Volume 8, Number 5     September/October 2000

NASA Technology May Ease Flight Delays

Statistics show flight delays are at an all-time high, with air passenger frustrations running even higher. New technology developed by NASA Langley Research Center (LRC) in Hampton, Virginia, may help ease some of those frustrations, allowing travelers to reach their destinations faster.

NASA researchers have designed a system to predict aircraft wake turbulence on final approach, so airliners can be spaced more safely and efficiently. The technology is called AVOSS or Aircraft Vortex Spacing System.

“All aircraft produce wake vortices, sort of like two small horizontal tornadoes trailing behind the wing tips,” says AVOSS principal investigator David Hinton of LRC. “The larger and heavier the plane, the stronger the wake.” That means small aircraft that follow larger ones can encounter turbulence if they're not kept far enough apart. That turbulence can be severe enough to cause a plane to crash.

AVOSS determines how winds and other atmospheric conditions affect the wake vortex patterns of different types of aircraft. The system uses a type of laser radar, or lidar technology, to confirm the accuracy of those forecasts. All of this information is processed by computers, which can then provide safe spacing criteria.

Weather plays a big part in the motion and decay rate of these trailing twisters. Until now, there has been no system to accurately predict wake vortex patterns and quantify the spacing needed for safety. This type of data is not currently available to air traffic controllers, forcing use of rigidly fixed distances to separate distinct classes of aircraft during bad weather and causing unnecessary air traffic delays that disrupt flight schedules and increase costs.

NASA’s Aircraft Vortex Spacing System can provide the needed information. The system was installed at the Dallas-Fort Worth (DFW) International Airport in Texas three years ago and has undergone continued development and testing. Initial test results show that AVOSS can increase individual runway capacity as much as 15 percent, depending on weather conditions and the number of “heavy” aircraft arriving. Benefit studies estimate the dollar savings to airlines and passengers of this capacity gain to range from $20 million to more than $100 million per year by 2015. During the demonstration, AVOSS was not used to change the actual spacing of arriving aircraft. Wake detection lidars were used to validate system operation.

NASA demonstrated the prototype wake vortex spacing system in Dallas in July to news media, Federal Aviation Administration (FAA) officials and other government and industry representatives from the U.S., Canada, Germany, the Netherlands, the United Kingdom and Hungary.

“With a system like AVOSS installed at DFW Airport, we would have the capability to increase runway safety, while improving runway capacity by as much as 15 percent,” said Executive Director Jeff Fegan of Dallas-Fort Worth International Airport. “DFW operations average nearly 2,300 flights per day. Increasing the amount of planes that can land every hour means fewer delays for our passengers.”

NASA worked with the FAA; DFW International Airport; Massachusetts Institute of Technology's Lincoln Laboratory, Lexington; Transport Canada; Volpe National Transportation Center, Cambridge, Massachusetts; and others to develop the Aircraft Vortex Spacing System.

AVOSS is a part of the NASA Aviation Systems Capacity Program, headquartered at NASA Ames Research Center, Moffett Field, California.

Credits