Investigators probe plane sign-off
Investigators are conducting a forensic examination of the final recorded conversation between ground control and the cockpit of Malaysia Airlines Flight 370 before it went missing three weeks ago, the Malaysian government said.
It comes after the Malaysian government changed its account of the final voice transmission from the missing jetliner.
The examination could shed light on who was in control of the cockpit and will also seek to determine if there was any stress or tension in the voice of whoever was communicating with ground control - crucial factors in an air disaster investigation.
Responding to repeated media requests, the Malaysian government released a transcript of the conversation, which showed normal exchanges from the cockpit as it requested clearance for take-off, reported it had reached cruising altitude and left Malaysian air space.
"Good night Malaysian three-seven-zero," were the final words received by ground controllers at Kuala Lumpur's international airport. The government yesterday changed its account of the final voice transmission which it had earlier transcribed as "All right, good night".
The three-week hunt for Flight 370 has turned up no sign of the jetliner, which vanished on March 8 with 239 people on board bound for Beijing from Kuala Lumpur.
The search zone has repeatedly shifted as experts analysed the plane's limited radar and satellite data, moving from the seas off Vietnam to waters west of Malaysia and Indonesia, and then to several areas west of Australia. The current search zone is a remote 98,000 square mile area off Perth.
The new development came as Australia, which is co-ordinating the search for the Boeing 777, cautioned that it "could drag on for a long time".
Australia has deployed an airborne traffic controller over the Indian Ocean to prevent a mid-air collision among the many aircraft searching for the missing plane.
An Australian Air Force E-7A Wedgetail equipped with advanced radar "is on its first operational" task in the search area in the middle of the Indian Ocean, the Australian Maritime Safety Authority said in a tweet.
Earlier, Angus Houston, who heads the joint agency co-ordinating the multinational search effort, said the modified Boeing 737 will monitor the increasingly crowded skies over the remote search zone.
Eleven planes and nine ships are focusing on less than half of the search zone, 46,000 square miles of ocean west of Perth, with poor weather and low visibility forecast, according to the new Joint Agency Co-ordination Centre. A map from the centre showed that the search area was about 1,200 miles west of Perth.
Some of the aircraft have been dropping as low as 200ft above the water - and occasionally dipping even lower for brief periods - raising concerns of collisions with ships crisscrossing the zone.
The arrival of the E-7A "will assist us with deconflicting the air space in the search area," Mr Houston told reporters in Perth. The plane can maintain surveillance over a surface area of 156,000 square miles at any given time, according to the air force's website.
Mr Houston, a former Australian defence chief, called the search effort the most challenging one he has seen.
"In this particular case, the last known position was a long, long way from where the aircraft appears to have gone," he said. "It's very complex, it's very demanding.
"What we really need now is to find debris, wreckage from the aircraft. This could drag on for a long time."
Australian prime minister Tony Abbott has said that although the search for the aircraft has been slow, difficult and frustrating, it will continue indefinitely.
He said the intensity and magnitude of operations "is increasing, not decreasing", and added: "If this mystery is solvable, we will solve it."