Probe focuses on icy wings

WASHINGTON - Speculation over the crash of a single-engine turboprop plane into a cemetery shifted to ice on the wings yesterday after it became less likely that overloading was to blame, given that half of the 14 people on board were small children.

While descending Sunday in preparation for landing at the Bert Mooney Airport in Butte, Mont., the plane passed through a layer of air about 1,500 feet that was conducive to icing because the temperatures were below freezing, according to AccuWeather.com in State College, Pa.

Safety experts said similar icing conditions existed when a Continental Airlines twin-engine turboprop crashed into a home near Buffalo Niagara International Airport last month, killing 50. A possible aerodynamic stall in which ice causes the plane to lose lift, and the pilot's reaction to it, has been the focus of the Buffalo investigation.

Mark Rosenker, acting chairman of the National Transportation Safety Board, told reporters in Montana that investigators would look at icing on the wings as a factor. "We will be looking at everything as it relates to the weather," he said.

The single-engine Pilatus PC 12/45, designed to carry 10 people, crashed 500 feet short of the Montana airport runway, nose-diving into a cemetery and killing seven adults and seven children aboard. Relatives said the victims had been headed to an exclusive resort on a ski vacation, and said the children were 1 to 9 years old.

Irving "Bud" Feldkamp, a dentist and president of Glen Helen Raceway in Southern California, said two of his daughters, two sons-in-law, and five of his grandchildren were among the victims.

They had all planned to meet for a weeklong vacation at the millionaires-only Yellowstone Club south of Bozeman, Mont.

Bob Ching, who was to have hosted the Feldkamps, lost his son and daughter-in-law and their two children.

The pilot was identified as Buddy Summerfield, 65, of Redlands, Calif.

Experts said finding the cause of the crash was likely to be significantly complicated by the absence of either a cockpit voice recorder or a flight data recorder, which is not required for smaller aircraft that do not fly commercial passengers.

Hours after the crash, federal investigators had focused on overloading as a possible cause.

"It will take us a while to understand," Rosenker said. "We have to get the weights of all the passengers, we have to get the weight of the fuel, all of the luggage."

Standard flight procedures are for the pilot to file a report on the plane's weight and how that weight would be distributed on the plane, safety experts said.

Peter Felsch, a meteorologist at the National Weather Service, said conditions measured on the ground not long after the 2:30 p.m. crash were fair - winds of about 9 m.p.h., 10 miles visibility, a temperature of 44 degrees Fahrenheit, and a "broken cloud deck at 6,500 feet." The Pilatus PC is certified for flight into known icing conditions, according to the manufacturers' Web site and pilots who have flown the plane.

However, like all turboprops, it relies on deicing boots - strips of rubberlike material on the leading edge of the wings and the horizontal part of the tail - that inflate and contract to break up ice. That technology is not as effective at eliminating ice as the heat that jetliners divert from their engines to their wings.

One key in the Butte crash will be whether the pilot had changed the position of the aircraft's wing flaps for landing because changing the configuration of the wings by moving the flaps is where icing problems often show up.

There won't be any radar data of the plane's final moments for investigators to examine; like thousands of small airports, the Butte airport does not have a radar facility.

Wind shear may have caused the crash of a FedEx jet that cartwheeled on the runway at Tokyo's Narita International Airport and burst into a fireball, investigators said yesterday, but experts noted that the model was notoriously difficult to land.

The American pilots - the only two people on board - were killed when the MD-11 cargo plane coming in from Guangzhou,

China, bounced on its landing, slammed onto

the runway, and tipped

on its side before exploding into flames.

Kazuhito Tanakajima, an aviation safety official at Japan's Transport Ministry, said the crash may have been a result of "wind shear," sudden changes in wind that can lift or smash a plane into the ground during landing.

Tomoki Kuwano, a former Japan Airlines pilot, said the MD-11 can be hard to land. In 1999, an MD-11 flipped over and burst into flames, killing three people during a crash landing in

a storm in Hong Kong. In 1997, one landed hard, flipped, and caught fire in Newark, N.J.

The FedEx pilots were identified as Kevin Kyle Mosley, 54, of Oregon,

and Anthony Stephen Pino, 49, of Texas.

- Associated Press

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