is that how it happened? >> that's right. when they took the engines apart and inspected them that's what happened. they -- the glass on the blades obstructed the air flow. >> could you see the cloud? >> no we were flying at night so there was no moon, no visual reference. you could probably see it in daylight but it was night. probably a lot of people are now aware, aircraft weather radar systems we have onboard are not designed to pick up the ash clouds. >> shepard: they pick up water. >> water and suspension and the ash clouds that we see forms a silica, like glass. >> shepard: you're flying along, i'm guessing on autopilot and all of a sudden what happens?