Australian and U.S. Navy officials said they have detected more acoustic signals that may belong to a black box from the missing Malaysia Airlines jet. However, they are stressing that the airliner's location cannot be confirmed until wreckage from flight MH370 is spotted on the surface or under the Indian Ocean.
Authorities Monday said they are very encouraged, but nonetheless remain cautious, amid the clearest indications yet of where the wreckage of Malaysia Airlines flight MH370 could be.
The best clues during the month-long search have been picked up by U.S. Navy black box detection equipment being towed by an Australian naval ship in deep waters more than 1,500 kilometers northwest of Perth, Australia.
Retired air chief Angus Houston, the leader of the Australian team coordinating the international search effort, said the first detection of acoustic signals on a frequency of 37.5 kilohertz was held for 2 hours 20 minutes. The second detection, on a return leg, was heard for 13 minutes.
"Significantly, this would be consistent with transmissions from both the flight data recorder and the cockpit voice recorder. Clearly this is a most promising lead," said Houston.
A British naval vessel, the HMS Echo, is heading to an area where a Chinese patrol ship, the Haixun-01, using a hydrophone dangled over the side of the boat, detected acoustic pings Friday and Saturday about two kilometers apart.
Houston said the vessels are in a race against time to receive further underwater signals.
"The life of the batteries must be getting somewhere close to the end of life. It's what, 31 days, so we're already one day past the advertised shelf life. We hope that it keeps going for a little bit longer," said Houston.
Royal Australian Navy commodore Peter Leavy said searchers hope to use equipment to begin exploring the ocean floor if they detect more of the suspected black box signals.
"If they gain another acoustic event on that towed pinger locator that would be the trigger, at the moment, to launch the autonomous underwater vehicle with the underwater sonar and, potentially, camera for mapping and visually looking at the ocean floor," said Leavey.
In the area where the acoustic pulses have been detected, the ocean floor is about 4,500 meters below the surface. That is the limit of the operating depth for the autonomous underwater vehicle.
Officials caution it could be weeks, or possibly months, before anything is found at that depth over what is still a wide search area.
Malaysia Airlines Flight 370 disappeared on March 8 during a flight from Kuala Lumpur to Beijing. The aircraft was carrying 239 people. Most of the passengers were Chinese.