CLARENCE, N.Y. (AP) — Crash investigators picked through incinerated wreckage Saturday, gathering evidence to determine what brought down a commuter plane that plunged into a home and exploded.

It could take days to recover all human remains from the plot of land where a single-family home stood before Continental Connection Flight 3407 nose-dived into it late Thursday, National Transportation Safety Board spokesman Steve Chealander said.

Experts were analyzing data from the black boxes, including statements by crew members about a buildup of ice on the wings and windshield of the plane, Chealander said.

But authorities have yet to pin that as the cause of the crash, which occurred during a light snow and mist, killing 49 people on the flight and one man in the home.

Ice on wings can cripple an aircraft and has been blamed for several previous plane crashes. Other aircraft in the area Thursday night told air traffic controllers it also experienced icing around the time that Flight 3407 from Newark, N.J., to Buffalo went down.

Icing is one of several elements being examined by investigators, who plan to remain in Buffalo for another week before shipping plane parts to locations around the country for study, Chealander said. A full report will likely take a year, he said.

"We're in the very early stages of the investigation," he said. "The icing and other things are just preliminary focuses."

One aspect of the investigation will focus on the crew, how they were trained and whether they had enough time to rest between flights. Other investigators focused on the weather, the mechanics of the plane and whether the engine, wings and various mechanics of the plane operated as they were designed to.

But recovery of the bodies will take priority over the investigation, Chealander said.

The remains-recovery effort was being led by Dennis Dirkmaat, a forensic anthropologist from Mercyhurst College in Erie, Pa., and a nationally renowned expert who led the recovery effort after United Flight 93 crashed in Shanksville, Pa., on Sept. 11, 2001.

The crash site remained off limits Saturday, with police barring reporters and photographers from the neighborhood.

Authorities still haven't released a list of the victims of the nation's first deadly air crash in 2½ years, but reminders of the disaster were visible all around the Buffalo area.

Flags flew at half-staff outside Buffalo Niagara International Airport and at Clarence Town Hall, the site of a command center set up by police.

Family members of the victims were sequestered in a hotel Saturday where they were scheduled to meet with representatives of Continental Airlines. Police turned away reporters.

The 74-seat Q400 Bombardier aircraft was operated by Colgan Air, based in Manassas, Va. Colgan's parent company is Pinnacle Airlines of Memphis, Tenn.


Associated Press writers Carolyn Thompson, William Kates and Larry Neumeister contributed to this report.