believe. it might have a lot to do with icing or hail or an updraft or some sort of wind shear or some combination of all of those. it's important to remember when you look at just about any accident you can imagine it's always a series of things that leads to the accident. and any one item in that series that chain, you pull one link out and you usually don't have the accident. so we have to look at the whole big picture here. >> all right, miles o'brien and john noble, thanks to you both. still to come breaking right now, a date has now been set for opening arguments, or opening statements in the trial of accused boston marathon bomber dzhokhar tsarnaev. we'll go live to the courthouse for the latest. plus, the one issue that kept the defense and the government from reaching a plea deal. we are live in boston as jury selection begins this morning.