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Jet Search Team Says Signals Are ‘Consistent’ With Black Boxes
Hunt for Malaysian Jet Tests Technical Limits
(about 9 hours later)
KUALA LUMPUR, Malaysia — Even as they celebrated the discovery of underwater signals that may have come from Malaysia Airlines Flight 370, the authorities involved in the search cautioned on Monday that they were still far from confirming the location of the airliner and solving the mystery of its disappearance.
HONG KONG — The metronome-like pings that may signal the flight data recorders from Malaysia Airlines Flight 370 emanate from the stygian depths in the eastern Indian Ocean, 2.8 miles below the waves, where the water pressure is more than three tons per square inch. The bottom is a quarter-mile deeper than even the sandy plain near the Mid-Atlantic Ridge where the black boxes of Air France Flight 447 were found off the coast of Brazil nearly three years ago.
The Australian naval vessel Ocean Shield, equipped with technology on loan from the United States Navy, picked up a series of electronic pings on Sunday that had the characteristics of transmissions from a plane’s data and cockpit voice recorders, commonly known as black boxes.
These are just some of the formidable obstacles that remain in finding and recovering whatever is left of the Boeing 777 that vanished a month ago with its 239 passengers and crew.
But on Monday afternoon, officials said the ship had been unsuccessfully trying to locate the signals again as it slowly swept a remote section of the Indian Ocean, hundreds of miles northwest of Perth, Australia.
While an Australian official described the pings as the “most promising lead” in the search for the plane so far, experts described the task ahead as monumental.
Personnel from the United States Navy, who are operating the underwater detection equipment on Ocean Shield, are hoping to achieve more “signal detections” to be able to pinpoint the source of the pings, said Cmdr. William J. Marks, a spokesman for the Navy’s Seventh Fleet, which is overseeing American naval participation in the search. But the process is slow and deliberate.
There is no confirmation that the signals are coming from a submerged black box, and little time left before the boxes no longer have battery power to emit the pings. Even if the signals lead to the boxes, the search for wreckage at the bottom of the ocean could take weeks or months, and only then could the mystery of what happened to the plane begin to be unraveled.
At the same time, the batteries in Flight 370’s black boxes were expected to expire this week. The closer to expiration, the weaker the pings.
An American remote-controlled submersible sonar device will be lowered as soon as Tuesday to scout for wreckage if a towed “pinger” locator can obtain a reliable position for their source. If sonar identifies possible wreckage, the submersible will be pulled up, refitted with a camera for close-up images and sent back down, Australian officials said.
If the searchers aboard Ocean Shield can define a more precise area where the black boxes might be located, they will then deploy a remote-controlled unmanned submarine to map the ocean floor and look for wreckage and the black boxes. The water at the vessel’s location is about 2.8 miles deep — about the farthest the submarine, a Bluefin-21, can dive.
But the estimated depth, nearly 15,000 feet, is already at the very limit of the submersible’s certified range. “We’re right on the edge of capability, and we might be limited by the capability if, for example, the aircraft ended up in deeper water,” said Angus Houston, the retired air chief marshal who used to run Australia’s armed forces and is now overseeing the search.
But Commander Marks said that without a fairly precise idea of the black boxes’ location, “using just the Bluefin with an estimate is going to be an extremely long process.”
The towed pinger locator, essentially a powerful set of microphones towed through the depths at the end of several miles of cable, is operating in the undersea equivalent of an echo canyon. Differences in water pressure, salinity and temperature can send noises ricocheting in unpredictable ways, unlike the fairly straight lines along which sounds are usually transmitted in the air.
If the plane’s black boxes are found, the effort will become a recovery operation. At such depths, that could take “a long, long time,” measurable in months, said Angus Houston, the retired Australian Air Force chief who is the lead coordinator of the search.
“That has the effect of attenuating, bending — sometimes through 90 degrees — sound waves,” said Commodore Peter Leavy of the Royal Australian Navy, who is helping to lead the search.
“This is not the end of the search,” Mr. Houston said during a news conference in Perth on Monday. “We’ve still got a lot of difficult, painstaking work to do.”
