Objects spotted in Indian Ocean may be debris from Malaysia Airlines Flight 370

Kuala Lumpur, Malaysia (CNN) -- Two objects spotted in the southern Indian Ocean may be debris from the missing Malaysia Airlines Flight 370, Australian authorities said Thursday.

The objects are indistinct but of "reasonable size" -- the largest about 24 meters long (79 feet), said John Young, general manager of emergency response for the Australian Maritime Safety Authority. They were "probably awash with water and bobbing up and down," he said.

"If that piece of the plane is that big, maybe it's the tail section" said David Gallo, who co-led the search for Air France Flight 447, which crashed in the Atlantic Ocean in 2009. But he warned that the size gave him a degree of concern.

"It's a big piece of aircraft to have survived something like this," he said.

The tail height of a Boeing 777, the model of the missing Malaysian plane, is 60 feet.

The announcement raises hopes of finding parts of the plane amid a huge search that is now in its 13th day. Previous reports of debris found in the sea haven't turned out to be related to the passenger jet, which vanished over Southeast Asia on March 8.

Australian Prime Minister Tony Abbott first announced the discovery to the House of Representatives in Canberra on Thursday. Australian search teams have been at the forefront of the hunt for the missing plane in the remote southern Indian Ocean.

"There have been so many false leads and so many starts and changes and then backtracking in the investigation," said Mary Schiavo, a CNN aviation analyst and former inspector general for the U.S. Department of Transportation. "He wouldn't have come forward and said if they weren't fairly certain."

But officials cautioned that there were no guarantees that the objects now being investigated would prove to be from the missing plane.

At the Lido Hotel in Beijing where family members of some of the passengers on the missing plane have waited for news for days, relatives gathered around a large screen television watching the Australian news conference. They leaned forward in their chairs, hanging on every word. Some sighed loudly.

Malaysia Airlines said it won't be sending representatives or family members to Perth unless the objects are confirmed as plane debris.

'The best lead we have right now'

The images of the objects were captured by satellite and were being assessed by the Australian Geospatial-Intelligence Organisation. The images were taken near the area of the southern Indian Ocean that has been scoured by search teams in recent days.

Although the total search area for the plane spans nearly 3 million square miles, a U.S. government official familiar with the investigation said the missing plane is most likely somewhere in the southern Indian Ocean.

"This is an area out of normal shipping lanes, out of any commercial flight patterns, with few fishing boats, and there are no islands," the official said.

Young cautioned the images may not be from the plane. There can be other debris out there, from ships, for example.

The objects were seen in the heart of what is known as the Indian Ocean Gyre. There is little to no oceanic current movement in the region and the area is notorious for trapping debris. It's one of the five major gyres in the world's oceans and is known to contain a "garbage patch."

"It is probably the best lead we have right now," Young said. "But we need to get there, find them, see them, assess them to know whether it's really meaningful or not."

The visibility in the area is poor, Young cautioned. "The weather is not playing the game with us," he said.

Planes arrive

A Royal Australian Air Force Orion aircraft has already arrived in the area, Young said, and three other planes are being sent there, including a New Zealand Air Force Orion and U.S. Navy P8 Poseidon.

The flight crew on the Poseidon say they're getting radar hits of "significant size," indicating something lying below the water's surface, ABC News reported Thursday.

ABC's correspondent David Wright, who is on board the aircraft, says the crew told him that the radar indicates that "there is something down there." But ABC cautioned that it is still too early to tell if the radar hits are related to the missing plane.

An Australian C-130 Hercules plane has been tasked by Australian authorities to drop marker buoys in the area, Young said.

"The first thing they need to do is put eyes on the debris from one of the aircraft," said aviation expert Bill Waddock. The buoys will mark the place and transmit location data.

The Malaysian Navy has six navy ships with three helicopters heading to the southern Indian Ocean to take part in the search, a Malaysian government source said.

'Every lead is hope'

"Verification might take some time. It is very far and it will take some time to locate and verify the objects," the Malaysian government source said.

Malaysia's Acting Transportation Secretary Hishammuddin Hussein told CNN he couldn't disclose the information the Australians shared with Malaysia. He said he hadn't seen the images.

But he added, "Air and vessels are going there. You know how big the area is. Every lead is hope. We have been consistent with our process and we want to verify properly."

Flight simulator probed

Other pieces of information related to the investigation into the plane's disappearance had emerged Wednesday.

Investigators looking at the flight simulator taken from the home of Capt. Zaharie Ahmad Shah, the pilot of the plane, have discovered that some data had been deleted from it, Hishammuddin said at a news conference.

What the revelation means is unclear. It could be another dead end in an investigation that has been full of them so far, or it could provide further evidence for the theory that one or more of the flight crew may have been involved in the plane's disappearance 12 days ago.

"It may not tell us anything. It's a step in the process," one U.S. law enforcement source told CNN. "It could be a very insignificant detail in the process."

Investigators have been looking into the background of all 239 passengers and crew members aboard the plane that vanished in the early morning hours of March 8 while en route from the Malaysian capital of Kuala Lumpur to Beijing.

Particular attention has focused on the pilot and first officer, but authorities have yet to come up with any evidence explaining why either of them would have taken the jetliner off course.

Hishammuddin didn't say what had been deleted, but simulation programs can store data from previous sessions for later playback. He also did not say who might have deleted the data.

Angry families want answers

The lack of progress has angered and frustrated families, who have accused Malaysian officials of withholding information.

Some family members staged a protest Wednesday at the Kuala Lumpur hotel where media covering the search are staying. Their efforts were cut short by security guards who removed them through a crush of reporters, dragging one as she screamed.

"I don't care what your government does," one woman shouted, referring to the Malaysians. "I just want my son back."

The agony of the wait is also being felt by families in Beijing, the scheduled destination for Flight 370. They gather daily for a briefing with officials.

Ye Lun, whose brother-in-law is on the missing plane, says every day is the same. He and his group leave the hotel in the morning for a daily briefing, and that's it. They go back to the hotel to watch the news on television.