Unexpected Turbulence Still A Threat

Sept. 11, 2012
The cost of violent turbulence to passengers and the airlines comes in the form of personal injury, damage to planes and occasionally emergency landings

Frequent business traveler Allen Crockett learned a painful lesson about how wind turbulence can jolt even big airline jets.

He bolted for the lavatory before landing during what had been a calm American Airlines flight from Chicago to Raleigh, N.C., in 2006. But the MD-80 suddenly lurched violently, banging Crockett's left knee against the toilet bowl to partially tear a ligament and his right hand against molding to rupture a tendon.

"Two surgeries later they still hurt," says Crockett, 50, a wireless sales executive from Clayton, N.C., who flies 125,000 miles a year.

As the skies have grown safer without a fatal U.S. airline crash in nearly four years, air-safety analysts warn that wind turbulence -- which can bounce a plane dozens of feet while landing or taking off and hundreds of feet while cruising -- lingers as a rare but real way of getting hurt when flying. About a dozen people suffer serious injuries in the air each year because of turbulence.

"It's the last of the unanticipated threats," says Christopher Herbster, associate professor at Embry-Riddle Aeronautical University in Florida. "It's one of the last really big hazards for things you don't know are out there."

Reports from the National Transportation Safety Board reveal that since the start of 2007, at least 49 crew members and 14 passengers were seriously injured, which typically means a trip to the hospital, in flights over the U.S. Dozens more suffer minor injuries each year.

Airlines must report incidents with injuries or serious damage to the plane to the NTSB, and they occasionally report less-serious incidents. The reports describe passengers breaking ankles or fracturing ribs while dashing to the lavatory or simply leaving a seat belt unfastened. Flight attendants are hurt even more often and often worse when thrown across the cabin like dolls or crushed by beverage carts.

The cost of violent turbulence to passengers and the airlines comes in the form of personal injury, damage to planes and occasionally emergency landings. But the industry doesn't compile or put a dollar tag on them, says Airlines for America, the group representing major U.S. airlines.

Air-traffic controllers warn pilots about storms. Pilots try to dodge rough spots. But despite precautions, turbulence is a threat to any flight.

"Even Air Force One has to fly around the thunder," President Obama said in apologizing for a late arrival July 19 in Jacksonville.

And when it hits, the only real precaution passengers have against being injured is their seat belts.

Turbulence causes

Turbulence comes generally in two ways: One is often called wind shear, when wind changes speed or direction, either vertically or horizontally. The other is when air moves up and down, subject to buoyant changes, such as in a thunderstorm.

Either way results from the aircraft traveling through changes in air currents. Herbster compares these changes in air speeds to a river in which there can be mild ripples on the surface when moving slowly or whitewater flowing faster around rocks.

"As the river flows faster, the surface becomes chaotic," Herbster says. "If it flows fast enough, you get rapids."

The hazard with clear-air turbulence is that the jostling wind isn't signaled by clouds like a storm is. Pilots try to warn each other about rough patches, but the system is imprecise.

"If it's reported turbulence, they will try to get to an area higher or lower, where there is no turbulence or deviate the route around the turbulence," says Al Yurman, a safety consultant and former NTSB investigator. "But the clear-air turbulence is unexpected."

In the worst cases, pilots make emergency landings to get medical care for the injured. NTSB reports describe:

A June 12 United flight from Houston to New York hit severe turbulence at 22,500 feet over Texas. The pilot landed in Lake Charles, La., because two flight attendants were seriously injured.

A flight attendant and an elderly passenger she was helping to the lavatory were hurt when a thunderstorm popped up quickly at 38,000 feet over Louisiana on June 28, 2010, jolting an American Eagle flight from Greensboro, N.C., to Dallas. The flight attendant was unable to walk and the passenger was bleeding from the mouth, so the pilot landed in Longview, Texas.

A passenger who had been up from her seat was found unconscious and bleeding on the floor of a Continental flight from Rio de Janeiro to Houston on Aug. 3, 2009, after two or three "very large jolts." The pilot landed in Miami.

