Universal Hydrogen has flown a 40-passenger regional airliner using hydrogen fuel cell propulsion.

It is the largest hydrogen fuel cell-powered aircraft to take to the skies so far and the largest to cruise principally on hydrogen. It flew for 15 minutes and reached an altitude of 3500 metres above sea level.

The flight, conducted under an FAA Special Airworthiness Certificate, was the first in a 2-year test campaign that is expected to culminate in 2025 with passenger services using ATR 72 aircraft.

In the test flight, one of the aircraft’s turbine engines was replaced with Universal Hydrogen’s fuel cell electric, megawatt-class powertrain. The other remained a conventional engine for flight safety.

The powertrain is built around Plug Power’s ProGen family of fuel cells that have been modified for aviation use. The powertrain does not use a battery; the fuel cells drive the electric motor directly, reducing weight and cost.

The motor, a modified magni650, and the power electronics, were supplied by magniX.

US carrier Connect Airlines, which will begin regional turboprop services this spring, has placed a first-position US order with Universal Hydrogen to convert 75 ATR 72-600s to hydrogen powertrains. Deliveries will start in 2025.

Connect’s ATR 72s will be converted using an aftermarket retrofit conversion kit, avoiding the need to develop a brand new aircraft. Also, the hydrogen fuelling system uses modular capsules that are compatible with existing freight networks and airport cargo handling equipment.