(KUALA LUMPUR, Malaysia) -- Malaysian authorities believe the last words spoken to air traffic control before Malaysia Airlines Flight MH370 disappeared came from the co-pilot.
"The initial investigation indicates it was the co-pilot who basically spoke the last time it was recorded on tape," Malaysia's acting transport minister, Seri Hishammuddin Hussein, told reporters Monday.
The final radio transmission before the Boeing 777 vanished on March 8 was, "All right, good night." Hussein said the voice is now being analyzed for any signs of stress.
"If he made transmissions before, can you tell any differences in his voice based on frequency, stresses and things like that," ABC News consultant Tom Haueter, a former National Transportation Safety Board investigator, said, explaining what officials will be looking out for.
Meanwhile, the search for the missing airliner with 239 people on board is showing a new emphasis on areas near Australia with more search planes scouring the region.
Australia is sending two P-3 Orion and one C-130 aircraft to aid in the search effort and a U.S. P-8 aircraft is traveling to Perth, Australia, to help in the hunt.
Australia is coordinating the search in the southern Indian Ocean. The decision for Australia to take the lead was suggested by Malaysia Prime Minister Najib Razak.
“In assuming overall responsibility for coordinating the search effort in the southern Indian Ocean, Australia is preparing to work with assets from a number of other countries, including surveillance aircraft from New Zealand and the United States,” Australia Prime Minister Tony Abbott said in a statement.
Investigators believe that two of the plane's communications system were manually shut down, but the plane continued to ping satellites for up to seven hours. Those pings identified the plane’s possible last location along corridors to the north or south.
The southern corridor would have taken the plane over open water to a point off Australia's western coast where it would have run out of fuel and crashed into the Indian Ocean.
Other countries are searching the northern route, but that area includes nations whose radar would have likely picked up a sign of the plane, and there have been no reports of the plane being spotted on radar.
The search operation for the plane now involves 26 countries, covering land in 11 countries as well as deep and remote oceans.
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