Almost half a century after the first de Havilland Canada DHC-7 – or Dash 7 – commuter aircraft took flight, a 45-year-old derivative is being transformed to help develop the platforms of the future.
In 1975, a prototype of the four-engined, 48-seat turboprop departed Downsview airfield near Toronto to commence flight testing and demonstrate short take-offs and landings for awkward-to-access locations.
Now, a Dash 7 from Canada’s Air Tindi is about to become a testbed for NASA to explore how battery-electric propulsion can be evolved to cut fuel burn and emissions for regional airliners.
Tests of new aero-propulsion systems from a range of suppliers have already powered small electric prototypes, from air taxis and flight trainers to old and all-new airframes. But there remains vast divergence of opinion about the weight, performance and viability of batteries for future fleets.
Almost five years ago, Canadian seaplane operator Harbour Air became the first to fly a battery-electric commercial aircraft when it started testing a 1950s DHC-2 Beaver retrofitted with a battery-electric powertrain from Seattle-based propulsion company Magnix.
Delighted with the results, the airline recently ordered 50 of the powertrains to electrify more of its 44 aircraft, beginning with DHC-2s from 2026, as well as converting aircraft for other operators, the first of which, fellow Canadian carrier Bel-Air, just signed a letter of intent for three conversions.
The opposite, however, is true for Italian airframer Tecnam, which last year discontinued a programme with Rolls-Royce to develop the P-Volt, an all-electric version of its nine-passenger P2012 Traveller.
Tecnam declared that battery technology “is not yet ripe”, and that for now, risks delivering “a mere ‘Green Transition flagship’ rather than a real player in the decarbonisation of aviation”.
But others see battery-electric propulsion rapidly ripening as both a step-change to more complex but capable hybrid propulsion, or an evolving standalone energy source, delivering ever-greater range, payload, and promise for deployment on larger aircraft.
“Battery technologies have largely evolved based on demand, of which road transportation – cars and buses – are the predominant transportation use case,” says Joshua Ng, director, Alton Aviation Consultancy.
“With increasing demand, there will be more research and development into battery technology to provide the capacity, range, or battery lifespan needed for aviation applications.
“It is worth noting,” he adds, “that while the energy chemistries for SAF [sustainable aviation fuel] and hydrogen are known and cannot change, batteries have the potential to grow their energy storage capacity and narrow the gap between the energy storage potential of kerosene-based or hydrogen-based fuels and batteries.”
California-based Ampaire typifies this stepped transition, having developed the Electric EEL, a converted Cessna 337 Skymaster, and the larger Eco Caravan, a hybrid-electric Cessna Grand Caravan.
It is also using a 19-seat DHC-6 Twin Otter in electric aircraft validation tests with NASA, additionally progressing towards its own hybrid-electric model: the four-motor Eco Otter, and has conceptualised a clean-sheet, fully electric design, the Tailwind.
“Hybrid electric technology only gets better and offers greater efficiencies as battery technologies improve, and as cheap electric charging infrastructure gets rolled out in more locations over time,” says Ampaire.
“These transformational capabilities are not dependent on any novel future technology or infrastructure, but achievable right now.”
In 2025, Dovetail Electric Aviation, an Australian-Spanish partnership, is planning the first flight of a battery-electric Caravan floatplane in Australia, targeting certification in 2026, the same year it plans to retrofit a hydrogen-electric powertrain on a Beechcraft King Air testbed.
“We’re focusing on a technology which is matured today, and that is battery,” says Dovetail chief executive David Doral. “It can fly maybe 100 kilometres [54nm], maybe a little bit more, and it’s easy to bring to market.”
There will always be a case for battery-only propulsion, he says, for very short flights such as sightseeing and skydiving, but adds: “We see it as an introductory technology. We think the real change is going to be hydrogen. Before we see batteries flying a 400 kilometre radius, hydrogen-electric will be a reality, we think in the next four to five years.
“It will be more capable, extending over 300-400 kilometres, and as we progress that’s when we’ll be able to move beyond to 500, 600, 1,000 kilometres.”
Dovetail has booked orders valued at $160 million for 72 battery-electric or hydrogen-electric conversion kits and, like Ampaire, counts the rapidly expanding UK-based lessor Monte as a customer.
Monte specialises in low- or no-emission regional aircraft and declares itself agnostic on green propulsion technologies.
“Approximately 20,000 aircraft are currently suitable for retrofitting with battery-electric, hybrid-electric or hydrogen-electric propulsion systems,” the company says. “Our current expectation is that the technology to retrofit aircraft to these propulsion technologies will be approved and certified by 2025.”
The company will also work with manufacturers to finance and lease new zero-emission models as they are certified to fly.
Beyond Ampaire and Dovetail, the lessor’s partners include hydrogen-electric pioneer ZeroAvia, Regent Seagliders, Cranfield Aerospace, Eviation, and Natilus.
The evolution of battery technologies is central to NASA’s Electric Powertrain Flight Demonstration (EPFD) programme, in which the Dash 7 testbed will be used to assess deployment of hybrid propulsion on regional airliners.
The aircraft’s outboard Pratt & Whitney Canada PT6A turbine engines will be replaced with Magnix-supplied magni650 650kW powertrains to demonstrate fuel savings of up to 40% and increased performance from hybrid-electric propulsion systems, enabling their use on aircraft seating up to 50 passengers.
A preliminary design review process has been completed and the testbed – now carrying the registration N650MX – was unveiled in its new livery at Boeing Field, Seattle in late August. Future flight testing of the aircraft, which was previously registered C-FJHQ, will take place from Moses Lake, Washington.
“Significant advancements have been made in battery technology in the last five years,” says Ben Loxton, the Magnix vice-president overseeing the company’s participation in the EPFD programme.
“Today, electric aircraft once considered out of reach are commercially viable on short routes such as those operated by Harbour Air in Vancouver.
“This marks the beginning of entry into service for electric flight, and further advancements in battery technology will make it viable on more and more routes, opening up its adoption further,” he says.
“Battery-electric will likely find its way into large aircraft through hybridisation,” Loxton believes, “offsetting fuel burn by reducing the cost of operation and lowering emissions.
“One benefit of hybridisation is that once installed, the batteries can be upgraded as the technology improves, offering gains in performance and further reduction in emissions as battery technology further evolves.”
Cirium fleets data shows that the NASA-Magnix testbed is one of only 13 Dash 7s still in operational use, from a production total of 113. Airframe donor Air Tindi flies seven of those remaining aircraft, which are aged between 39 and 46 years – underscoring the possibilities to renew and decarbonise old types with new propulsion systems instead of waiting for all-new designs to arrive.
Among the recipients of new US grants to progress low- or no-emission flight was New York-based Wright Electric, which is developing high capacity, ultra-lightweight batteries to power aircraft seating 100-plus passengers.
The $3.34 million grant it received under the US Federal Aviation Administration’s FAST programme will help fund construction of highly dense batteries which the company says have roughly triple the energy per pound of weight than today’s best electric car batteries.
“When Wright Electric was founded in 2016, the idea of a battery that would allow aircraft to fly regional routes with reserves seemed like a fantasy to most people,” says chief executive Jeff Engler.
“Now we are one of several companies with a viable path toward a technology that will enable regional aircraft flights entirely on battery power.”
