Airbus to Test Tailgating to Save Fuel, Slash Costs, and Emissions

November 26, 2019

Taking a page from V-shaped bird formations – not to mention Formula 1 drivers, the Tour de France peloton, and the U.S. Air Force – Airbus next year plans to start testing the ability to have two aircraft fly closely together for long-haul trans-Atlantic flights.

While trips over the Atlantic Ocean currently fly 30-50 nautical miles – or 35-60 miles – apart from nose to tip, the Airbus "Fello'Fly" project would drop that margin to a scant 1.5 nautical miles, or about 1.7 miles.

At that distance, the trailing airplane could "surf" off the vortex of air created by the leader, allowing the second plane's pilot to dial back the engines, thereby producing fuel savings – and slashing greenhouse gas emissions – by as much as 10 percent, Airbus says. That could potentially bring major savings for airlines whose profit margins rise and fall with fuel prices.

"The core of it is a commitment to sustainable aviation: reducing fuel consumption and emissions," Fello'Fly project lead Daniel Percy said. "What we're driving is an industry-wide collaboration project. We see it that the more aircraft that can do this, the better."

The Fello'Fly program comes as policymakers, scientists, environmental advocates, and passengers have focused new attention on the environmental impacts of flying: While automakers in Europe, Asia, and even the truck- and SUV-addled U.S. in recent months have made highly publicized investments in electric vehicles, and growing shares of the regions' power providers are generating electricity from renewable resources such as wind and solar, the aviation industry remains entirely dependent on fossil fuels.

New research this fall meanwhile revealed that greenhouse gas emissions from air travel are outpacing even the dire predictions from the United Nations, which projected that emissions of heat-trapping carbon dioxide would triple by 2050.

"Opportunities like this for 5-10 percent fuel reduction would be gigantic; it's a very big opportunity compared to a lot of other stuff that we do," Percy said.

The tests, conducted with Airbus's new wide-body A350 aircraft around southern Europe, won't have passengers on board when they begin in 2020. If successful and approved by regulators – a process expected to take years – the company emphasizes that travelers won't feel like they've signed up for the Blue Angels or Thunderbirds stunt teams: Domestic flights in the U.S. already maintain distances as close as 2.5 nautical miles, and in Europe about 4 to 5 nautical miles.

"When you see pictures of geese flying in the sky – it's not the same: Most people wouldn't want to walk or run 3 kilometers, so the planes are quite a long way away still," Percy said. "But that's facilitated by a lot of technology being brought into the air-traffic control world."

fello-fly-flight-demonstrator-project-6.jpg
Airbus plans to start testing the ability to have two aircraft fly closely together for long-haul trans-Atlantic flights. A trailing airplane could "surf" off the vortex of air created by the leader, allowing the second plane's pilot to dial back the engines. / Credit: Airbus

Even so, introduced amid intense scrutiny and news coverage around automated systems in the new Boeing 737 MAX passenger jet, and how faulty flight-control devices and alleged lax oversight by regulators contributed to two deadly crashes of the aircraft, Airbus will likely face a far different and more difficult task of assuring travelers that its Fello'Fly project is safe.

"With all the scrutiny on the regulators, I would expect them to be more cautious," said Dave Emerson, a partner and longtime aviation expert in the Airlines practice at Bain & Co.

Wake vortices are generated as planes' wings slice through the atmosphere. The swirling trails of air are invisible to the naked eye, and they can take minutes to dissipate. Like a boat's wake in water, can cause considerable turbulence, making them potentially treacherous.

A Learjet following a large airliner too closely crashed in Mexico City in 2008, for example, killing all nine people on board. An American Airlines flight in November 2001 also crashed in New York City after flying across wake turbulence during takeoff, killing all 260 people on the plane, although a federal investigation subsequently attributed the chief cause of the crash to pilot error.

"The bigger the plane, the bigger the disturbance," Emerson said. "If you happen to fly through at the wrong time and the wrong place, you can drop or lose control."

Advances in technology and pilot training, however, have mitigated much of the risk, experts say – and Airbus' Percy emphasized that the company will only pursue Fello'Fly if it's deemed safe. Crucially, the U.S. and European governments are implementing GPS technology for trans-ocean routes that once lacked even rudimentary radar coverage, and on-board computer systems can track and adapt to other planes' position nearby. The U.S. Air Force tested a version of vortex surfing in 2013, although the results of the program remain unclear.

"As technology improves and understanding improves, there's a much better understanding of wake vortexes and where they are, and how to take advantage of them, than there used to be," Emerson said.

Fello'Fly is part of Airbus's response to the International Civil Aviation Organization's pledge last month to halve the industry's emissions by 2050, relative to 2005 levels. Already, manufacturers were seen as nearing a ceiling on just how efficiently they can make their engines and airframes – Fello'Fly has the added benefit of being cheaper, too.

Airbus's redeveloped A330Neo, which produced fuel savings of about 12 percent, came at an estimated cost of $1.8 billion.

Even if successful, it's the airlines that will ultimately be responsible for implementing a wake surfing program like Fello'Fly, and that remains an open question. While there may be plenty of opportunities to match flights within the high-density long-haul corridors from East Coast airports to London, and from West Coast airports to Tokyo and Beijing, such pairings – unlike the wine pairings taking place in first-class – require new levels of scheduling and coordination, including between rival airlines.

But if fuel prices soar – or airlines come under increasing pressure to slash their greenhouse gas emissions – vortex surfing may soon become one of the last ways for airlines to significantly boost their efficiency. Even as the International Civil Aviation Organization last month pledged to halve the industry's emissions by 2050 relative to 2005 levels, manufacturers have been nearing a ceiling on just how efficiently they can make their engines and airframes.

Meanwhile, Airbus's redeveloped A330Neo, which produced fuel savings of about 12 percent, came at an estimated cost of $1.8 billion.

"The manufacturers are reaching diminishing returns on increasing the fuel efficiency. And there are no great substitutes for long-haul flying, so it's difficult to mitigate the carbon footprint if you can't keep getting more efficient," Emerson said. "This is a potentially clever way of saying we can make a difference here without having to come up with some new breakthrough technology."