MISSING MALAYSIAN AIRLINER

Malaysia Airlines Flight 370 flew north of Indonesia and around Indonesian airspace in its journey to the southern Indian Ocean, a senior Malaysian government source told CNN.

The conclusion was reached by investigators after reviewing radar track data from neighboring countries.

The plane did not fly over Indonesia or its airspace after making a westward turn in the South China Sea and flying across the Malaysian Peninsula, the source said.

According to the source, the plane may have purposely been flown along a route designed to avoid radar detection.

[Original story, posted at 2:22 a.m. Sunday]

Flight 370: Search teams investigate sounds picked up in ocean

(CNN) -- Search teams looking for Malaysia Airlines Flight 370 are investigating a number of sounds detected by ships in the southern Indian Ocean, authorities said Sunday, but it's not yet clear if any of them are from the missing plane's so-called black box.

A British Royal Navy vessel is on its way to an area where a Chinese ship reported picking up electronic signals twice, once on Friday and again on Saturday, said Angus Houston, the head of the Australian agency coordinating search operations.

And the Australian naval ship Ocean Shield, which has highly sophisticated equipment, is pursuing "an acoustic noise" that it detected in a different area, Houston said at a news conference.

He said the detections were "an important and encouraging lead," but he cautioned that they be treated "carefully" as they haven't been verified as being related to Flight 370.

Fevered search

Searchers are desperately seeking any clue about the location of the airliner that disappeared nearly a month ago with 239 people on board.

Up to 10 military planes, two civil aircraft and 13 ships will assist in Sunday's search for the airline. The Australian Maritime Safety Authority (AMSA) plans to search three separate areas Sunday about 2,000 kilometers (about 1,240 miles) northwest of Perth. That area totals about 216,000 square kilometers (83,000 square miles).

Australian planes are being deployed to the area where the Chinese ship, Haixun 01, picked up signals that would be consistent with those emitted by an aircraft's flight recorders, said Houston, the chief coordinator of Australia's Joint Agency Coordination Centre.

A number of white objects were sighted about 56 miles (90 kilometers) away from where the sound was detected, he said.

But he stressed that were was so far no confirmation that the signals and objects are related to Flight 370.

"In the days, weeks and possibly months ahead, there may be leads such as the one I'm reporting to you this morning on a regular basis," Houston, a retired air chief marshal, said.

Handheld hydrophone

Video on Chinese state-run CCTV shot Saturday shows crew members from the Haixun 01 boarding a small yellow dinghy and using what appears to be a handheld hydrophone. The three men on board lower the device into the water on a pole.

The handheld ping-locating technology used by the Chinese ship is not as versatile as a U.S. Navy towed locator, which goes as deep as 20,000 feet, far from surface noise, according to experts.

The U.S. Navy hydrophone -- or underwater microphone, is on board the Australian ship Ocean Shield, which recently joined the search for Flight 370.