Wind seen as factor in jet crash
Investigators say plane hard to land
TOKYO - Wind shear may have caused the crash of a
The American pilot and copilot - the only two people on board - were killed when the MD-11 cargo plane bounced on its landing at Tokyo's Narita international airport, slammed onto the runway, and tipped onto its side before exploding into flames.
Kazuhito Tanakajima, an aviation safety official at the Transport Ministry, said the crash may have been the result of "wind shear," sudden changes in wind that can lift or smash an aircraft into the ground during landing.
But Tanakajima said the wind speed alone was not necessarily dangerous. He said there was headwind of about 45 miles per hour, and a crosswind of about 7 miles per hour.
Wind shear is a sudden change in the speed and direction of the wind, and happens relatively frequently. But a dangerous localized form - called a microburst - can cause planes to lose airspeed suddenly or lift abruptly if a headwind suddenly changes to a tail wind during takeoff or landing, said Patrick Smith, a Boston-based pilot and aviation analyst.
During the 1970s and 1980s, microbursts were blamed for a number of aviation disasters in the United States that helped usher in a new generation of wind shear detection technology.
Smith described a wind speed of 45 miles per hour as unusually powerful. "It is possible that shears from these gusts, together with known instability issues of the MD-11, led to the accident."
He said the aircraft is unusually sensitive on the controls, but the downside is a tendency for pilots to overcontrol during a bounced or otherwise unstable landing, which in severe cases can lead to total loss of control.
The MD-11 has had no fatal crashes since 1999 and was largely retired from passenger service because of the introduction of more economical planes.
Tomoki Kuwano, a former Japan Airlines pilot and aviation specialist, said the MD-11 can be hard to land.
"In the past, the MD-11 has a record of landing failure," he said. "And when that happens it often flips over."
In 1999, an MD-11 flipped over and burst into flames, killing three people during a crash landing in a storm in Hong Kong. And in 1997 one of the planes landed hard, flipped, and caught fire while landing in Newark.
Yesterday's was the first deadly crash at Narita - the main air hub for international flights to Tokyo - since the airport opened in 1978.
FedEx, which last month opened its Asian hub in Guangzhou, said it was investigating the cause of the accident.