sometimes it's just the warning signals on there. but in this case, in an accident scenario, they don't have everyone still alive and able to tell them what happened. they are fortunate here for that. you're listening for things that might not otherwise be captured in the investigation phase. this has been a sore point for some time with the united states national transportation safety board because european countries do require that to be 25 hours on newer plane models and in the united states it's two hours. >> i'm surprised every time i hear this data. one would think if a door or part of a plane blows off, for whatever reason, one would override however many windows you want to have that data and recording preserved.