Updated | Missing AirAsia aircraft probably 'at bottom of sea'

The AirAsia plane that went missing with 162 people on board after takeoff from Indonesia is likely at the bottom of the sea, Indonesia's National Search and Rescue Agency chief said as aircraft and ships were dispatched to search for the jet.

"Based on the coordinates given to us and evaluation that the estimated crash position is in the sea, the hypothesis is the plane is at the bottom of the sea," Bambang Soelistyo told reporters on Monday.

The search for the Airbus A320-200, which disappeared with 162 people on board on Sunday on a flight to Singapore, has ended for a second day.

The search area will be widened on Tuesday.

"That's the preliminary suspicion and it can develop based on the evaluation of the result of our search."

First Admiral Sigit Setiayana, the Naval Aviation Center Commander at the Surabaya air force base, said that 12 navy ships, five planes, three helicopters and a number of warships were searching an area of east and southeast of Indonesia's Belitung island and nearby waters.

Malaysia and Singapore have joined the operation while Australia deployed sophisticated surveillance aircrafts over the in the multinational search in the Java Sea.

The Airbus A320-200 went missing after air traffic controllers lost contact with the aircraft about 45 minutes after it left Juanda international airport at Surabaya in East Java at 5:20am on Sunday (22:20 GMT Saturday).

The flight path of the AirAsia jet which went missing

Shortly before disappearing, AirAsia said pilots of the plane had asked permission from Jakarta air traffic control to change course and climb above bad weather in an area noted for severe thunderstorms.

The aircraft was operated by AirAsia Indonesia, a unit of Malaysian-based AirAsia which dominates Southeast Asia's booming low-cost airline market. 

AirAsia said the missing jet last underwent maintenance on November 16. The company has never suffered a fatal accident.

An official from Indonesia's Transport Ministry said the pilot asked to ascend by 6,000 feet to 38,000 feet to avoid heavy clouds.

"The plane is in good condition but the weather is not so good," Djoko Murjatmodjo told a press conference at Jakarta's airport, addressing reports of severe storms in the area where the jet went missing.

Climbing to dodge large rain clouds is a standard procedure for aircraft in these conditions.

The plane's disappearance comes at the end of a disastrous year for Malaysian aviation.

Malaysia Airlines Flight MH370, carrying 239 people, vanished in March after inexplicably diverting from its Kuala Lumpur-Beijing course. No trace of it has been found.

Another Malaysia Airlines plane went down in July in rebellion-torn eastern Ukraine, killing all 298 aboard. It was believed to have been hit by a surface-to-air missile.