Updated

Divers were hoping to zero in on AirAsia Flight 8501's black boxes Thursday, after search and recovery operations got a much-needed boost with the discovery of a chunk of the plane's tail -- nearly two weeks after it plummeted into the sea, killing everyone onboard.

The flight and cockpit voice recorders, which are crucial to helping determine what caused the jet to go down, are located in the rear section of the aircraft.

Divers and at least six ships equipped with underwater detectors were working in the area where an unmanned underwater vehicle spotted the tail Wednesday -- the 10th day of hunting, said Suryadi B. Surpiyadi, a search and rescue operation coordinator from Pangkalan Bun, the closest town to the site.

The wreckage was found upside down and partially buried in the sea floor about 6 miles from where the Airbus A320 carrying 162 passengers and crew lost contact with the control tower on Dec. 28. The plane was nearly halfway between the Indonesian city of Surabaya and Singapore.

The registration number, PK-AXC, and part of the AirAsia logo proved it was the plane, Surpiyadi said.

Divers on Thursday were unable to make progress. The water in the Java Sea is relatively shallow at about 100 feet deep, but this is the worst time of year for a recovery operation with monsoon rains and wind creating choppy seas and blinding silt from river runoff.

"Their mission was to check on whether the black boxes are still in their positions or have been loosened," National Search and Rescue chief Henry Bambang Soelistyo said. "But strong current and less than 1 meter of visibility hampered their efforts."

He said that expert teams from Indonesia and France were looking for a technique on how to find and lift the black boxes from the plane's tail.

Tony Fernandes, AirAsia's chief executive officer, tweeted Wednesday that black boxes should be in the tail.

He said that the airline's priority is still is to recover all the bodies "to ease the pain of our families."

The carrier, meanwhile, said families of those killed would be compensated in accordance with Indonesian laws. Each will receive $100,000, Sunu Widyatmoko, president of AirAsia Indonesia, told reporters in Surabaya.

So far, 40 corpses have been found. Officials are hopeful many of the 122 bodies still unaccounted for will be found inside the fuselage, which is thought to be lying near the tail.

Bad weather is believed to be a contributing factor to the crash.

Just before losing contact, the pilot told air traffic control he was approaching threatening clouds, but was denied permission to climb to a higher altitude because of heavy air traffic. No distress signal was issued.

Finding the black boxes will be key to the investigation. They provide essential information about the plane along with final conversations between the captain and co-pilot. The ping-emitting beacons still have about 20 days before their batteries go dead, but high waves had prevented the deployment of ships that drag ping locators.