Might I just ask, and excuse me in advance of any ignorance on this subject, but given that after two years sitting on the bottom of the South Atlantic ocean under immense pressure, both the flight data and cockpit voice recorders from the Air France disaster have been found intact and more amazing still is that they were found at all given the size of the wreckage area, why then have the black boxes from the aircraft that smashed into the twin towers not been found and never will be found?