There’s real pressure on the aviation industry to introduce faster, cheaper and greener aircraft, while maintaining the high safety standards demanded of airlines worldwide.
Airlines carry more than three billion passengers each year, which presents an enormous challenge not only for aircraft manufacturers but for the civil aviation infrastructure that makes this extraordinary annual mass-migration possible. Many international airports are close to or already at capacity. The International Air Transport Association (IATA) has estimated that, without intervention, many global airports – including major hubs such as London Heathrow, Amsterdam Schiphol, Beijing and Dubai – will have run out of runway or terminal capacity by 2020.
The obvious approach to tackling this problem is to extend and enlarge airport runways and terminals – such as the long-proposed third runway at London Heathrow. However there may be other less conventional alternatives, such as introducing in-flight refuelling for civil aircraft on key long-haul routes. Our project, Research on a Cruiser-Enabled Air Transport Environment (Recreate), began in 2011 to evaluate whether this was something that could prove a viable, and far cheaper, solution.
If in-flight refuelling seems implausible, it’s worth remembering that it was first trialed in the 1920s, and the military has continued to develop the technology ever since. The appeal is partly to reduce the aircraft’s weight on take-off, allowing it to carry additional payload, and partly to extend its flight range. Notably, during the Falklands War in 1982 RAF Vulcan bombers used in-flight refuelling to stage what was at the time the longest bombing mission ever, flying 8,000 miles non-stop from Ascension Island in the South Atlantic to the Falklands and back.
The world’s first in-flight refuelling in 1923. Credit: AF.mil
Reducing take-off weight could offer many benefits for civilian aircraft too. Without the need to carry so much fuel the aircraft can be smaller, which means less noise on take-off and landing and shorter runways. This opens up the network of smaller regional airports as new potential sites for long-haul routes, relieving pressure on the major hubs that are straining at the seams.
There are environmental benefits too, as a smaller, lighter aircraft requires less fuel to reach its destination. Our initial estimates from air traffic simulations demonstrate that it’s possible to reduce fuel burn by up to 11% over today’s technology by simply replacing existing global long-haul flight routes with specifically designed 250-seater aircraft with a range of 6,000nm after one refuelling – roughly the distance from London to Hong Kong. This saving could potentially grow to 23% with further efficiencies, all while carrying the same number of passengers the same distance as is possible with the current aircraft fleet, and despite the additional fuel burn of the tanker aircraft. More here In-flight refuelling for airliners will see non-stop services shrink the globe.