Thursday, January 21, 1999

Recon team
hunts turbulence

Scientists will head into the
jet stream today to look for
turbulence that can
imperil aircraft

By Helen Altonn


A reconnaissance plane was scheduled to fly today from Honolulu into the jet stream, looking for the type of turbulence hit by Continental Flight 910 yesterday.

The flight is part of a research project to improve weather forecasts and understanding of clear air turbulence.

The turbulence that shook the Continental jet flying from Narita, Japan, to Honolulu was related to the jet stream, said Mel Shapiro, a scientist with the National Oceanic and Atmospheric Administration.

A senior research meteorologist at NOAA's Environmental Technology Laboratory in Boulder, Colo., Shapiro has long studied the problem of turbulence.

The Continental incident resulted in minor injuries to 18 passengers and four flight attendants.

"These people were lucky," said Shapiro said yesterday at the National Weather Service's Honolulu Forecast Office.

He recalled that in December 1997, one passenger was killed and 102 injured when a United Airlines 747 flying from Narita to Honolulu hit turbulence.

Shapiro is chief scientist for nine research missions being flown out of Honolulu in a Gulfstream-IV hurricane reconnaissance plane. Sophisticated instruments are gathering weather and turbulence information.

Observations on today's flight will be used to improve forecasts for a strong storm expected to strike the West Coast in two days, Shapiro said.

The scientists also are trying to learn why some areas have "wave breaking" air turbulence and others don't, he said. "We're trying to understand the environment in which these turbulent events occur."

"The way the air flows during turbulence is exactly the same way the ocean looks," he explained. "You see it every day down at the shoreline. A very stable wave is moving through the ocean, it rises up, then breaks."

In the air, he said, internal waves move through the atmosphere without turbulence. Then an unstable vertical wind sheer may occur, causing the atmosphere to break into waves.

"The wave crest rises, it curls over, then it breaks," Shapiro said. "When it breaks, you have very high frequency motions of the atmosphere."

It's like a surfer caught in a breaking wave, he said. "When a tube collapses, that's wave breaking . . . You're all over the place."

The atmosphere also may break down into turbulence over mountains, he said.

Turbulence can't be predicted precisely, but regions can be identified where commercial aircraft may encounter it, Shapiro said. The weather service provides such information in American air space.

Shapiro's group is flying into turbulent areas of the jet stream to look at the internal waves between 27,000 and 45,000 feet -- the flight altitude of major airlines.

The experiment is called SCATCAT, for Severe Clear Air Turbulence Collides with Air Traffic. It is coupled with a Winter Storm Reconnaissance program sponsored by the weather service with NOAA's Aircraft Operations Center and the U.S. Air Force Reserves.

About 13 people are here for the missions, including Jim McFadden, representing the Aircraft Operations Center in Florida, and Lt. Commander Sean White, project manager.

McFadden said today's flight will end in Long Beach, Calif., and the plane will return Friday to continue the missions.

He said "a major rain event" is expected in northern California tomorrow or Saturday.

747 had turbulence warning,
so most aboard buckled up

By Rod Ohira


Continental Flight 910's crew was alerted to turbulence ahead, and the majority of passengers had seat belts on when the jumbo jet ran into trouble, a federal investigator said.

Thomas Rea, the Federal Aviation Administration's Pacific representative, said air turbulence initially rated as "severe" caused injuries to 22 people yesterday as they flew from Narita Airport in Japan to Honolulu.

The flight, with 351 people on board, landed in Honolulu at 7:23 a.m.

Thirteen passengers, including four children ages 1 to 12, were treated for minor injuries at Queen's Hospital and released by 11:30 a.m. Four women were taken to Pali Momi Hospital and later released.

Five injured people declined treatment, according to Rea.

A United Airlines jet, flying about 10 minutes ahead of the Continental flight, warned it of moderate turbulence, Rea said. He noted there are three grades of turbulence -- light, moderate and severe.

"Absolutely, it could have been worse," Rea said.

According to the crew, the jumbo jet encountered severe turbulence three hours after takeoff, Rea added.

"The plane lost altitude -- about 500 feet -- and then climbed 1,000 feet," he said. "The aircraft did that by itself (due to the turbulence)."

The crew estimated the turbulence lasted 10 minutes, which Rea says is "extremely long."

Air turbulence in the area is not unusual at this time of the year due to the location of the jet stream, Rea said.

Except for a 12-year-old boy, who witnesses say was tossed about the cabin, passengers rode out the ordeal in their seats.

Rea said cabin damage included several broken seats and a torn oxygen mask.

"The bottom line from the FAA is keep seat belts on at all times," said Rea, who is forwarding his report of the incident to the National Transportation Safety Board.

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