Airplane crashes are rare. When they do happen, however, they are often deadly and people want answers as to why their loved ones lost their lives, and that is where black boxes come into play.
A black box is a device placed in an aircraft to make the investigation of aviation accidents easy.
There are two different flight recorder devices. The flight data recorder (FDR) preserves things like air speed, altitude, and fuel flow and has about 25 hours of recording storage. The cockpit (驾驶舱) voice recorder (CVR) preserves the recent history of the sounds in the cockpit, including the conversation of the pilots. However, a cockpit video recorder can store only two hours of voice recording. Both of them are mandatory on every commercial flight and are usually kept in the back end of an aircraft, where they are more likely to survive a crash.
Equipped with an underwater locator beacon (水下定位信标), if an aircraft crashes into water, the beacon sends out an ultrasonic pulse (超声波脉冲). Incredibly, the beacon is powered by a battery that has a shelf life of six years; once the beacon begins pinging (发出信号), it pings once per second for 30 days until its battery runs out. If a plane crash takes place on land and not on water, the locator beacons of the black box will not send out the ultrasonic pings, signaling the investigators to look for the unit around the crash site.
The term “black box” was a World War II British phrase, originating with the development of radio, radar, and electronic navigational aids in British and Allied combat aircraft (盟军战斗机). These often-secret electronic devices were literally encased in non-reflective black boxes or housings, hence resulting in the birth of “black box”.
These black boxes are of fluorescent (发荧光的) flame-orange in color. The recorders are bright orange so to make them more visually obvious after an accident. These are able to stand extreme heat, crashes and massive pressure. Before being put into use, they are examined repetitively in extreme situations to see if they can conduct the functions well.
12. If you want to know how high the plane was flying, you should check the ______.
A.the flight data recorder. | B.the cockpit voice recorder. |
C.an underwater locator beacon. | D.the data of the analysis of the examination. |
13. Which of the following is TRUE according to the passage?
A.The recorders are bright orange in that the color is obviously the most beautiful. |
B.The black boxes will be put into use after being examined by experts. |
C.The beacon sends out an ultrasonic pulse when the plane crashes in the mountains. |
D.The back end of the plane is least likely to be damaged in a crash. |
14. What is the main idea of paragraph 5?
A.How the black box got its name. |
B.Some latest advances in military. |
C.The black box will be taught in this new term. |
D.The cruelty of the world war II. |
15. What is the purpose of writing the passage?
A.To present the latest improvement in the black box. |
B.To make a brief introduction to the black box. |
C.To explain how the black box works. |
D.To advertise an advanced black box. |