As is the case with most of our infrastructure, the systems that control flight patterns in the United States are out of date, and upgrading them could deliver meaningful reductions in the greenhouse gas emissions associated with air travel.
While things like smart grid and plug-in infrastructure make for much sexier headlines, upgrading air traffic control systems with GPS navigation technology and Internet-enabled communications systems could deliver up to a 10 percent reduction in greenhouse gas emissions, according to the Single European Sky ATM Research program (SESAR).
Unfortunately, it's not as simple as just outfitting planes and airports with GPS and WiFi and watching emissions drop. Some industry behavior will have to change.
There are a number of factors to look at if we want to modernize air transportation: Flights need to be able to take the most direct route possible, they need flexibility in their routes in order to take advantage of tail winds whenever possible, and they need to take off and land seamlessly without waiting on either end, says Lance Sherry, deputy director of the Center for Air Transportation Systems Research at George Mason University.
Perhaps most importantly, airlines need to not over-schedule flights, a problem Sherry says is mostly unique to U.S. airports. In Europe and in most of the rest of the world, there are capacity limits at airports, and the airlines decide among themselves who will take the noon flight on a certain route. But in the United States, where competition is king, airlines have close to free reign to schedule flights whenever they like.
"There's no one airport that's any worse than the others, they're all bad, but just as an example, at Houston airport, Continental has about 40 flights scheduled between 4 and 4:15 p.m., and you can go watch them: They line up and they idle until it's their time to go and then they fire up their engines," Sherry says.
They burn fuel and generate emissions all the while, but according to Sherry they do it because those are the time slots during which people want to fly.
"They do it to sell tickets, but they don't tell you that 40 other flights are taking off at the same time and you're going to have delays," he says. "These delays are systematic — it's not the weather, and they always blame it on the weather, and it's not air traffic control, it's the result of over-scheduling."
The only way to solve the capacity problem in the United States, according to Sherry, is to build more capacity, but the airports that most need it (Los Angles, New York, Chicago, Atlanta) are constrained either by buildings or environmental controls.
Consequently, the goal of NextGen, the U.S. version of the EU's SESAR, both of which grew out of an agreement between the U.S. Federal Aviation Administration (FAA) and the European Commission called the Atlantic Interoperability Initiative to Reduce Emissions (AIRE), is to build what Sherry calls effective capacity: in other words, a better use of existing capacity.
NextGen aims to improve both ground systems and the equipment in airplanes, but the airline industry is historically reticent to upgrade equipment, both because of the cost and because it has been burned by government advances in the past.
In the early 1990s, the government improved radar for oceanic flights with what was called FANS-1 technology. The upgrade required new equipment in cockpits, which the airlines installed, only to wait several years for the government to upgrade its ground stations in order for the new cockpit equipment to work.
It's the example the airlines point to when they explain why they don't want to run out and buy new equipment when the government says it's improving air traffic control systems. But it also gets at another key issue in improving air travel in this country: It requires cooperation between a private industry that is based on competition and profitability and a government entity that is run with the goal of providing a service.
The fuel reductions promised by air traffic control upgrades could be enough to sway the airlines, however, and several of them have been taking part in various tests that have proven the technology's potential in this regard.
Boeing's Tailored Arrivals project, for example, involved tests with several airlines over a 12-month period (March 2008 to March 2009) of a system that generated arrival plans tailored to each plane and flight. The result? The airlines cut fuel consumption by 1.1 million pounds (524 tons) and carbon dioxide emissions by 3.6 million pounds (1,600 tons) over the course of the year. That translates into savings for the airlines.
Also helpful is the inevitable inclusion of the aviation industry in the European Union's carbon trading scheme, which is scheduled to move forward in 2012. According to Sherry, a carbon cap that includes mobile sources of emissions and sets the cap low enough to put the pressure on airlines could actually spur U.S. airlines to think about solving their over-scheduling problem, too.
"The thing is, this system of over-scheduling is inherently unprofitable, but there's this idea that if we remove it we will sacrifice competition, and competition is what allows the U.S. industry to provide lowest possible fares and highest possible service to consumers," Sherry says.
Other ways to solve the over-scheduling problem include setting capacity limits at airports and auctioning off time slots (a proposal former Department of Transportation secretary Mary Peters brought to the table during her last year of office only to be met by fierce opposition from Congress and the airline lobby), and encouraging airlines to fly slightly larger aircraft slightly less frequently.
In the meantime, SESAR and NextGen are moving forward with solving the timing and route issues. In Europe, where capacity issues have been resolved, the upgrades should drastically reduce emissions. In the United States, reductions will be less impressive.
"If you fly the most direct route you will reduce emissions and save fuel, but if you have wait to take off or land you will still be wasting fuel and generating unnecessary emissions," Sherry says.
While global upgrades won't be completed until 2032 or 2036 (new procedures need to be designed and tested for the 50,000-plus flights daily, especially if planes are going to fly and land closer together than they do now), by 2016 we should have what Sherry calls "enabling technologies" in place.
The most important of these will be Automatic Dependent Surveillance–Broadcast (ADS-B), a GPS-based technology that will allow planes to fly closer together, and data-based communications between the flight tower and aircraft, which will move air traffic control away from WWII-era push-and-talk radios toward modern IM-based communication.
With these two technologies in place, new procedures will be adapted and, especially at some of the more congested airports, we should see emission and fuel reductions. And maybe even fewer delays.
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(Map: National Air Traffic Controllers Association)