An Australian aircraft on Thursday may have detected the latest in a series of deep-sea acoustic signals, authorities involved in the hunt for a missing Malaysian airliner said, raising confidence that search teams are closing in on wreckage that presumably lies at the bottom of the Indian Ocean.
Officials say the detections over the past six days could be black-box signals from Malaysia Airlines Flight 370. The first four transmissions were picked up by an Australian navy vessel, the Ocean Shield. But the latest “possible signal” was detected by an Australian surveillance plane operating in the same area, the Australian agency coordinating the multination search said in a statement.
The plane, an Australian air force P-3 Orion, has been dropping sonar buoys — listening devices — in the vicinity of where the earlier pings were heard.
“The acoustic data will require further analysis overnight but shows potential of being from a man-made source,” retired Air Chief Marshal Angus Houston, who is in charge of the search, said in a statement.
The signals, though not conclusively linked to the plane, have reinvigorated a search that had languished for weeks amid dead ends and false leads. Houston said Wednesday that he believed that crews might identify evidence of the plane’s remains within days.
The search is centered on an area about 1,415 miles northwest of Perth, a city on the western coast of Australia. The planned search area Thursday — about 22,300 square miles — is the smallest since the plane vanished March 8.
The disappearance of Flight 370, which was carrying 227 passengers and 12 crew members from Kuala Lumpur, Malaysia, to Beijing, has turned into one of the most confounding aviation mysteries on record. The Boeing 777 is presumed to have crashed in the southern Indian Ocean, having traveled in its final hours in a direction opposite to its scheduled flight path. Malaysian officials say the plane was deliberately steered off course by somebody on board, though they have not completely discounted the possibility of some kind of mechanical failure.
“At the end of the day, if we do not stray from the course, we will find out” some answers about what happened to the plane, Malaysian Defense Minister Hishammuddin Hussein said Thursday in an interview with the BBC. “I know we will find the plane. It’s just a matter of when.”
Australian officials had few details about the latest detection and did not specify the location of the transmission.
The surveillance plane was able to listen for the deep-sea sounds because of a move Wednesday to drop the sonar buoys. The buoys stay on the surface but deploy hydrophones to a depth of 1,000 feet. The buoys are equipped with radios that transmit any data back to the aircraft.
The search for Flight 370’s flight data recorder and cockpit voice recorder is a daunting task, and it will ultimately require not just listening devices but also underwater drones and robotic, clawlike devices that could retrieve debris. For now, though, search teams are trying only to pick up more transmissions, which would allow for a better estimate about where to begin the labor-intensive underwater operation.
The black-box emergency beacons could run out of battery power within hours or days, Australian officials say. Already, they may be operating beyond their expected 30-day power supply. Search officials have not concluded that the signals are coming from a black box, but they say the frequencies are consistent with what would be expected of tracking pings from a black box.
An underwater drone, known as the Bluefin-21, will begin deep-dive sorties only after more signals are detected or officials determine that the black-box batteries have probably died. The Bluefin-21 would be operating in about three-mile depths, near its technical limit.
The detection of additional pings could help narrow the underwater search area, which is about 500 square miles. The Bluefin-21, which moves about four mph, would need weeks to cover that zone. It would first travel to the depths and probably make overlapping, back-and-forth patterns over the search area.
“The system can be programmed to follow a number of possible routes,” Christopher Johnson, a spokesman for the U.S. Naval Sea Systems Command, said in an e-mail, “but the most likely would follow a pattern that would resemble how someone might mow their lawn — back and forth over the area until the entire programmed sector is covered.”
Johnson added, “We believe the equipment will be able to operate at the depths we would likely encounter.”