Saturday, August 8, 2009

NASA system warns of turbulence ahead

A new $2 million warning system funded by NASA could help pilots avert rough patches, easing passenger jitters and dodging the type of hard knocks that hit a Boeing 767 jet Monday and injured 28 people.
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Such "clear-air" turbulence lurks without clouds, any warning or a storm in sight. It can cause upheavals in flight attendants with the strongest of intestinal fortitudes and rattle even the grittiest of pilots, not to mention passengers.

Flight instructor Scott Haun knows those knocks well.

"Even a drop of 15 to 20 feet is substantial if you're not belted in," said Haun, owner and chief flight instructor for Voyager Aviation at Merritt Island Airport. "It's sort of like going off-roading in your car without a seatbelt."

In two years, pilots will have new tools, aided by artificial intelligence, to allow them to better tell when the ride is about to get bumpy.

The National Center for Atmospheric Research is developing a prototype system to provide pilots with real-time updates about severe storms and turbulence in remote ocean regions. The prototype system spots turbulence in clear air as well as within storms and is on track for testing next year.

It will guide pilots away from severe weather, such as the thunderstorms suspected of bringing down Air France Flight 447 into the Atlantic Ocean on June 1 and the turbulence Monday that shook the Continental flight north of the Dominican Republic.

All 216 passengers and 12 crewmembers died when the Air France Airbus went down.

Passengers' heads slammed into the 767's luggage bins Monday when the Continental flight hit severe turbulence halfway between Puerto Rico and Grand Turk island. The flight was en route to Houston from Brazil, a hotbed corridor for tropical summer turbulence.
Turbulence maps

Both incidences might have been averted through the NCAR system, which is being developed with $2 million from NASA.

"This has certainly lit a fire under us to take a closer look at turbulence in that area," said John Williams, project scientist at NCAR in Boulder, Colo.



The system could be made available to pilots through private weather vendors, or airlines could use it directly, he said.
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It combines satellite data and computer weather models with artificial intelligence methods to identify and predict rapidly changing storms and other potential turbulence.

When finalized in about two years, the system could provide pilots and ground-based controllers with text-based maps and graphical displays that show regions of likely turbulence and storms. They'll provide up-to-the-minute maps of turbulence.

During the summer season, the tropics are among the worst turbulence areas in the world, as thunderstorms form and move quickly, rendering pilot briefings and weather updates useless.
Tracking air

Pilots say they have little to go by when it comes to clear-air turbulence.

They alert each other. But typically, weather satellites are the only source of turbulence information to guide them over remote regions of the Atlantic. Satellites usually provide images less frequently over water than land, making it tough to capture fast-changing conditions.

Clear-air turbulence "is like a sideways tornado," said Joe Hurston of Titusville, who has flown on humanitarian missions through the same area that the Continental jet did. "It is probably the most deadly of all because there's no indication."

Pilots of transoceanic flights get preflight briefings and in-flight weather updates every four hours during strong storms. They have onboard radar. But that only reflects off dust and water droplets, not moving air. And there's less dust at high altitudes.

Turbulence also is often far from the most intense rain.

The NCAR system uses an artificial intelligence technique, known as "random forests," to provide short-term turbulence forecasts. The technique, used to forecast thunderstorms over land, employs "decision trees." Each tree casts a yes or no "vote" on crucial storm elements at future points in time and space, allowing scientists to forecast storm strength and movement over the next few hours.
Scary times

Better turbulence warnings might ease those foreboding thoughts among frequent fliers whose stomachs sink as fast as the plane's altitude.

Jody Pollard's did about five years ago, when the 37-year-old Rockledge woman was flying from Orlando to Atlanta. Midway through the flight, the plane hit heavy turbulence.

"I just remember clutching the armrest, but it only lasted maybe a minute," Pollard said.

Henry Barnes, 69, of Melbourne flew about once a month during his 20-year career as a furniture salesman. He endured some turbulent times, but he had little choice but to continue flying because of his work schedule.

"There were quite a few times I was nervous up there, but we were always fine in the end," he said.

FLORIDA TODAY staff writer Michelle Spitzer contributed to this report.

Contact Waymer at 242-3663 or jwaymer@floridatoday.com.

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