Starting right now on ABC's "This week" -- rampage. He came back. With a gun. And opened fire. The moment of attack. The heros who saved lives. This morning, we're at fort hood with breaking details... See More
Starting right now on ABC's "This week" -- rampage. He came back. With a gun. And opened fire. The moment of attack. The heros who saved lives. This morning, we're at fort hood with breaking details and taking on the critical questions. Plus, culture of coverup? I don't have the complete facts. That is incredibly frustrating. The head of gm grilled over a massive car defect linked to multiple deaths. Should you feel safe behind the wheel? And campaign cash. Keep our eyes on the prize. The supreme court strikes down limits on donations. Will it protect your freedom of speech, or is our democracy now for sale? From ABC news, "This week" with George stephanopoulos begins now. Good morning. I'm Martha Raddatz in fort hood, Texas, a tight-knit community reeling from another horrific mass shooting this week. The second in five years. We'll have complete coverage of the story here shortly, including the latest on the investigation. But first, as we come on the air, breaking news in the hunt to find that missing Malaysia air 777. We're learning that an Australian ship may have heard the pingers from flight 370's black boxes just hours ago. Just yesterday, the Chinese reported they too were reporting so-called acoustic events. It's a critical time in the search. The batteries powering the pingers could die today, 30 days after the plane disappeared. We have two reports this morning. Beginning with Clayton Sandell in Australia. Clayton. Reporter: Good morning, Martha. That's right. After the Chinese Navy ship reported hearing two pulse signals that are consistent with what you would expect to hear from an airplane's black boxes, the Australians wanted to send their own ship to check it out. It's the ocean shield and has underwater search gear that belongs to the U.S. Navy. But now that ship 350 miles from the Chinese vessel is staying in place because it has a lead to chase. They have now heard a third mysterious underwater sound. Keep in mind the Australians leading the search say they are important leads, but they cannot verify if they are connected to Malaysia 370. There's another development this morning. The high-priority search area shifted again. That's because of a new analysis of those last communications transmitted from the plane to a satellite, now suggesting the Boeing 777 was going faster than first thought. That would put it going into the ocean near where the Chinese picked up their signal. Now a british ship is expected to arrive early Monday to determine if this is something or another false lead. But right now, it is the most promising lead in this search that has now stretched nearly a month. Martha. Thanks, Clayton. Investigators have found no sign of the jet, they are learning lessons that could prevent another missing plane mystery like this one. Here is ABC's David Curley. Reporter: Dozens of flights, a flotilla of ships, hundreds of partly sunny of eyes and still not a piece of debris from the missing plane has been recovered. Still, the mystery of flight 370 is already providing lessons. The most obvious, how in 2014 can we not know where a jetliner is? In a world where our every move seems to be tracked, we cannot let another aircraft simply disappear. Reporter: So lesson number one. Keeping track of aircraft. Should we install gps transmitters in all commercial aircraft which would transmit to a satellite where they are every few minutes? It's unacceptable. The fact that, you know, you have gps in a sub-compact car on the highway and not on board a commercial aircraft with 300 people. Reporter: A delayed FAA traffic control system would have the gps signal. But they say it is time for the gps. I think given the reality we have lost an airplane and have no idea where it is, we have to retro-fit the fleet. Reporter: Lesson two. What about those black boxes? This morning the batteries will start fading. Some suggest instead of just keeping all the data on the boxes in the aircraft, why not stream or burst the data to satellites on the aircraft's performance as well? In many cases they are not recovered, or are damaged beyond repair. Reporter: But broad band streaming to a satellite is not cheap. We don't have enough satellites to take the huge a. -- Amount of bandwidth. We have 93,000 flights per day, just in half, that is a tremendous amount of data. Reporter: Lesson three, who's in charge? Current the country where the flight crashes, or the country of the operate in international waters, heads the investigation. But as the Malaysians have shown with the conflicting and slow release of information, not all countries may be up to that task. Yes, it was disabled before. We cannot determine exactly what -- There's no way of putting it, they have bungled it from the beginning. Reporter: Why not an international investigative body? It's clear we need that. Because the first few hours of these investigations are so critical. Reporter: Finally, the fourth lesson. Some airlines appear unskilled at family relations. Chinese relatives of those on board have wailed and protested. And learned their loved ones were lost in a text message. When families are grieving and there's a loss of a loved one or loved ones, you can't leave this to chance, can't make it up while you go along. Reporter: Four lessons with so many more in the black boxes on the bottom of the Indian ocean as the locater signals start to fade. For "This week," David Curley, ABC news, Washington.
This transcript has been automatically generated and may not be 100% accurate.