DATE: Friday, March 21, 1997                TAG: 9703210680

SECTION: BUSINESS                PAGE: D1   EDITION: FINAL 

SOURCE: BY AKWELI PARKER, STAFF WRITER 

DATELINE: NORFOLK                           LENGTH:   86 lines

NASA STUDY OF WIND PATTERNS MAY SAVE AIRPORTS TIME, MONEY

Ben Barker and his team of NASA Langley researchers hunt tornadoes, but not the kind that rip apart houses or toss hapless cows.

Their quarry are wake vortexes, the invisible funnels of air that trail airplane wings in flight. When a plane tails another too closely and gets caught in a vortex, ``It can be very disquieting to the passengers,'' said Barker, project leader for NASA Langley's Aircraft Vortex Spacing System project.

To ensure safer - and smoother - rides during bad weather, air traffic controllers require pilots to fly planes farther apart. But the costs can be high: increased fuel costs and expensive delays in arrivals and departures.

NASA Langley researchers are gathering data in an attempt to prove that planes can be spaced closer during landings in bad weather.

If they're right, their findings stand to save the industry money and save passengers from annoying delays.

``We want to keep the same amount of safety but decrease the distance,'' explained Philip Brockman, a NASA physicist on the project.

Small planes' vortexes usually amount to small potatoes, but the swirling air masses produced by say, a Boeing 757, can corkscrew the plane behind it into the ground.

``Anything that generates lift, from a fly to a C-5 Galaxy, produces vortices,'' said Stephen Hannon, an engineer with Colorado-based Coherent Technologies. The larger the aircraft, he said, the more powerful the vortexes.

Coherent Technologies, an engineering consulting firm under contract with NASA, designed many of the complex systems which pack the vortex team's portable office.

Literally a lab on wheels, it consists of a 40-foot trailer crammed with seven computers, a solid-state laser, dozens of video displays and monitors, an array of oscilloscopes and cables dangling everywhere.

A sign next to the door bears the team logo - a laser zapping a vortex as the Tasmanian Devil rides inside the funnel.

In fair weather, pilots can see for themselves how close they can follow another plane without being sucked into a vortex.

But in bad weather, when a pilot can't see a plane in front of him, the tower calls the shots - on everything from distance to airspeed to the proper glideslope. As a rule, these instructions lean heavily on the conservative side.

Advantage: passengers don't see their in-flight meals a second time as a result of mid-air jostling.

Disadvantage: the current standards waste everybody's money.

Planes burn more fuel the longer they're waiting in line; airport authorities lose revenue by not being able to land more aircraft; and passengers get ticked off as flights are delayed or canceled.

Packing planes more closely together would alleviate some of that.

But not before NASA proves it can be done safely.

For the past few weeks, the team has been testing its high-tech setup at Norfolk International Airport.

The experimental system uses lidar, a combination of laser and radar, and bounces 100 laser pulses a second off dust particles in the air to create radar pictures of vortexes, Brockman said.

Differences in the speed at which the lasers bounce back - the so-called Doppler shift - let the trailer's computers paint a sequence of images from the vortexes' peak level to the time they decay over a section of runway.

The program gets between $800,000 and $1 million a year as part of NASA's Terminal Area Productivity program, which seeks to boost airports' bad-weather efficiency.

Right now the vortex project is in a data-gathering stage, but in the year 2000 NASA will present its findings to the Federal Aviation Administration and ask that a production version of the lidar-based system be used at the country's busiest airports.

With air travel becoming cheaper and more popular, airports will only get busier. A recent FAA report predicts that total air traffic to and from the United States will increase from 95 million flights in 1996 to 184 million in 2008.

Coherent Technologies' Hannon explained, ``It's a critical issue of capacity, delay hours and fuel wastage. Money's the big thing.'' ILLUSTRATION: Color Photo by Bill Tiernan/The Virginian-Pilot

A NASA photo shows the vortex created as a plane flies through red

smoke. NASA Langley researchers have set up a laser and radar system

at Norfolk International Airport to investigate these spirals of

air.

Graphic

Reading the Wind

For complete copy, see microfilm KEYWORDS: NASA WAKE VORTEX STUDY

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