Wind shear may have caused Japan plane crash

Wind shear may have caused the crash of a FedEx jet that cartwheeled on the runway at Tokyo's main international airport and burst into a fireball, investigators said Monday, but experts noted that the model was notoriously difficult to land.The American pilot and co-pilot - 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 an aircraft or smash it 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 and or lift abruptly if a headwind suddenly changes to a tail wind during takeoff or landing, said Patrick Smith, a Boston 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.

Monday's was the first deadly crash at Narita - the main air hub for international flights to Tokyo - since the airport opened in 1978.

According to the U.S. Federal Aviation Administration, pilot Kevin Kyle Mosley, 54, of Hillsboro, Ore., and co-pilot Anthony Stephen Pino, 49, of San Antonio, were killed as they landed the flight from Guangzhou, China.