( CNN ) -- A commuter airliner that crashed Thursday in upstate New York , killing 50 people , underwent violent pitching and rolling seconds before impact , with passengers experiencing twice the normal force of gravity , a federal investigator said Sunday . Only a few pieces of the Continental Connection Dash 8 turboprop were recognizable after the crash . The plane 's final 800-foot fall took five seconds , Steve Chealander of the National Transportation Safety Board said . The aircraft crashed into a home in Clarence Center , New York , near Buffalo , on Thursday night , killing all 49 people aboard . A 61-year-old man in the house died also , but his wife and daughter survived . Final motions of the aircraft were so drastic that the plane 's autopilot automatically disengaged and warnings sounded , Chealander said , citing information from the plane 's flight data and cockpit voice recorders . Also , a `` stick-shaker '' device , which noisily vibrates an airplane 's controls to warn the pilot of imminent stall , kicked in , he said . The flight crew of Continental Connection Flight 3407 , operated by Colgan Air , discussed `` significant '' ice buildup on the aircraft 's windshield and wings before the crash , and icing has become a focus as a possible cause . Follow the plane 's path » . Chealander said the plane 's de-icing system was turned on 11 minutes after the flight left Newark , New Jersey , for Buffalo , and remained on for the entire flight . He said the pilots were told before departure from Newark that there was `` light to moderate icing '' in the Buffalo area but that no other pilots had reported problems with their landings at the Buffalo airport . `` It was really not a bad-weather day , and they chose to launch [ from Newark ] , '' Chealander said of the pilot and the first officer . The plane was on autopilot during its approach to the Buffalo airport , Chealander said . As to questions about whether the autopilot should have been turned off , Chealander said using it even in bad weather situations `` is normal . '' Watch Chealander discuss autopilot options » . `` You 're encouraged to use the autopilot to help you with the workloads of these high intense weather situations that we fly into all the time , '' he said . He said the NTSB in the past has recommended to the Federal Aviation Administration , which oversees civil aviation including commercial airlines , that in severe icing conditions , `` it might be best to disconnect autopilot so that the pilot might have a better feel '' for the aircraft 's conditions . However , severe icing is `` not what we saw here , '' Chealander said , adding that the FAA has no such disengagement rule in effect . `` To say that they should not have been flying on autopilot is not correct , '' Chealander said . The pilots ' recorded remarks about `` significant '' icing did not indicate `` severe '' icing , he said . The NTSB has said problems for the 74-seat Bombardier Dash 8 Q400 occurred when the pilots lowered the landing gear and tried to set the wing flaps to slow the aircraft for landing . Offering more details , Chealander said Sunday that the plane 's nose pitched up 31 degrees , then down 45 degrees . The aircraft rolled left 46 degrees then right 105 degrees , or past the 90-degree vertical point , he said . Inside the cabin , he said , conditions went from lower than normal gravitational force to twice the normal force as the plane rocked through the sky . iReport.com : Send your photos , videos from the scene . Chealander said the NTSB 's investigation of the crash site indicated that the two propellers on the turboprop aircraft were in place when the crash occurred . `` The airplane had n't lost anything prior to impact . It came down intact , '' he said . Meanwhile , local authorities working to recover remains of the victims said Sunday that a federal team of more than 40 people using some $ 2.8 million worth of scientific equipment would begin on Monday to help establish positive identification of the victims . But because of the intensity of the crash and a subsequent fire , `` whether we can identify everybody or not remains to be seen , '' Erie County Health Commission Anthony Billittier said . Authorities had recovered 15 bodies as of Saturday night , but Billittier announced Sunday that numbers of recovered bodies will no longer be released `` out of respect for the families . ''
NTSB : The National Transportation Safety Board (NTSB) has released a preliminary report on the crash of Asiana Airlines Flight 214 in San Francisco last month. Plane rolled past the vertical point before it crashed into home , NTSB official says . Thursday 's crash in upstate New York killed all 49 aboard plane , one in house . Plane 's de-icing system was turned on 11 minutes after takeoff , NTSB says .