Search teams hunting for the wreck of AirAsia flight QZ8501 are focusing their efforts on four large objects found on the seabed off the coast of Borneo, as the search for bodies continues.

The Indonesia AirAsia airbus A320-200 plunged into the Java Sea on Sunday while en route from Indonesia’s second-biggest city Surabaya to Singapore.

Of the 162 passengers on board the plane, no survivors have been found.

A multi-national task force of ships, planes and helicopters have been scouring the northern Java Sea and coastline of southern Borneo to recover the bodies of victims and locate the wreck and its black box flight recorders.

“We’ve found four big parts from the plane we’re looking for,” search and rescue agency chief Fransiskus Bambang Soelistyo told reporters in Jakarta.

Recovery teams found two big parts of the AirAsia plane in the Java Sea off the island of Borneo late on Friday night.

Mr Soelistyo said another two sections, the largest of which was around 18 metres long, were located on Saturday.

Another official, Supriyadi, who is coordinating the operation from the port of Pangkalan Bun in Borneo, said earlier that poor visibility had hampered efforts to capture images of the objects with underwater remote operating vehicles (ROVs).

“The visibility is only two metres,” he said. “It’s cloudy, making it difficult for the cameras to detect.”

Divers, including a team of Russian specialists who just arrived in Pangkalan Bun, may be able to investigate the suspected wreckage on Sunday if the weather improves, officials said.

No survivors found as search continues

No survivors have been found from the crash, which happened about 40 minutes after the plane took off from Indonesia’s second largest city in an area known for intense tropical thunderstorms during the monsoon season.

Thirty bodies have been recovered from the sea, although rescue official Supriyadi said it was unlikely more would be found floating.

“Because we’re already in the seventh day … the chances are they have all sunk,” he said.

“There’s a possibility they’ll be found on beaches.”

Experts believe most of the bodies will be found inside the plane’s fuselage.

Small pieces of the aircraft and other debris have also been found, but there has been no sign of the crucial voice and flight data recorders that investigators hope will unravel the sequence of events in the cockpit during the jet’s final minutes.

The cause of the crash, the first fatal accident suffered by the AirAsia group, remains unexplained.

The plane was flying at 32,000 ft and the pilot had asked to climb to 38,000 ft just before contact was lost.

When air traffic controllers granted permission to fly at 34,000 ft a few minutes later, there was no response.

A source close to the investigation said radar data appeared to show the aircraft made an “unbelievably” steep climb before it crashed, possibly pushing it beyond the A320’s limits.

A report from Indonesia’s weather bureau said it was likely the plane had flown into bad weather which would have been difficult to avoid, and that it was possible this had caused ice to form on its engines.

“Based on the available data on the last received location of the aircraft, the weather was a factor in causing the accident,” the weather bureau said.

Plane was flying on ‘unauthorised schedule’

Meanwhile, Indonesia’s transport ministry said the AirAsia plane was flying on an unauthorised schedule when it crashed, adding it had now frozen the airline’s permission to fly the route.

The transport ministry said AirAsia was not permitted to fly the Surabaya-Singapore route on Sundays and had not asked to change its schedule.

“It violated the route permit given, the schedule given, that’s the problem,” said Djoko Murjatmodjo, the director general of air transport.

“AirAsia’s permit for the route has been frozen because it violated the route permit given.”

He later added: “We are going to investigate all AirAsia flight schedules.

“Hopefully we can start on Monday. We won’t focus on licences, just schedules.

“It might be possible to revoke AirAsia’s licence in Indonesia.”

Indonesia AirAsia chief executive Sunu Widyatmoko said the company would cooperate with the government investigation but declined to elaborate.