structure on the Dash 8-300 for its Pratt & Whitney Canada PW123 engines.

Sized to deliver around 1.7MW – slightly below the 1.8MW maximum output of the PW123 – each powertrain comprises a fuel cell stack, the balance of plant, a heat-management system, an electrical distribution system, twin electric motors and a reduction gearbox.

Cryogenic liquid hydrogen will be stored in metallic tanks located in the aft fuselage, in a sectioned-off area between the rear emergency exit and the baggage compartment.

Range is pegged at 400nm (750km), including reserves, which “covers almost all routes flown by existing Dash 8-300 fleets”, the company says.

However, because of the additional weight and volume requirements of the fuel tanks, seating capacity slips to 29-30 passengers.

Geertsema says while the project will attempt to maximise the turboprop’s seating capacity, “the objective we are really after is a certified solution”, adding: “If we have to sacrifice [space for] another couple of passengers, so be it,” he says.

While the end of the project should be marked by the first certification test flight of the powertrain – installed in place of one of the two thermal engines – a maiden sortie is likely to take place around a year earlier as the company works with the European Union Aviation Safety Agency (EASA) through a recently agreed “innovation partnership” contract with the regulator.

Conscious Aerospace is seeking EASA certification for the powertrain, which it expects to achieve around the turn of the decade.

It would then be retrofitted on to the Dash 8-300 – and then only to the -311 variant – via a supplemental type certificate.

Although Conscious Aerospace sees only a modest market for the retrofit activity, forecasting a maximum demand of 50 shipsets, this is not the main aim of the project, says Geertsema.

Instead, the objective is to prove the company’s “credibility and capability” as an integrator for future line-fit work.

“The whole point of the strategy is that you have to believe there is a place for a new turboprop with such propulsion units.

“Our chosen market entry is retrofitting – if we end up with only 10 or 20 in this low-volume, low frequency, to prove we have solved all the issues and that we are a credible partner, I think we would be happy as well,” he says.

The only way to “secure a seat at the table” when an airframer launches a new programme is “if you have something that has proven its value – and the best is to have a product that is certified [and] flying”.

Geertsema points out that Conscious Aerospace has the full support of De Havilland Canada on the project and “exclusivity on the Q300 product line”.

A former Fokker Aircraft and Fokker Services executive, Geertsema says De Havilland Canada was selected because one of the critical issues for the manufacturer will be how it extends the life of older airframes through the introduction of new technology.

“They have to look at it the way Fokker Services has done for a quarter of a century: how do I maintain my customers? How do I lengthen the lifecycle of the asset?

“One of the options could introducing a new propulsion technology into older airframes.”

Notably, De Havilland Canada is also contemplating a return to serial production of a modernised version of either the Dash 8-300 or -400, with a decision planned next year.

Geertsema says a hydrogen fuel cell powertrain could be one option for the rebooted airliner, if there is sufficient customer interest.

“During that [operator] engagement, from a sustainability option perspective, the Conscious Aerospace solution has been advertised and used as an example of what it could look like,” he says.

Of course, Conscious Aerospace is not alone in eyeing a fuel cell conversion of the Canadian airframer’s twin-turboprop airliners: US-headquartered ZeroAvia is also modifying a Dash 8-400 with its 2MW-class ZA2000 powertrain in collaboration with Alaska Airlines.

ZeroAvia is also starting out with a smaller 600kW powertrain for sub-19-seaters, helping to prove the market for and viability of hydrogen propulsion before stepping up to bigger aircraft.

But Geertsema welcomes the competition, noting there is room for more than one player in the space.

“I think it’s important there are many companies in this field, because if there was only one you could ask the question is that really the answer?”

He also defends the decision to enter the market with a 1.7MW system, adding that “probably history will tell” if it is the correct strategy.

Meanwhile, Conscious Aerospace has recently embarked on a “big funding round” to ensure it has sufficient capital to bring the powertrain into production.