The invisible revolution making planes lighter

Airlines are continually finding ways to make airplanes cleaner and lighter. | Bruce Bennett/Getty Images

SUSTAINABLE AVIATION

Technology could cut carbon footprint of flying.

To the casual flier, airliners seem the same as always, except for the ever-smaller seats, non-existent meal service and seat-back screens.

There’s a revolution happening that doesn’t have to do with passenger comfort: radically reconfigured engines, novel manufacturing techniques that use less steel and more carbon fiber, and small but crucial changes that keep airplanes cleaner and thus lighter.

Aircraft may never enjoy the technology gains that transformed computers and are doing the same for solar panels — the physics of flight doesn’t allow for that — but even incremental gains can help aircraft save fuel and cut their carbon footprint.

Here are five of the many changes (some still on the drawing boards) aimed at cutting the use of fuel.

Illustrations by Luke Brookes for POLITICO

Illustrations by Luke Brookes for POLITICO

Borrowing from space

NASA promises to save America’s airlines over $250 billion a year through the technologies it developed under the $400 million Environmentally Responsible Aviation research program that ran from 2009 to 2015.

The agency came up with eight programs, including new ways of stitching together large sections of lightweight materials that weigh up to 20 percent less than the metal typically used for aircraft. The agency’s research arm also looked at how to boost the aerodynamic efficiency of engines to contribute to a 2.5 percent saving on fuel burn. Finding ways to integrate the wing and fuselage would also help aircraft fly more efficiently, said Fayette Collier, who managed the research program.

If all the new technologies developed under the program are implemented between 2025 and 2050, they could cut airline fuel use in half, pollution by 75 percent and noise to nearly one-eighth of today’s levels, NASA calculated. The plan now is to work on getting each innovation ready for commercial production.

green-clean

Getting clean

A dirty airliner is a heavy airliner, and a heavy airliner takes more fuel to fly.

Aircraft traditionally are cleaned using foam and highly pressurized water four to five times each year. It takes more than 11,300 liters of water to clean one Airbus A380 aircraft and more than 9,500 liters of water to clean a Boeing 777.

Replacing the traditional wet wash with a dry wash to clean its fleet of over 250 aircraft saves Emirates more than 11 million liters of water per year. A liquid cleaning product is first applied manually to the entire external surface of the aircraft. It’s then polished off, also removing the dirt. The aircraft is left with a protective film allowing the painted surface to remain shiny longer.

This reduces the number of times it has to be washed to about three times a year, and also cuts fuel consumption because the plane isn’t as dirty as it would be without the coating. Other companies, including Lufthansa Technik, also offer the service.

Paperless-cockpit

Paperless cockpit 

The black leather bag is as much a part of a civil aviation pilot’s image as the uniform with stripes on the sleeves and cool aviator sunglasses.

That bag contains mandatory technical manuals and route maps weighing several kilograms. It doesn’t sound like much, but that weight adds up, and in an industry where every kilogram needs fuel to get it up in the air, a lighter cockpit is greener. That’s why shifting from paper briefing books to tablets has environmental benefits.

An Electronic Flight Bag also means that charts and other documents no longer have to be printed, saving paper and ink. In addition, going electronic enables pilots to tweak flight parameters and aircraft performance using real-time wind and temperature data, contributing to a more efficient flight.

Most airlines have made the move. U.K. low-cost carrier easyJet estimates that replacing 27 kilos of paper navigational charts on each aircraft saves over 2,000 tons of carbon emissions per year. This may not be significant on a global scale, but for an individual airline, the number helps with its overall reduction target.

Electric-aircraft

Electric aircraft

Getting cars to zero emissions means going electric, and airplane makers are looking at the same long-term goal — although it’s a lot more difficult for planes than for cars.

Airbus’s research program into electric-engined aircraft illustrates the challenge.

An initial test model, called an E-Fan, crossed the English Channel in 2015. It was an all-electric twin-engine low-wing monoplane made of composite materials. The two motors were powered by a series of 250-volt lithium polymer battery packs mounted in the wings. They had enough power for one hour and took one hour to recharge.

That’s a long way from flying passengers, and Airbus shelved plans to sell the two-seat training airplane powered by electric engines, “As a leading aircraft manufacturer we are shooting for something more ambitious and timely. The E-Fan project would not have been able to scale up to this ambition,” said Airbus spokeswoman Marie Caujolle.

Airbus is working on a more powerful model called E-Fan X. The original E-Fan had two 30 kilowatt motors, the next model could fly in three years powered by a 2 megawatt motor. But a single aisle passenger aircraft would need between 20 to 40 megawatts of power. “Whether this will take another three years to happen we don’t know but for sure we need to build the 2 megawatt demonstrator,” Caujolle said.

bringing-back-the-blimp

Bringing back the blimp

People have been talking about the return of the airship ever since the Hindenburg crashed in a ball of flames in 1937, but lighter-than-air blimps and zeppelins have proven very difficult to resuscitate on a larger scale.

Now the pressure to cut the carbon footprint of aircraft is prompting designers to take a fresh look at an old technology. This month, Hybrid Air Vehicles carried out the fourth test flight of its Airlander 10 prototype airship in the skies outside London. As one of the biggest objects to have ever taken flight, the vessel can carry up to 10 tons of payload while using between 20 percent and 40 percent of the fuel required for an equivalent traditional aircraft.

U.S. defense giant Lockheed Martin got approval from the U.S. Federal Aviation Administration in 2015 to certify its hybrid airship design, with commercial roll-out set for 2018. Solar Ship is another initiative with three craft designs, each lifted by helium and powered by solar panels. The ships are perfect for getting cargo around Africa and remote areas like Canada’s north, the company said.

This article is part of a special report on sustainable aviation.