PERTH, Australia - A US Navy "black box" detector made its much-anticipated debut in the oceanic hunt for flight MH370 on Friday but Australia's search chief warned it was crunch time with the box's signal set to expire soon.
As the extensive search wore on, Malaysian opposition leader Anwar Ibrahim said he believed the country's long-ruling regime was concealing information on the crisis, saying "the government knows more than us."
The Australian naval vessel Ocean Shield arrived with a "towed pinger locator" capable of homing in on signals from the black box, as 14 planes scoured the remote Indian Ocean search area for signs of a crash site.
The plane disappeared March 8, and Australian authorities coordinating the search have rushed the device into place with the black box's roughly 30-day location signal set to expire.
Angus Houston, Australia's former military chief and now coordinator of the eight-nation search, said "we're now getting pretty close to the time when it might expire."
The plane went missing en route from Kuala Lumpur to Beijing with 239 people on board, confounding aviation experts and sparking criticism of Malaysian authorities who have been unable to explain how the jumbo jet vanished.
Undersea search commences
Anwar said he was "baffled" by the Malaysian military's failure despite detecting the plane crossing back over the country's airspace following its mysterious detour.
"Unfortunately the manner in which this was handled after the first few days was clearly suspect," Anwar said in an interview with Britain's Daily Telegraph.
"One fact remains. Clearly information critical to our understanding is deemed missing. I believe the government knows more than us," he added, without elaborating.
Malaysian authorities believe satellite data indicates MH370 crashed in the Indian Ocean, far off western Australia.
Ocean Shield, which also bore an underwater drone vehicle capable of mapping the seafloor, joined in a search with the British navy's hydrographic ship HMS Echo, which on Thursday began scanning for black box transmissions.
But despite days of exhaustively scouring the sea's surface with planes and ships, no debris has been found to prove MH370 went down in the area, let alone pinpoint a crash site.
Australian Commodore Peter Leavy admitted the undersea search was a shot in the dark for hopes that a ping can be picked up, adding that the two ships would need to move at excruciatingly slow speeds in the deep waters to improve the chances.
"No hard evidence has been found to date so we have made the decision to search a sub-surface area on which the analysis has predicted MH370 is likely to have flown," he said.