Will New GPS System Save Airline Fuel and Curb Emissions?

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By 2011, the nation's airports will process 2.75 billion passengers, a nearly 30% increase from 2006, according to the International Air Transport Association. With staggering growth comes staggering pollution from an industry already one of the top contributors of carbon emissions (and exempt from coverage under the Kyoto Protocol), not to mention dangerous congestion that costs airlines, flyers and businesses $9.4 billion each year.

The aviation sector is becoming increasingly aware of it's big environmental footprint, as evidenced by today's announcement of an industry-wide goal of cutting carbon dioxide emissions to half the 2005 levels by 2050. Industry leaders are in New York asking the United Nations to consider their plan to make all industry growth carbon-neutral by 2020, improve fuel efficiency by 1.5% each year over the next decade, and to submit plans for joining a global carbon trading scheme to the UN by November 2010. Even so, Greenpeace has criticized the announcement as hollow and too little, too late.

Still, it's clear airlines will soon be asked to do their part, and one of the tools at hand is likely to be a close look at the current air traffic control system, which is archaic and inefficient. It's a system based on World War II-era technology: radar. When a commercial plane flies from New York to Los Angeles, for example, its route is not determined based on efficiency but a zig-zagging line of radar fixes.

"Radar is extraordinarily safe, but we need improved efficiency," said Mike Wilson, president of ITT, Advanced Engineering and Sciences, the company charged with implementing the GPS-based system that will revolutionize the skies, called ADS-B. "(And) with efficiency, you will get reductions in fuel and emissions."

ADS-B, or "advanced dependent surveillance broadcast," is central to NextGen, the Federal Aviation Administration's (FAA) plan to modernize the National Airspace System. Already the technology has been launched in Louisville, Kentucky and South Florida and is stopping congestion, increasing safety and cutting greenhouse gas emissions by maximizing efficiency, according to Wilson.

Two years since ITT was awarded the FAA contract to develop ADS-B, the corporation is now well on their way to implementation, said Wilson. By September 2010, ITT anticipates nationwide roll out of ADS-B in more than 80 air markets, including Houston, Philadelphia, Anchorage and many more.

ADS-B will give both pilots and controllers a full view of traffic at all times. The radar screens that are currently the primary navigation tool update every five to ten seconds; with planes equipped with GPS, the navigational screens will update within hundreds of milliseconds, said Wilson.

Wilson explained that right now pilots fly based on what air traffic controllers tell them, meaning they have no situational awareness. ADS-B would supply pilots with 3-dimensional graphical maps and weather information, while broadcasting the plane's position to air traffic control via an extensive network of ground stations, which can receive a signal up to 200 miles away. This way, pilots do not have to fly according to the availability of radar towers, but according to the shortest, most efficient route.

Because both pilots and air traffic controllers would have a constant view of the airspace, the safe distance between planes would be smaller, both in the air and during landing. According to an article in Popular Mechanics, a single runway could then handle a plane every 45 seconds, increasing capacity by 25%.

Wilson described a scenario all too familiar: the pilot announces you're landing in 20 minutes, but in 20 minutes you're still circling your destination because of traffic.

"Often planes extend flight times for safety," he said. "With the efficiency provided by ADS-B, we'll be shaving minutes off every flight by removing inefficient maneuvers."

According to Wilson, one minute of flight time burn hundreds of pounds of jet fuel and is equal to three times that in carbon emissions. By decreasing flight time by one minute, thousands of pounds of greenhouse gas emissions would be eliminated, he said.

"I can say confidently, millions and millions of pounds of jet fuel will be saved by the components of NextGen and ADS-B," he said.

Even before ADS-B became an FAA goal, UPS had been testing the technology at their Louisville, Kentucky, hub, and seeing significant savings through Continuous Descent Approaches or CDAs.

Ever wondered why your ears begin to pop when you're still 300 miles from the airport? It's because pilots begin to descend in steps as directed by air traffic controllers, so that planes can be spaced safely for landing. A CDA, enabled by the efficiency afforded by ADS-B, is when a plane coasts into the landing strip at idle speed as opposed to the traditional step-down landing.

According to a fact sheet provided by UPS, "early data suggests CDAs will save 40-70 gallons per landing when compared to traditional step-down landings. In addition to fuel savings, test data suggests, CDAs can minimize noise emissions by 30% and nitrous oxide emissions by 34%."

Although UPS remains "a living laboratory" for ADS-B and the FAA has mandated outfitting all commercial airliners by 2020, the airlines are the ones who must pick up the bill. UPS is currently conducting one experimental flight sequence per week in Louisville, and asserts that before equipping all of their planes for ADS-B, "We want to make sure we have good information -- both for ourselves and the industry as a whole -- before we do anything."

With that said, only time will tell if ADS-B will actually do much to curb emissions. There's also the possibility that the improved efficiency will be offset by increasing air traffic. ADS-B may end up being more useful for meeting demand and shaving some dollars off ticket prices than saving total emissions.

From Popular Mechanics: End of Flight Delays? FAA's GPS Fix Could Bust Sky Gridlock >>

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