PANGKALAN BUN: Investigators searching for black boxes in the crashed AirAsia plane lifted the tail portion out of the Java Sea on Saturday, after it went down two weeks ago, 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 Dec. 28.

Their recovery is essential to finding out why it crashed.

The tail was hoisted from a depth of about 30 meters (100 feet) 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 Friday about a kilometer (half 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.

Read: AirAsia jet tail found underwater, black box may be close

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.

Also read: Search expands for missing AirAsia passenger jet

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 to 38,000 feet to avoid threatening clouds, but were denied permission because of heavy air traffic above them.

Four minutes later, the plane dropped off the radar.

Also read: Some AirAsia victims found belted in seats

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 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.

Meanwhile, Transportation Minister Ignasius Jonan cracked down on five airlines Friday, temporarily suspending 61 flights, because they were flying routes on days without permits.

Earlier, all AirAsia flights from Surabaya to Singapore, the path Flight 8501 was on when it went down Dec. 28, were suspended after it was discovered that the low-cost carrier was not authorised to fly on Sundays.

Transportation Minister Ignasius Jonan also sanctioned nine more officials for allowing the plane to fly without permits, bringing the total to 16.