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 with the deaths of all 162 people on board.

It was not immediately clear if the cockpit voice and flight data recorders were still inside the tail or had 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 (100 feet) using inflatable bags that were attached to the rear of the aircraft, and then a crane to lift it on to a rescue ship.

Intermittent underwater ping-like sounds were picked up on Friday about half a mile 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 from another source.

No metal was detected at the ping location and Nurcahyo Utomo, an investigator with Indonesia’s transportation safety authority, said the sounds could not be confirmed.

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 silt from river runoff clouding the water. 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 Friday — two of them still strapped in their seats on the ocean floor — bringing the total to 48. Officials hope the rest will be found inside the fuselage, which has not yet been located by divers. Several large objects have been picked up on sonar.

Indonesia’s transportation minister, Ignasius Jonan, cracked down on five airlines on Friday, temporarily suspending 61 flights, because they were flying routes on certain days without permits. Earlier all AirAsia flights from Surabaya to Singapore, the path flight 8501 was taking when it went down on 28 December, were suspended after it was discovered that the low-cost carrier was not authorised to fly on Sundays. Jonan also sanctioned nine more officials for allowing the plane to fly without permits, bringing the total to 16.