it merely changes the area where the aircraft ended. >> you said it still makes you believe there was something mechanical. explain that. i believe that one possible scenario that makes sense for all the day that that we have found would be a fire in the electronics bay that would have caused the failure of the equipment. it would start with the failures of the acars and transponder. possibly vhf radios that would have precluded the pilots from communicating that would have caused smoke in the cockpit. this is the only area of the aircraft that is not monitored for fire alert, unlike the cargo holds. they would have fire warnings. in this case, they wouldn't. they would not have a fire