US electric aircraft startup company Ampaire (founded 2016) has successfully flown its Eco Caravan hybrid-electric conversion of the Cessna Grand Caravan regional ‘feederliner’ aircraft, which is normally powered by a single turboprop engine. In the Eco Caravan conversion, the turboprop is replaced by Ampaire’s fully-integrated hybrid-electric propulsion system. The maiden flight of the Eco Caravan took place on Friday, at Camarillo in the US State of California.

“Aviation is the hardest industry to decarbonise,” pointed out Ampaire CEO Kevin Noertker. “Fully-electric aircraft are range limited because of the weight and energy capacity of current-generation batteries. Hybrid-electric aircraft, however, can preserve the range and utility of today’s aircraft. That is why we are focused on hybrid-electric propulsion for a series of increasingly capable regional aircraft. It’s a way for the airline industry to decarbonise more quickly and also to benefit from lower operating costs.”

The Eco Caravan can seat nine, and Ampaire aims to have it certified in 2024, with it then entering commercial service. This timescale should make it the first electrically-powered regional aircraft to enter commercial service. The company already has a number of firm orders, plus options, from a number of companies. The biggest such order is from sustainable regional aviation technology financing company Monte, for up to 50 Eco Caravans.  

“Launching hybrid-electric aviation is no simple task, but we have made it easier by upgrading an already certified aircraft,” he highlighted. “We will come to market more quickly and allow airlines around the world to begin to gain operational experience with this new type of propulsion. And we will work with them on follow-on models to meet their network requirements.”

Ampaire’s integrated hybrid-electric propulsion system is composed of a compression ignition engine, a battery pack in an underfuselage fairing (which replaces the cargo pannier on a standard Grand Caravan) and an electric motor. The system reduces fuel burn and carbon emissions by up to 70%. Operating costs are, depending on the carrier’s route structure, cut by between 25% and 40%. Cost per available seat mile is close to that of driving a car (in the US). The technology is scalable, so it can be used to power larger regional aircraft. The company does plan to soon develop more powerful versions of the propulsion system for larger aircraft, using a ‘building blocks’ approach.

Carrying eight passengers, the Eco Caravan actually has a longer range than a standard Grand Caravan. The range of the Eco Caravan is more than 1 600 km. The aircraft’s batteries can be recharged in flight, or by means of ground charging stations. The former capability is very important, allowing full operation into and out of places without ground recharging stations.

The first flight lasted 33 minutes and the aircraft climbed to 1 066 m; to achieve full power for the climb, the ignition engine and the electric motor were used in combination. Thereafter the plane was flown at cruising speed and different power settings were tested and data collected. “The Eco Caravan propulsion system performed just as expected,” reported test pilot Elliot Seguin. “It was smooth and quiet. All temperature and power output readings were normal.”