The underwater vessel searching for traces of the missing Malaysian jet resurfaced Wednesday to fix a technical issue, but then redeployed again.
While on deck, its data were downloaded, the Australian Joint Agency Coordination Centre said.
"Bluefin-21 ... is currently continuing its underwater search," it said in a statement. "Initial analysis of the data downloaded this morning indicates no significant detections."
This is the second setback for the underwater vehicle deployed to scan the ocean floor for debris linked to Malaysia Airlines Flight 370.
In its first dive Monday, crews dipped it into the Indian Ocean on what was expected to be a 20-hour deployment. It returned less than eight hours later after it exceeded its maximum dive depth.
"What Bluefin did was it detected that it was moving was near its maximum depth, sending signals back to its operators, said Mike Dean, the U.S. Navy deputy director for salvage and diving.
" After the two signals which was deeper than what we anticipated, the operators decided to bring it back and reassess the boundaries in which they were operating it," he said.
It found no debris during its shortened scanning session.
Searchers lowered it toward the ocean floor for a second dive Tuesday, and it resurfaced short of its 24-hour mission because of technical issues. It then went down again.
Bluefin-21 takes two hours to get near the ocean floor and another two hours to return to the surface. It aims to map the ocean floor for 16 hours to retrieve data, which then take four hours to analyze.
The vessel searches maximum depths of 4,500-meter (14,764-foot), and before the technical interruption, was scheduled to complete its second dive about 10 a.m. ET, a source said. It's unclear when it will finish its current mission following the resurfacing.
"We have known a long time that especially the recent search area, the new search area they are looking at now there's a lot of debris there because it is close to what we call the garbage patch and that's where all of the garbage accumulates," said Erik Van Sebille, physical oceanographer at University of New South Wales.
In the search for Malaysia Airlines Flight 370, a plane has detected a possible signal from the locator beacons on the so-called black boxes from the missing aircraft, the Australian agency coordinating the search announced Thursday.
"The acoustic data will require further analysis overnight but shows potential of being from a man-made source," said retired Air Chief Marshal Angus Houston, the agency's chief coordinator.
The possible signal, which was picked up through sonar buoys equipped to receive such electronic data, was detected near the Australian ship Ocean Shield, said the Joint Agency Coordination Centre.
Crews have been narrowing the search area in the Indian Ocean.
Up to 10 military aircraft, four civil aircraft and 13 ships were to assist in Thursday's search for the Boeing 777-200ER, which was carrying 239 people when it vanished March 8 on a fight from Kuala Lumpur, Malaysia, to Beijing.
Three of the vessels - the Ocean Shield to the north, and the British HMS Echo and Chinese Haixun 01 to the south - were focusing underwater.
Aircraft and ships spotted a number of objects during Wednesday's search, but could recover only a small number, none of which appeared linked to MH370, the JACC said.
Thursday's search area is about 22,400 square miles (58,000 square kilometers), centered some 1,417 miles (2,280 kilometers) northwest of Perth. That's roughly the size of West Virginia.
But the latest search area is about three quarters of the size of the area that teams combed the day before and far smaller than what it was a few weeks ago.
We'll have the latest developments on this story on @ThisHour at 11am ET/ 8am PT.
Authorities have identified the man who opened fire at Fort Hood in Texas on Wednesday, killing three people before committing suicide, as Specialist Ivan Lopez.
Sixteen more people were injured Wednesday when he opened fire at Fort Hood, the sprawling Army post in Texas still on edge after a mass shooting there left 13 dead in 2009, officials said.
The gunman also died. He was engaged by military police before he fatally shot himself in the head, said the Army post's commander, Lt. Gen. Mark A. Milley.
Dr. Matthew Davis, Trauma Director at Scott and White Memorial Hospital, gave an update on the conditions of the patients at 11:37am ET this morning:
"We do have nine patients here at Scott and White, three of them remain in critial condition, and the remainder are in good condition. There is a possibility that some of them may actually be discharged from the hospital today..."
WATCH VIDEO ABOVE.
Find out what causes people to snap after being in war zones.
For more as this story develops, head to CNN.com.
Shootings at military installations are not uncommon. Last year, a shooting at the Washington Navy Yard left 12 people dead, and two people were killed at the Quantico Marine corps base in Virginia.
In 2009, there was the Fort Hood shooting that killed 13, and in the 1990s there were shootings at both Fort Bragg in North Carolina, and Fairchild Air Force base in Spokane, Washington.
Terry Lyles, psychologist and combat stress coach, spoke to John Berman and Michaela Pereira on @THIS HOUR to give some insight on what causes people to snap, and what kind of treatment people returning from war zones need.
What causes people to snap?
Lyles: There’s such a huge challenge in coming back from war and having to re-assimilate back into society, it’s not as easy as it sounds, obviously. But I think the biggest thing is that these individuals try to normalize after coming back and living in that kind of chaos… and it’s not easy to transition quickly and get back to society as we know it here in a safe community.
For the men and women returning from war zones, like Iraq and Afghanistan, what kind of treatment do they need?
Lyles: I work directly with the VA, I’m actually on a plane shortly heading that direction, and let me tell you, I think the VA is doing a great job with what they have to work with and they realize there’s a gap between coming back and treating for potential PTSD, and then actually putting a protocol together to help them. And that delayed process is part of the challenge. I know people that go months at a time without getting… the proper care that they need just because of the sheer number of the drawl down of the troops coming back. So there’s several potential challenges here, but the community at large, I think all of us, have a responsibility to support our soldiers and watch for signs, and try to help them in any way possible to re-assimilate back into society like most of us never have to do because we don’t go to that theater of war.
A doctor treating the injured from the Fort Hood shooting gives an update on the conditions of the patients. WATCH.
For more as this story develops, head to CNN.com.