Severe turbulence jolts 767 and injures 26 aboard

FORT LAUDERDALE, Fla. — It makes for a terrifying roller-coaster ride, frequently forcing planes to shake violently while plummeting hundreds of feet in a matter of seconds.

Severe turbulence hits U.S. airliners about 10 times a year and often when they least expect it — while at cruising altitude with the seat-belt sign off.

A variety of atmospheric conditions can produce turbulence, including changes in barometric pressure, air flowing over mountains and warm and cold fronts. At high altitudes, planes can run into clear-air turbulence, where strong rivers of air conflict.

During hot summer months, airline passengers tend to feel more bumps because of rising pockets of air, generated by the heating of the ground. Thunderstorms create extreme turbulence, which is why airline pilots are trained to steer well clear of them.

On average, turbulence injures 58 people on U.S. flights each year, and in most cases those people weren't wearing seat belts, the Federal Aviation Administration (FAA) said Monday. About two-thirds of incidents occur while planes are at or above 30,000 feet.

At 4:30 a.m. EDT Monday, turbulence jolted a Continental jetliner flying at 38,000 feet near the Dominican Republic, injuring 26 of the 168 passengers and crew, four seriously. Some of those had been out of their seats, walking around, authorities said.

The turbulence lasted about 10 seconds and threw panic-stricken passengers around the cabin of the Boeing 767, causing some to hit their heads on the ceiling and others to cling to their seats to keep from flying upward, authorities said. Most of the injuries involved neck and back pain, said Miami-Dade Fire-Rescue Lt. Elkin Sierra.

"It felt like the plane was falling," passenger Carolina Portella, 18, told The Miami Herald.

Flight 128 made an emergency landing in Miami at about 5:30 a.m., after being scheduled to fly from Rio de Janeiro, Brazil, to Houston. Fourteen passengers were sent to three hospitals; others were treated at the airport and released. No crew members were injured, Sierra said.

Most of the passengers continued on to Houston without incident on an afternoon flight, said Marc Henderson, spokesman for Miami International Airport.

The plane apparently ran into clear air turbulence, where strong currents of air converge.

Usually they are moving at dramatically different speeds and directions. Frequently, this kind of turbulence is produced by the jet stream or by air rolling off mountain ranges.

For pilots, it is vexing because it is hard to avoid. They cannot see clear-air turbulence ahead of them, and it cannot be detected by radar.

Since 1980, turbulence has seriously injured 358 people on U.S. flights and killed three others on flights that didn't involve a major crash, according to the FAA.

Two-thirds of those injured were flight attendants, who were often racing to secure items before returning to their seats.

In most cases where passengers were injured, they were either in the restroom, walking back to their seats or not wearing seat belts.

Although the investigation is not complete, authorities believe Air France Flight 447 flew into an area of ferocious turbulence after taking off from Rio de Janeiro bound for Paris on May 31. The Airbus A330 jetliner apparently broke apart while over the Atlantic Ocean near the equator, killing all 228 on board.

In another deadly accident, Delta Flight 191, a jumbo jet that took off from Fort Lauderdale, Fla., flew into the severe downdrafts of a thunderstorm while attempting to land in Dallas on Aug. 2, 1985.

It crashed short of the runway, killing 136 of the 163 on board as well as a motorist on the ground.