Despite that complexity, search officials were more optimistic on Monday than they had been in weeks. The operators of the towed locator, aboard the Ocean Shield, an Australian vessel, heard a steady pinging for 2 hours and 20 minutes during a pass on Sunday afternoon.
“In deep oceanic water,” he said, “nothing happens fast.”
After turning around, the team heard pings again for an additional 13 minutes, and from two different locations, which would be consistent with the two black boxes that the missing plane was carrying. Turning around the pinger locator is a laborious process requiring several hours because the locator must be reeled in before the ship can perform a U-turn and then lower the device once more into the depths.
Officials continued to caution against drawing any conclusions about the source of the signals, warning that false alerts could be set off by a range of influences, including sea life — such as whales — or by noise from ships.
The refraction of undersea noises can complicate what is an otherwise straightforward process. The towed pinger locator can identify the compass bearing from which a sound is coming. As the locator is towed, the direction to an acoustic source gradually changes.
Mr. Houston said he doubted that the signals detected by Ocean Shield were caused by natural sources. But, he added, “strange things do happen in the ocean, and I would want more confirmation before we say, ‘This is it.’ ”
The device’s operators then calculate a series of straight lines on a map, using the location of the locator when it heard each sound and the angle at which the sound arrived. “Where they cross and make an X, if you get enough of them, then you should be pretty certain of your fix,” said Cmdr. William J. Marks, a spokesman for the United States Navy’s Seventh Fleet.
Despite all the uncertainties, the authorities heralded the series of underwater signals as a possible breakthrough in the search for the plane, a Boeing 777-200 with 239 people aboard.
But the team on the Ocean Shield was unable to relocate the pings during an initial pass through the same area on Monday. Searchers were hoping to re-establish contact because the sonar submersible, known as a Bluefin-21, has an even shorter horizontal range than the towed pinger locator.
The signals were detected Sunday about 1,050 miles northwest of Perth, officials said.
“Let’s say we don’t reacquire the signal, and we don’t get a good fix on where the black box is,” Commander Marks said. “It will be extraordinarily difficult to use the Bluefin in a location where we’re really not certain.”
“Clearly, this is a most promising lead,” Mr. Houston said. He called the signals “probably the best information that we have had” on the search, which, over the past three weeks, has migrated across a vast area of the Indian Ocean hundreds of miles off the west coast of Australia.
Time is not on the searchers’ side. The batteries in the black boxes were designed to last 30 days, and 31 days have elapsed since the plane vanished. The pings are not likely to stop all at once, experts say, but fade to a whisper and then nothing.
“I’m much more optimistic than I was a week ago,” Mr. Houston said.
Yet there were signs that the black box signals were still going strong at least on Sunday. The towed pinger locator initially detected a signal when it was only 1,000 feet deep, the Seventh Fleet said in a statement, adding that it was unusual for the signal from a black box on a deep ocean floor to reach such shallow waters.
Officials said that determining the nature and source of the signals might take several days, and that there was still no proof of the plane’s whereabouts.
One of the biggest surprises in the announcement of the pings Monday afternoon was that the towed locator seemed to have found anything at all. When the initial acoustic contacts were made on Sunday, it was only the third day that the device had been used in the search of the Indian Ocean.
“I would now like to find some wreckage because that will help solve the mystery,” Mr. Houston said. “Fundamentally, without wreckage, we can’t say it is definitely here.”
Australia’s Joint Agency Coordination Center, which is organizing the search, said on Monday morning that the effort covered an area of 234,000 square kilometers, or about 90,000 square miles.
Search forces began deploying the underwater listening technology only last Friday, in a last-ditch effort to hear the black boxes’ signals before they faded.
By contrast, the towed pinger locator moves at no more than 3 knots, or 3.5 miles per hour, and covers a two-mile-wide swath as it does so, for just seven square miles in an hour.
The signals picked up by Ocean Shield occurred over the course of about five and a half hours late Sunday in the northern part of the current search zone, northwest of Australia, officials said.
