Federal safety investigators said Wednesday the flight data recorder from last month's air crash near Buffalo, N.Y., shows the plane's stall warning system had activated before the accident and that there were no mechanical problems found with the plane.

All 49 people aboard the plane and one man in the house died.

The National Transportation Safety Board said in a statement Wednesday the data "shows that some ice accumulation was likely present on the airplane prior to the initial upset event, but that the airplane continued to respond as expected to flight control inputs throughout the accident flight."

Click here for photos of some of the victims.

Click here for photos of the crash.

9/11 Widow Killed in Continental Plane Crash in Buffalo

Former NTSB investigator Greg Phillips said it appears so far that the ice "wasn't anything the plane shouldn't have been able to handle."

Investigators are continuing to examine the Dash 8-Q400 Bombardier's deicing system and to probe the flight crew's training, the statement said.

The board has scheduled a three day public hearing for May 12 to 14 on the crash. The hearing will cover a range of safety issues, including the icing effect on the airplane's performance, cold weather operations, sterile cockpit rules, crew experience, fatigue management, and stall recovery training, the statement said.

"The tragedy of flight 3407 is the deadliest transportation accident in the United States in more than seven years," acting NTSB Chairman Mark Rosenker said in the statement. "The circumstances of the crash have raised several issues that go well beyond the widely discussed matter of airframe icing, and we will explore these issues in our investigative fact-finding hearing."

Continental Connection Flight 3407 was about five miles short of the Buffalo Niagara International Airport flying in icing conditions the night of Feb. 12 when the plane tumbled wildly out of control and plummeted onto a house.