Michael Braukus
Headquarters, Washington, DC                 July 13, 2000
(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

NASA TECHNOLOGY MAY HELP EASE RECORD FLIGHT DELAYS

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 
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 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.

                              -end-