Relying mostly on analysis of data from the Inmarsat satellite with which the aircraft last communicated Communication , the Australian Transport Safety Bureau proposed initially that a hypoxia event was the most likely cause given Giving the available evidence , although there has not been any consensus concerning this theory among investigators Criminal_investigation .

A subsequent investigation Criminal_investigation concluded Coming_to_believe that the pilot and passengers had become Becoming incapacitated and had been suffering Bodily_harm from hypoxia Hindering , a lack of oxygen to the body , meaning Causation the pilot would have been unable to operate Control the aircraft .