The National Transportation Safety Board said that NYC investment banker Jeffrey Buckalew told air traffic control that his small plane was icing up after taking off from Teterboro Airport on Tuesday. The Socata TBM-700 crashed onto 287 in Harding, NJ, killing Buckalew, his wife Corinne, their two children Jackson and Meriwther, as well as Buckalew's colleague Rakesh Chawla.

Earlier, the NTSB had said that Buckalew, who had been a pilot for about a decade, had mentioned icing, but it was unclear whether his plane was experiencing it, just that he tried to ascend to a higher altitude to avoid it. Yesterday NTSB investigator Ralph Hicks said it was too soon to draw a conclusion about the cause of the crash, but did add, "The pilot confirmed he was picking up ice. How much ice was on the plane, we don’t know, and we might never know."

The Star-Ledger reports. "At least one other pilot in the area, at the controls of a commercial jet, radioed in to report severe icing between 14,000 feet and 17,500 feet, Hicks said. Buckalew had reached about 18,000 feet when radar contact was lost. Shortly after 10 a.m., about 14 minutes after takeoff from Teterboro Airport, the plane barreled earthward in an uncontrolled spiral, shedding pieces before slamming into Interstate 287 in Morris Township, witnesses said."

The plane’s response to the icy conditions is certain to play a central role in the probe. Hicks said the Socata had a wing de-icing system — pneumatic "boots" that rapidly inflate and break up any ice that forms — but it was unclear if the system was in operation at the time.

Aviation experts say icing can develop suddenly as "supercooled" droplets of water in the air smack into a moving object and freeze instantly. Such icing might cause an engine to fail or an instrument to read inaccurately. It also might interfere with the aerodynamics of a plane, causing it to dive.

"What the wings do is produce lift," said Ken Paskar, a longtime pilot and aviation consultant based in New York City. "When ice develops on a wing, it changes the shape of the wing, airflow becomes disturbed, and you lose lift."

Witnesses said they heard explosions before the plane crashed and that pieces were falling from the plane before impact. One said, "“It was kind of rolling and making circles — ’cause I’ve seen air shows before — so I thought: ‘Oh, OK;’ but then he finally did a nosedive and we realized that was completely wrong."

Buckalew and Chawla were managing directors at investment bank Greenhill and Co. They were headed to a meeting in Atlanta, and then Buckalew and his family (their dog was also on the plane) were going to their Charlottesville, Virginia home—Buckalew lived in their Upper East Side apartment during the work week and then commuted to Charlottesvile for the weekends— for the holidays. Chawla, the father of three, was due to take a commercial flight back to NYC that night.