Is mid-air refuelling the future of greener aviation?

The cruiser feeder concept, developed as part of the EU-funded RECREATE project (Research for a CRuiser Enabled Air Transport Environment), would enable aircraft to take off carrying smaller amounts of fuel, reducing overall weight during take-off and ascent, with the tanks being filled fully only once a cruising altitude of 10,000m is reached.

The concept was tested by researchers at the Zurich University of Applied Sciences with the help of professional pilots flying aviation simulators.

Kerosene comprises a third of the take-off mass of a long-haul jetliner, meaning taking off with a full fuel tank by itself increases fuel consumption. Therefore even the lightest and most energy-efficient of today's aircraft are operating uneconomically. To reduce not only the energy consumption but also the carbon footprint of aviation, aircraft should take off carrying only the necessary amount of fuel to reach a flying refuelling station.

"The refuelling aircraft would carry kerosene for three to five jetliners to help reduce carbon emissions," project leader from Zurich University, Leonardo Manfriani, said. "The flying refuelling station would circle locally. It would have to be far enough from inhabited areas but on the other hand located directly on important flight routes."

Flying refuelling stations would not only allow aircraft to climb to the cruising altitude considerably lighter, they would also enable coverage of greater distances without landing an aircraft to refuel along the way, which would reduce traffic at some of the busiest air transportation hubs. Service work demands at these airports would be reduced, and so, too, would the amount of noise produced be aircraft take-offs, which are louder the heavier the aircraft. Residents near airports would thus also benefit from airborne refuelling.