wait a minute, they're not going to beijing anymore? >> if they entered the change and entered it in and started acting on the change they should know it if acars was still working, sure. >> right. so keith, what is your prevalent theory? the one that everybody came back around to today was some sort of catastrophic smoke in the cockpit. maybe a tire fire so the pilots put on their masks, they're pulling circuit breakers, i guess, to try to isolate where this electrical fire is coming from which then cascades, shuts down the transponder and the radios. go. what do you think of that? >> well, i think that's a little bit far fetched. certainly based on the last radio communication that was received, it didn't seem like they were in any sort of distress. when you put on the oxygen mask and then attempt to talk on the radio, there's a significant change in the audio quality because you're talking through a mask rather than through the air