Indonesian officials say the black box of AirAsia flight QZ8501 may be buried in the seabed, or muddy waters may be impeding its signal.
Nine days after the plane crashed, officials said there was still no sign of the crucial black box flight recorders.
Search and rescue agency official Supriyadi, who is co-ordinating the operation from the southern Borneo town of Pangkalan Bun, said there had been no "pings" detected from the black box's emergency locator beacon.
He said it was possible it was buried in the seabed or the muddy water was impeding its signal.
"They haven't found anything, maybe because the water is turbid and there is zero visibility," Supriyadi said.
"There's a possibility it is buried in mud."
Divers use good weather to try to reach wreckage
Search teams - including divers - took advantage of a let-up in bad weather to try to reach the wreckage of the AirAsia jet, yesterday.
"Today's weather is friendly, the team can work," the head of Indonesia's search and rescue agency, Fransiskus Bambang Soelistyo, told a news conference in Jakarta.
Mr Soelistyo said the multinational air and sea operation had two objectives; to recover bodies and wreckage floating in an ever-widening search area in the northern Java Sea, and to find wreckage and the plane's black box on the ocean floor.
The latter effort is focused on an area about 90 nautical miles off Borneo, where ships using sonar have located five large objects believed to be parts of the plane - the largest about 18 metres long - in shallow water.
Indonesian officials believe they may have located the tail and parts of the fuselage of AirAsia flight QZ8501 at the bottom of the Java Sea but strong currents, high winds and big waves have hindered attempts to investigate the debris.
On Monday the captain of an Indonesian navy patrol vessel said his ship found what was believed to be the plane's tail.
If confirmed the discovery would be a key find since that section of the aircraft houses the cockpit voice and flight data recorders.
But Mr Soelistyo said it could not be confirmed the finding was indeed the plane's tail.
Flight QZ8501 plunged into the water off Borneo island on December 28, about 40 minutes into a two-hour flight from Indonesia's second-biggest city of Surabaya, en route to Singapore.
There were no survivors among the 162 people on board.
Only 37 bodies of the mostly Indonesian passengers and crew have been recovered. Many more could still be trapped in the fuselage of the aircraft.