Tag Archives: CDA

NYT looks, superficially, at aviation’s fuel-saving efforts

The New York Times has joined this month’s parade of general-interest news outlets looking at how fuel efficiency is bringing changes to the airline business. This article doesn’t mention ADS-B, RNAV, or RNP, but it does mention continuous-descent arrivals. It also takes a look at efficiency-improving products like winglets and new technologies in engine design.

The following excerpt hints at NextGen and equipage issues, but doesn’t really explain either topic:

On a recent trial flight, Southwest Airlines used satellite navigation and continuous descent approaches on a round trip between Dallas and Houston and determined it could reduce fuel consumption by 6 percent.

“If we were able to reduce and get 6 percent savings across all our flights, that would equal 90 million gallons a year in fuel reduction and a reduction in carbon emissions of 1.9 billion pounds,” said Jeff Martin, Southwest’s senior director of flight operations.

Nancy Young, vice president of environmental affairs for the Air Transport Association, said that changing from a radar-based system to a satellite-based one was “a big, big thing.”

But incorporating the new flights into an older traffic infrastructure takes time. Air traffic control centers and airlines are in transition, with some updating equipment faster than others. According to the Federal Aviation Administration, about 80 percent of American airliners have the necessary devices.

Brian Will, program manager for American Airlines and a pilot, said the agency needed to do more to reward companies that make an investment in new technology. Air traffic control “is compelled to maintain a system that will accommodate everybody,” he said. “In my opinion, this is a mistake.”

The aviation authority is considering ways to expedite satellite-guided planes through the system. “Clearly there is a policy that we’re looking at right now to try and improve our delivery of services to those who are better equipped,” said Carl E. Burleson, the F.A.A.’s deputy acting administrator for policy planning and the environment.

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Explainer: CDA at Atlanta-Hartsfield

The science and technology website Physorg.com has a brief but interesting article entitled “Continuous Descent: Saving Fuel and Reducing Noise for Airliners.” An excerpt:

Proponents hope the 90-day test at Hartsfield-Jackson Atlanta International Airport – currently the nation’s busiest airport – will move the concept one step closer to nationwide implementation. Estimates suggest that continuous descent arrivals could save a large airline as much as $80 million per year in fuel costs alone.

“In commercial aircraft, we see anywhere between 300 and 1,000 pounds of fuel saved for each arrival,” said John-Paul Clarke, director of the Air Transportation Laboratory at Georgia Tech and an associate professor in the School of Aerospace Engineering. “With fuel cost at $3 per gallon, that would amount to as much as $600 per arrival and could really add up for the airlines at a time when they need all the savings they can get.”

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Everything you ever wanted to know about FDMS

If you want or need to understand the basic concepts underlying Flight Deck-based Merging and Spacing  (FDMS), you can’t do better than this document written by John Marksteiner and Randall Bone from the FAA’s FDMS development group. It’s comprehensive, clearly formulated, and really just plain fascinating. There’s too much good material to excerpt properly, but for anyone who hasn’t yet joined the FDMS gospel choir, here’s a few graphs that summarizes some fundamental goals:

The main objective of FDMS is to achieve consistent, low variance spacing between paired aircraft at the entry to an arrival procedure (e.g., Continuous Descent Arrival) and on final approach […]

Achieving the consistent, low variance spacing is expected to reduce the time interval between the first and last aircraft in the overall arrival flow which results in increased capacity. Overall efficiency should be increased through the avoidance of costly, low altitude maneuvering.

Other benefits may be realized through FDMS. Those include the following:

  • Reduction in radio frequency congestion;
  • Increased predictability of arrival traffic;
  • Increased ability to conduct CDA operations due to consistent, accurate spacing;
  • Sustained capacity during CDA operations;
  • Reduction in the number of controller issued maneuvering instructions;
  • Reduction in ATC workload, and potentially increased sector capacity, by allowing flight crews to conduct the spacing task;
  • Reduction in the number of go-arounds caused by less than desirable spacing.

What is not fully expressed in this graph is the long-term cost, noise and environmental savings that could be achieved if the majority (vast majority?) of scheduled flights were operated using CDA. At this month’s AAAE NextGen conference in Louisville, Capt. Christian Kast from UPS told us that in their initial FDMS trials, they found that they could reduce fuel consumption in the last 25 minutes of flight by an average of 21% for B757s and 31% for B767s.

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