41.   Acoustic beacons placed on the ocean floor will transmit signals to hydrophones mounted on the hull of the rig.

42.   Al Dickinson, NTSB chief site investigator, said the search began concentrating more heavily on sonar mapping of the ocean floor Sunday afternoon.

43.   But as it was raised from the ocean floor, the fuselage broke in two.

44.   But as more pieces of the wreckage were pulled from the ocean floor, they retreated from that theory.

45.   But from the ocean floor to the shelf of the neighborhood hardware store remains a bit of a leap.

46.   But it was not clear whether that evidence was recovered from the ocean floor in recent days.

47.   But Moscow lacked the underwater technology to investigate the ocean floor for her dead.

48.   But the real booty, Rea hopes, is still resting on the ocean floor.

49.   But they cannot be sure whether mechanical problems or pilot error was to blame until the plane is raised from the ocean floor.

50.   Concrete mooring platforms were placed on the ocean floor to secure a Canadian vessel as a diving platform.