Investigators said Tuesday they were looking into whether ice on the wings or a mechanical problem contributed to the fiery crash of an executive jet that killed the 14-year-old son of NBC Sports chairman Dick Ebersol (search) and two others.

National Transportation Safety Board (search) investigator Arnold Scott said the plane had not been de-iced before its attempted takeoff Sunday morning in light snow, fog and freezing temperatures outside this soilled when he was ejected from the plane and crushed by the wreckage.

The pilot, 50-year-old Luis Alberto Polanco of the Dominican Republic, and flight attendant Warren T. Richardson III, 36, of Coral Gables, Fla., also were thrown from the plane and died from the impact, Young said. The Federal Aviation Administration (search) will conduct toxicology tests, he said.

Ebersol and his oldest son Charlie, 21, remained hospitalized but are expected to recover, NBC said. The network's Denver affiliate, KUSA-TV, reported that Dick Ebersol suffered broken ribs, a broken sternum and had fluid in his lungs, while Charlie suffered a broken hand and had a sore back.

The co-pilot, identified by Denver newspapers as Eric Wicksell of Daytona Beach, Fla., was in critical condition at a burn unit in Denver.

Investigators found Edward's body under the wreckage Monday. He was the youngest son of Ebersol, 57, and his wife, "Kate and Allie" star Susan Saint James.

Saint James and the middle Ebersol son, 18-year-old Willie, were not on the flight.

"We will miss Teddy, our sweet boy, forever," the Ebersols said in a statement.

"While our grief is unfathomable, we are so proud of our Charlie, who pulled his father from the flames. That anyone was able to survive this horrible accident is a miracle, and all of us will forever be inspired by Charlie's courage and bravery," the statement said.

Jet Alliance of Millville, N.J., whose sister company, Air Castle Corp., operated the charter flight, said Polanco was a 20-year pilot with more than 12,000 hours of flying time, including 900 hours in the type of plane that crashed, a Canadair CL-601 Challenger.