Michael Braukus

Headquarters, Washington, DC

(Phone: 202/358-1979)

Kathy Barnstorff

Langley Research Center, Hampton, VA

(Phone: 757/864-9886)

Melba Williams

Dallas-Fort Worth International Airport, TX

(Phone: 972/574-6701)

RELEASE: 00-107

Sobering statistics show flight delays are at an all-time
high, with air passenger frustrations running even higher.
However, new technology developed by NASA’s Langley Research
Center in Hampton, VA, 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 Langley. “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 this information is
processed by computers, which can then provide safe spacing

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 lack of this kind of data forces air
traffic controllers to use rigidly fixed distances to separate
different classes of aircraft during bad weather, 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.

NASA plans to demonstrate the prototype wake vortex spacing
system in Dallas July 17 through 20 to news media, Federal
Aviation Administration (FAA) officials, and other government and
industry representatives.

“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, 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 Lincoln Laboratory,
Lexington; Transport Canada; Volpe National Transportation Center,
Cambridge, MA; and others to develop the Aircraft Vortex Spacing
System. AVOSS is a part of the NASA Aviation Systems Capacity
Program, headquartered at Ames Research Center, Moffett Field, CA.