A Chinese ship involved in the hunt for the missing Malaysian jetliner reported hearing a "pulse signal" Saturday in Indian Ocean waters with the same frequency emitted by the plane's data recorders.
China's official Xinhua News Agency said a black box detector deployed by the ship, Haixun 01, picked up a signal at 37.5 kilohertz (cycles per second). However, Xinhua said it had not yet been determined whether the signal was related to the missing plane, citing the China Maritime Search and Rescue Center.
Malaysia's civil aviation chief, Azharuddin Abdul Rahman, confirmed that the frequency emitted by Flight 370's black boxes was 37.5 kilohertz.
Retired Air Chief Marshal Angus Houston, Chief Coordinator of the Joint Agency Coordination Center -- the Australian government agency coordinating the search -- said Saturday the Haixun's report of electronic pulse signals could not be verified at this time. U.S. officials from the NTSB and FAA were not able to confirm the report, either.
Houston also said the report of a number of white objects on the water's surface about 90 kilometers from the signal detection area could not be confirmed to be related to the missing plane.
The deployment of Royal Australian Air Force assets to the area where the Chinese ship detected the sounds is being considered, Houston said.
CBS News Transportation Safety Analyst Mark Rosenker, a former chairman of the NTSB, wondered why there was no report of debris from the Chinese ship that detected the signal: "When you think about what in fact they are saying, which means they believe they have the debris site where the aircraft is laying, it defies logic that we would not be seeing something on the surface as well," Rosenker said.
But Sky News senior correspondent Ian Woods told CBS News Radio, "The reason it is being given some credibility is because even though there are many items that could be mistaken for wreckage floating round in the ocean, there is only one thing that pulses at 37.5 kilohertz, and that is a 'black box' recorder."
On Thursday, the British navy's HMS Echo reported one alert as it searched for sonic transmissions from the missing plane's flight data recorder, but it was quickly discounted as a false alarm, the Joint Agency Coordination Center overseeing the search said. False alerts can come from animals such as whales, or interference from shipping noise.
With the batteries in the black boxes' locator beacons due to run out any day, crews are in a desperate race against the clock.
On Friday for the first time, crews launched an underwater search trying to pick up a signal from the black box flight recorders on the Beijing-bound plane before they are expected to fall silent. The batteries last only about 30 days, which would be Monday.
The search for the Boeing 777 -- plagued by confusion, and agonizing to relatives of the 239 passengers -- has frustrated investigators and left many wondering how long it can go on.
Two naval ships from Australia and the United Kingdom began probing the ocean along a 150-mile route on Friday that investigators hope is close to where Malaysia Airlines Flight 370 went down. The Australian ship, Ocean Shield, is towing a U.S. Navy device that can detect signals or pings from the flight data and cockpit voice recorders, commonly known as the black boxes.
The U.S. Navy's towed pinger locator can pick up signals to a depth of 20,000 feet, and so should be able to hear the plane's data recorders even if they are at the deepest part of the search zone, about 19,000 feet.
But no wreckage from the plane has been found, so officials cannot even be sure they are looking in the right location. The 84,000-square-mile search area, about 1,100 miles northwest of Perth, was already shifted almost 700 miles to the north after investigators decided that the plane was traveling faster than originally thought.
Plus, the pinger locator -- consisting of a 30-inch cylindrical microphone attached to about 20,000 feet of cable -- must be dragged slowly through the water at just 1 to 5 knots (or 1 to 6 mph) in a grid pattern.
Meanwhile, up to the 11 military planes, four civilian jets and 11 ships were to assist in Saturday's search, led by the Australia Maritime Safety Authority. Australian officials The Australian Transport Safety continue to refine the area where the plane entered the water based analysis of satellite communication and the aircraft's performance.
The Malaysia Airlines jet left Kuala Lumpur on Saturday, March 8, at 12:41 a.m. headed for Beijing. But investigators believe someone re-programmed the plane's flight management system, and two minutes after the last conversation between air traffic controllers in Malaysia and the cockpit, the plane's transponder was turned off. The plane went dark on civilian radar, and then made a left turn back toward Malaysia.
Sources have said it followed an established aviation corridor over several navigational "waypoints."
The Malaysian military tracked an unidentified object now believed to have been Flight 370 on its radar traveling west towards the Strait of Malacca. At 2:15 a.m., it disappeared from the military radar, about 200 miles northwest of Penang.
Investigators say the plane's antenna signaled to a satellite multiple times over the next several hours, with the last signal recorded at 8:11 a.m., about the time the plane would have run out of fuel.
Experts says the search in the southern Indian Ocean might have been easier had the plane been outfitted with so-called "deployable black box" technology, essentially flight recorders that eject and float when a plane crashes.
The U.S. Transportation Safety Administration tested the technology, employed on U.S. Navy jets such as the F/A-18 for more than two decades, and found that it would enhance safety on commercial aircraft. But three years after the study, no U.S. commercial airline has installed the technology. The price tag per plane is about $60,000.
As the search for the missing Malaysian jet entered its fifth week, Australian Air Chief Marshal Angus Houston, head of the joint agency coordinating the operation, has acknowledged the search area was essentially a best guess.
"They might be lucky and they might start smack bang right over the top of it," said Geoff Dell, discipline leader of accident investigation at Central Queensland University in Australia. "But my guess is that's not going to be the case and they're in for a lengthy search."