Jakarta - Investigators searching for black boxes in the crashed AirAsia plane lifted the tail portion out of the Java Sea on Saturday, two weeks ago after it went down, killing all 162 people on board.It was not immediately clear if the cockpit voice and flight data recorders were still inside the tail or have been detached when the Airbus A320 plummeted into the sea on 28 December. Their recovery is essential to finding out why it crashed.The tail was hoisted from a depth of about 30 metres using inflatable bags that were attached to the rear of the aircraft and a crane to lift it onto a rescue ship.Intermittent underwater ping-like sounds were picked up on Friday about a kilometre from where the tail was located, but it was unclear if they were coming from the recorders located in the back of the aircraft. It was possible the signals were coming from another source.No metal was detected at the ping location, and Nurcahyo Utomo, a National Commission for Transportation Safety investigator, said the sounds could not be confirmed.Breakthrough The discovery of the tail on the ocean floor earlier this week was a major breakthrough in the slow-moving search that has been hampered by seasonal rains, choppy seas and blinding silt from river runoff. Officials were hopeful the black boxes were still inside.The last contact the pilots had with air traffic control, about halfway into their two-hour journey, indicated they were entering stormy weather. They asked to climb from 32 000 feet (9 753 metres) to 38 000 feet (11 582 metres) to avoid threatening clouds, but were denied permission because of heavy air traffic above them. Four minutes later, the plane dropped off the radar.Four additional bodies were recovered on Friday - two of them still strapped in their seats on the ocean floor - bringing the total to 48. Officials hope many of the remaining corpses will be found inside the fuselage, which has not yet been located by divers. Several large objects have been spotted in the area by sonar.