Toni Higgins, a former flight attendant for Midwest Airlines, was thrown against the ceiling from her jump seat and knocked unconscious during a flight from San Francisco to Milwaukee in 2003. The turbulence coming off the Rocky Mountains unlatched overhead bins. Oxygen masks dropped. Passengers screamed.

"It's almost like a bucking horse," says Higgins, who now trains union leaders at the Association of Flight Attendants.

Because of the injuries, the pilot made an emergency landing in Denver. Passengers held onto Higgins, who lay immobilized on the floor with her pelvis fractured in three places, and another flight attendant, who broke her leg in two places. "I ended up in the trauma hospital for nine days and was out of work for 11 months," Higgins says.

Hazardous workplaces

Turbulence is part of why airlines are a hazardous place to work. More than eight out of every 100 air transportation workers were injured in 2010, which was higher than most industries other than health care and construction and public safety, according to the Bureau of Labor Statistics.

"These are not your usual workplace situations," says Rep. Mazie Hirono, D-Hawaii, who has worked for years to apply federal workplace safety standards to flight attendants.

NTSB reports describe the risk of not remaining strapped into seats during a flight:

On March 20, a Southwest flight attendant fractured a rib while trying to strap into her seat before three jolts hit the flight from Tampa to Phoenix while cruising over Oklahoma.

On July 11, 2009, a Republic Airlines passenger broke his ankle while returning from the lavatory before landing in Indianapolis from Washington, D.C. The passenger left his seat despite a flight attendant warning him it wasn't safe because of moderate turbulence.

On July 10, 2009, a JetBlue flight from New York was descending toward Fort Myers, Fla., "dropped about 20 feet instantaneously," followed by a quick lurch up in less than a second, despite no signs of trouble on radar. The seat-belt sign had been on for four minutes, but one unbuckled passenger fractured two ribs when she slammed into the stowed tray table in front of her and another passenger in a lavatory suffered two spinal fractures.

Carol Margolis, a travel consultant and author, says she quickly forgot her disappointment with a messy lavatory on a Delta flight a few years ago from Salt Lake City to her home in the Orlando area when "the plane felt like it literally dropped out of the sky." Passengers screamed and cans rolled away from the beverage cart, she says.

"I hadn't yet closed the bathroom door and the turbulence had the accordion-style door slamming into my hand over and over again," she says.

Avoiding all turbulence has proved elusive.

Air traffic controllers scan weather radar to warn pilots about storms they can fly around or over. In a relay system dating to the 1940s, pilots describe the location and height of rough patches to controllers to pass along to colleagues flying the same routes. "We tell everyone else," says Dale Wright, director of safety and technology for the National Air Traffic Controllers Association.

Ground-based radar can peer through storms and can even observe turbulent air traveling away from thunderstorms, but the equipment to see clear-air turbulence has been too large historically for the nose of a plane.

Costly detection equipment

Kennedy Space Center has equipment that can see changes in air movement with height because wind shear can affect rocket launches. Herbster compares this ability to seeing the wavering images around the gas nozzle while refueling a car, as the light bends while passing through gas fumes.

Herbster says it would be possible to place similar equipment in places such as the mountains near Denver to monitor the wind shear that makes clear-air turbulence. But he says it would be costly to deploy a network of such devices.

Airlines take precautions. American Eagle asks pilots to avoid thunderstorms by 20 miles, although that still left the June 2010 flight vulnerable to a thunderstorm that bloomed up 5 miles ahead.

Because of a March 2009 turbulence accident, Delta changed its manual: from flight attendants "should be seated immediately" to "must be seated with seat belts and shoulder harnesses secured" when facing moderate or severe turbulence.

Safety experts stress the importance of remaining belted in as much as possible during flights.

But Michael Barr, a safety expert who flew with the military and is now a senior instructor at the University of Southern California, says captains must gauge how long to keep the seat-belt sign lit because frustrated passengers will ignore it if left on for too long.

"You're damned if you do or damned if you don't if you're the captain of the airliner," Barr says.

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