mechanical failure, fire on board, for instance, which gradually shut down systems or the pilots felt like they had to shut down systems, correct? >> anything is up for grabs at this point. we can go back to twa 800 where it was attributed to fuel pumps in one of the tanks, because of dry tanks to ignited the vapors. that could be a possible scenario. i very much doubt it because these airplanes have been modified so that never occurs. but, you know, when we talk about catastrophic failure, it progressively might have turned into that where they were trying to troubleshoot the system. if this started to slowly degrade all the avionics and internal communication system and flight controls things would get haywire. there's an electronic checklist that's a tremendous system that we utilize with a touchpad screen to go through an abnormal situation. if they were trying to find this and that screen went blank, now they have to refer to a standard, let's call it a paper checklist.