the last known communication with the plane with radar was as it was heading north over the strait gt of malacca. the last ping was about 7 hours in to the flight. that puts it somewhere on a very big arc. after initially saying the plane's last acars system was turned off before the last cockpit call suggesting pilot involvement, malaysian officials are thousand saying they have no idea when the acars system was actually turned off. they have searched the co-pilot's and pilot the's houses focusing on a flight simulator the pilot owned, but so far they have not turned up any clues. >> still looking. thank you. at this hour, vice president biden is on his way to ukraine's back door. he's visiting poland and lithuania as that tug of war