Tick, tock: What happens after Malaysia Airlines Flight 370's pingers die?

(CNN) -- A Chinese ship detects a pulse signal deep in the Indian Ocean at the same frequency used by so-called black boxes like the one aboard missing Malaysia Airlines flight 370.

After almost a month of fruitless searching, hopes mount for final answers about what happened to the plane carrying 239 people that disappeared almost a month ago.

However, experts disagree if Saturday's news is a breakthrough or another dead end, raising new questions about what the pulse signal means and what happens now.

Is this it?


The signal reported -- 37.5 kHz -- "is the standard beacon frequency" for the plane's cockpit voice recorder and the flight data recorder, said Anish Patel, president of pinger manufacturer Dukane Seacom.

That frequency was chosen for use in the recorders "to give that standout quality that does not get interfered with by the background noise that readily occurs in the ocean."

However, Patel wondered why only one signal had been detected because the plane had two recorders equipped with pingers, which also are called beacons. They were located next to each other near the tail of the plane, and presumably would both still be emitting signals.

China's Xinhua news agency reported the detector deployed by the Haixun (pronounced "high shuen") 01 patrol ship picked up the signal around 25 degrees south latitude and 101 degrees east longitude, adding "it is yet to be established whether it is related to the missing jet."

That location is outside the previously announced search areas for the missing plane off the western coast of Australia in the Indian Ocean. A Chinese search plane also reported seeing white objects on the ocean surface, according to Xinhua.

Later Saturday, the head of the Joint Agency Coordination Centre in Australia that is overseeing the search said there was "no confirmation at this stage that the signals and the objects are related to the missing aircraft." The statement said the floating objects were 90 kilometers, or about 55 miles, from where the pulse signal was detected.

Why wouldn't this be it?

Many things in the ocean can have a frequency range similar to the pulse signal detected by the Haixun 01 patrol ship, according to oceanographers.

Greg Stone, chief scientist at Conservation International, said sources for the pulse signal could be the Chinese vessel itself, marine life that can make sounds in or near that range, or equipment left by scientists to help them find gear left in the ocean.

"There's a lot of possibilities for sonar sources ... out there," Stone said.

Others questioned China's role in the new information, which came from its state-run news agency.

"I am very skeptical, along with everyone else," said Peter Goelz, former managing director of the National Transportation Safety Board. "The Chinese have not been good team players in this. Many have thought that they have been manipulating the situation."

What now?

Searchers need more equipment in the area where the pulse signal was detected to determine if it comes from airplane wreckage.

It is a race against time, because the batteries for the acoustic pingers on Flight 370 could run out soon. The y are expected to last at least a month once a plane goes down, but would then begin to lose strength. According to Malaysian officials, the batteries on the missing plane were due to be replaced in June under a regular maintenance schedule.

"I'd like to see some additional assets on site quickly -- maybe some sonobuoys," Patel said, referring to 5-inch-long (13-centimeter) sonar systems that are dropped from aircraft or ships.

Confirmation that the signal comes from the Malaysia Airlines Boeing 777 would mean "the possibility of recovering the plane -- or at least the black boxes -- goes from being one in a million to almost certain," said Simon Boxall, a lecturer in ocean and earth science at the University of Southampton.

Up to 10 military planes and three civilian aircraft -- in addition to 11 ships -- searched Saturday for any sign of Flight 370, according to Australian officials. The British submarine HMS Tireless was in the search area, Malaysia's acting transport minister said.

Retired Air Chief Marshal Angus Houston, the chief coordinator of the JACC, said officials were considering deploying search assets to the specific area where the Chinese ship detected the pulse signal.

CNN's Tom Watkins, Laura Smith-Spark, Will Ripley, Ingrid Formanek, Kevin Wang, Ben Brumfield, Pam Brown, Elizabeth Joseph, Aaron Cooper, Mike M. Ahlers and Rene Marsh contributed to this report.

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