Firefighters and a bulldozer try to dismantle fuselage of the crashed cargo plane at Narita Airport in Narita, east of Tokyo, on Monday. (Shuji Kajiyama/Associated Press)

A FedEx cargo plane smashed into a runway and burst into a ball of fire while attempting to land at Tokyo's main international airport Monday, killing the American pilot and co-pilot.

Investigators believe wind shear, or a sudden gust of wind, may have been a factor. But questions were also being raised Monday about the safety of the MD-11, a wide-body airliner built by McDonnell Douglas and based on the DC-10.

The flight from FedEx's hub in Guangzhou, China, appeared to bounce after its initial touch down, and then skipped along the main runway at Narita Airport before flipping over and coming to a fiery halt, footage from airport security cameras showed.

Firefighters and rescuers immediately swarmed the MD-11 plane but the pilot and copilot — Kevin Kyle Mosley, 54, and Anthony Stephen Pino, 49 — were killed. Mosley lived in Hillsboro, Oregon, while Pino was from San Antonio, Texas, according to online records at the Federal Aviation Administration.

They were the only two people aboard.

Investigators said the accident may have been caused by low-level turbulence or "wind shear," sudden gusts that can lift or smash an aircraft into the ground during landing, said Kazuhito Tanakajima, an aviation safety official at the Transport Ministry.

Unusually strong winds of up to about 76 km/h were blowing through Narita City on Monday morning around the time of the crash, according to the Japan Meteorological Agency.

But Tanakajima said the wind speed at the time of the accident was not enough to be considered dangerous, unless wind shear was involved. He said there was headwind of about 72 km/h, and a crosswind of about 11 km/h.

Strong winds and turbulence have caused other recent incidents at the airport.

Last month, a flight from the Philippines was jolted by severe turbulence as it circled prior to landing, injuring 50 passengers and crew members.

History of accidents

The MD-11 has been involved in accidents in which it flipped while landing, and pilots have complained about the aircraft in the past. The plane is no longer used by carriers for passenger travel but is widely employed for moving cargo.

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, N.J.

Tomoki Kuwano, a former Japan Airlines pilot and aviation expert, said that although wind shear could not be ruled out, the MD-11 has a tendency to be unstable during landing.

"In the past, the MD-11 has a record of landing failure," he said. "And when that happens it often flips over."

FedEx said it was investigating the cause of the accident.

"We will continue to work closely with the applicable authorities as we seek to determine the cause for this tragic incident," it said in a statement.

The plane smashed into the longer of Narita's two runways, which remained closed Monday with all incoming flights diverted, said airport spokeswoman Misuho Fukuda.

Blaze continued for hours

Parts of the wreckage were still burning hours after the crash, forcing the cancellation of dozens of flights. At least 10,000 passengers were affected, according to airlines contacted by the Associated Press.

Japanese media reported that Monday's was the first fatal crash at Narita Airport, a major international hub located about 60 kilometres east of central Tokyo. It is Japan's second-busiest airport, after Tokyo's Haneda Airport, which is used primarily for domestic flights.

Last month, FedEx opened a new $150 million operations hub for the Asia-Pacific region in Guangzhou.

Sandra Munez, a spokeswoman for FedEx in the U.S., said customers that had packages on the plane will be dealt with on an individual basis through the company's risk management and claims departments.

"As soon as the authorities give us permission, we contact customers and notify them of the incident," she said.