Scientists to study aircraft turbulence Goal is preventing crashes between jetliners, small planes

September 13, 1996|By Tanya Jones | Tanya Jones,SUN STAFF

If you see a large airplane with colorful smoke billowing from its wings as it lands at Baltimore-Washington International Airport in the next few weeks, don't be alarmed.

It's just researchers from the Johns Hopkins University Applied Physics Laboratory (APL) testing experimental radar equipment that could prevent small planes from crashing in the spiraling air currents created by jetliners.

The researchers will be using the radar equipment and sound waves to try to detect tornadolike air currents that emanate from the wings of large planes. They will collect data from a smoke-emitting National Aeronautics and Space Administration C-130 aircraft and from large planes during regular landings at the airport.

The air currents, known as "wake vortices," have been blamed for 74 accidents since 1983, mostly cases in which a small plane attempted to land after a large plane, according to the National Transportation Safety Board.

"The turbulence created by wake vortices could cause that plane to lose control and tip over," said Dennis Kershner, director of transportation programs and development at the APL. "It is a serious concern."

In August, after recommendations by the NTSB and two accidents that killed a total of 13 people, the Federal Aviation Administration set new standards increasing to 4 1/2 miles, from 3 1/2 miles, the distance small planes should keep between themselves and Boeing 757s.

The new standards also moved several types of business jets and commercial aircraft from the large-plane to the small-plane category.

Matthew Furman, an NTSB spokesman, said yesterday that he placed more confidence in the distance requirements and the staggering of flights than in the ability of researchers to track the air currents.

"I can't imagine radar can detect this," he said. "Instead of identifying wake vortices, it's probably easier just to avoid them. The best cure is prevention."

The researchers hope that this preliminary testing will lead to an accurate way of tracking the vortices and eventually adjusting landings. Such a radar system could be made available to airports worldwide, said Helen Worth, an APL spokeswoman.

"There is really no known way at the current time to monitor the vortices and determine what their strength is and how long they persist," Kershner said. "This is just our very first test."

The C-130 is scheduled to simulate landings at BWI from 5 p.m. to 7 p.m. Thursday, and Sept. 23, 24 and 25. Radar observation of regular flights will begin before Thursday and continue through Sept. 27.

Kershner was unsure when the tracking of regular flights would begin.

A constant tone that will be used during those tests to enhance radar detection should not be audible beyond the airport, Worth said.

In October, APL researchers will take their equipment to John F. Kennedy International Airport in New York for NASA-sponsored testing to be conducted with other research institutions.

Pub Date: 9/13/96

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