on the table and that's credible. the original turn-back was towards the closest available airport, so that makes sense. so the initial part actually makes sense, some sort of catastrophic problem. >> when you say catastrophic, you don't mean instantaneous, you mean mechanical issues on board that the pilot had time to try to make that turn to try to find the closest airport. >> sure. yeah, some sort of progressive problem like smoke in the cockpit if you had an electrical fire in the avionics bay or something like that, he would have turned to the nearest airport which would have made sense. under that hypothesis if they became incapacitated or if there was a flight control problem. if there was a flight control problem, they still would have had the radio, so it's hard to figure out. what really doesn't make sense on that, though, was if they did become incapacitated and the airplane was flying along, it would normally continue in the direction it was going because it would have been programmed either in the flight management computer or just in heading hold