The shallowness of the initial contact by the pinger locator raised at least the possibility that the Ocean Shield’s captain had more information about the possible location of the aircraft than has been publicly disclosed.
The sensors first detected the signal — a series of consecutive pings at one-second intervals — in the late afternoon and held it for more than two hours, officials said. The ship lost contact, turned around, and picked up the signal again for about 13 minutes, officials said. On the return leg, sensors detected pings coming from two different locations, suggesting transmissions from both black boxes.
Britain has said that it has dispatched a nuclear submarine to help in the search. The United States has a policy of not disclosing the locations of its submarines. The United States Navy does not disclose the maximum operating depth for its attack submarines and ballistic missile submarines, as opposed to deep-sea research submarines, but says on its website that they can dive to at least 800 feet.
The announcement seemed to offer the best indication so far that after more than four weeks of fruitless searching across vast areas of sea and land in the Eastern Hemisphere, officials might finally be zeroing in on concrete evidence of the plane and its fate.
Commander Marks declined to comment on whether the United States had provided any additional data to Australia beyond what has been publicly disclosed.
The Malaysia Airlines plane disappeared on March 8 after it veered off its scheduled route to Beijing from Kuala Lumpur, and vanished from civilian and military radar. Based on analyses of satellite data, officials concluded that the flight ended somewhere in the southern Indian Ocean.
China announced on Saturday that one of its vessels, the Haixun 01, had detected pings. But China’s method for searching, in which sailors hold a marine listening device over the side of the boat, drew skepticism from oceanographers and other search experts, especially as the Chinese vessel was 375 miles away from where the Ocean Shield twice identified frequent pings.
Further data analysis has refined the search, and in the past week and a half ships and aircraft from several nations have been combing a broad swath of the Indian Ocean off the coast of Western Australia.
Mr. Houston, the Australian leading the search, said that the Chinese site would also be investigated with care.
Despite these efforts, no confirmed debris from the jet has been found.
Commander Marks refused to answer questions about whether the United States had provided other, unpublicized information and guidance on the possible location of where the plane went down.
The Ocean Shield is outfitted with a so-called towed pinger locator, a batwing-shaped device that is towed behind the vessel, deep in the water, and can pick up signals from the black boxes’ beacons. The locator is towed at no more than about 3.5 miles per hour and has a range of about a mile. In addition, simply turning the ship around and resetting the locator can take several hours each time.
“If we did hear the pings from the black box, I think we’re very lucky,” Commander Marks said. “It of course could go longer than 30 days, but I think we take every day and are thankful for that.”
Over the weekend, searchers’ hopes had shifted to a spot about 375 miles southwest of Ocean Shield, and about 1,000 miles northwest of Perth, where a Chinese ship in the flotilla had reported capturing two signals thought to be from the flight’s black boxes.
A ship from the British Navy also equipped with underwater listening technology was diverted from another area in the Indian Ocean to investigate the findings of the Chinese vessel, which reported that its underwater devices had picked up signals on Friday and Saturday that were consistent with the pings emitted by a plane’s black boxes. In all, nine military planes, three civilian planes and 14 ships were participating in the search effort on Monday.
Mr. Houston said that the signals picked up by the Chinese vessel, Haixun 01, would still be pursued.
“We have to prosecute both contacts,” he said. “We don’t know at the moment, we don’t have any confirmation, that one or the other is significant enough for us to say, ‘Yes, this is where the aircraft is.’ We have to have further confirmation, and I would put it to you that we cannot confirm until we have found some wreckage.”
Mr. Houston said it was “unlikely” that the signals heard by Haixun 01 came from the same source as the signals heard by the Australian vessel. “But in deep water, funny things happen with acoustic signals,” he said.
In Malaysia, Hishammuddin Hussein, the country’s defense minister and acting transport minister, said Monday that the announcement in Perth had made him “cautiously hopeful.”
“We have been through a real roller coaster ride based on leads that we have received,” he said. “But as usual, some leads are much more positive than others.” He added, “I would like everybody to continue to pray.”
