字幕表 動画を再生する 英語字幕をプリント following a plane crash. The search for survivors always comes first, but just as important is the search for answers. The why and the how often those answers are found in the black box. Since the sixties, all commercial airplanes have been required to have one on board. Now the name is a little misleading because they're actually orange. And when we're talking about a black box, we're talking about two different boxes, one being the cockpit voice recorder, the other being the flight data recorder. Together, they were anywhere between 20 to £30 and they have to be crash proof. Black boxes conserve. I've just about anything temperatures up to 2000 degrees Fahrenheit for our forces that are 3400 G's. Now that's 3400 times the force of gravity. They're waterproof, and they can save recorded data for two years. And it's a lot of data. The cockpit voice recorder records the crew's conversation and background noise by listening to the ambient sounds in a cockpit before crash, experts can determine if a stall took place, the rpm's of the engine and the speed at which the plane was traveling. When these sounds are cross referenced with ground control conversations. They can even help searchers locate a crash site. Then there's the flight data recorder. It gathers 25 hours of technical data from airplane sensors recording several 1000 discrete pieces of information data about the air speed, altitude, pitch acceleration, roll fuel and the list goes on and on. But to make sense of the data first, you have to find it not an easy thing to do when a plane crashes into the ocean. Both black box components are outfitted with underwater locator beacons, which self activate the moment they come into contact with water. They send pings once per second to signal their location and can transmit data from his deepest 20,000 feet for up to 30 days when their batteries then run out. But on land, there's no such pinging.