The structure of an airplane is very complex, and the black box is only a very small part of it, but its effect is huge. If the airplane is safe, normal operation, then the black box is simply as a record of the equipment present in the aircraft. Once the aircraft faults, and even serious to the crash, then the black box is to give us a detailed study of the aircraft faults and causes of the crash only way. So, the black box is actually "horse cannon", as long as the accident, in order to play its due function. Now the data in the black boxes of many non-accidental airplanes are copied out and used as reference tutorials for flight training.
So after all this, we must be very confused, what is the black box? The black box is actually one of the specialized electronic recording devices for airplanes. Generally there are two black boxes, one is the cockpit voice recorder, the other is the flight data recorder. All mechanical parts of the airplane and electronic instrumentation are equipped with sensors and black box connection, so the black box can record the data of various instruments.
Black box is not actually black, why still called black box?
Although we manage this flight parameter recorder called black box, but its surface is not black, most of them are red, orange and so on very bright colors, some of the black box shell will be affixed with reflective strips, and wrote "FLIGHT RECORDER, DO NOT OPEN (Flight Recorder, Do Not Open)". DO NOT OPEN". This is so that in the event of a crash, we can quickly find the black box through the bright surface color.
To know the origin of the title of the black box, we have to look at the development of the black box.
In 1954, people conceived the idea of installing a sound recorder in the cockpit, when all the electronic instruments in the airplane were placed in a black square box of uniform size and shape.
In 1957, the FAA mandated that all aircraft weighing more than 9.09 metric tons must be equipped with these enhanced protection flight recorders.
Eight years later, the FAA decided to paint the black boxes bright red or orange so that the eye-catching surfaces would be easier to find in the event of a plane crash.
By 1965, almost every airline in the world had switched to colorful flight recorders, but the name remained the black box.
Black Boxes
Black Boxes are usually installed in the rear of the airplane, specifically under the rear vertical tail. There is an auxiliary power unit on this side of the vertical tail, and the black box is placed next to it. As scientists analyze a number of flight accidents, found that the tail part of the aircraft is not easy to damage, and this side of the cable in addition to very few cumbersome instruments, so the black box will be installed here. If an accident occurs, the black box can be saved to a higher degree, and the data can be taken out to analyze the accident.
The importance of the black box
First of all, the black box is a device that records flight data and cockpit calls, which can record the flight data of 25 hours before the airplane stops operating as well as communication recordings ranging from 30 minutes to 2 hours. The flight data includes flight altitude, speed, heading, climb rate, descent rate, acceleration status, fuel consumption, landing gear release, Greenwich Mean Time, aircraft system operating conditions and engine operating parameters, etc. The communication recordings are mainly to record the cockpit captain, co-pilot and crew call information.
All the air accidents in the world are analyzed by the black box, so it has become a witness to the air accidents and "lessons learned" to prevent the same accidents from happening again, and to better adopt safety measures. Although the black box is usually inconspicuous, but it is a very important part of the airplane, but also the only important parts of the airplane after the accident.
Black boxes were widely used in military airplanes during World War II. After World War II, the black box began to be applied to civil aviation aircraft. Since then, the black box has officially become a popular recording device. Then, let's take a look at the black box has been updated into what kind of.
Before the emergence of black box
In 1939, French aeronautical engineers Francis Yusno and Paul Baudouin invented a recording device, which can record the speed and altitude of the airplane and other most important information on the 88mm film with the principle of similar photography. After landing and take out the film, you can recover the situation during the flight. However, the film is a one-time use, the cost is very high, and this equipment is only applicable to the smooth landing of the aircraft, if the aircraft fall will destroy the film, so this recording method is only used in the new model of aircraft test flight.
The first generation of black boxes
During World War II, British engineers improved the flight parameter recording equipment, using a steel needle to inscribe the curve of various parameters on the copper foil. This way, even if the plane catches fire or crashes, the data can be retrieved. However, the copper foil is heavy, the amount of data recorded is also very limited, the price is not expensive, so it is only used in military aircraft. This is the first generation of black boxes, which can only record five flight parameters such as heading, altitude, airspeed, vertical overload and time.
The second generation of black boxes
In 1956, the first flight data recording device for civil airliners was born in Australia. Its inventor, Dr. David Warren, invented the second generation of the improved black box while researching aviation fuel. The operating principle of the new version of the black box is similar to that of a general magnetic tape player, but a protective shell with the ability to resist impact and fire has been added to the outside of the tape player. The second generation of black boxes are generally able to record dozens of parameters, and together with the presentation of the cockpit audio recorder.
Third-generation black box
Third-generation black box appeared in the 1990s. With the rapid changes in microelectronics technology, the black box began to use semiconductor memory to record data. The third generation of black box record parameters are generally in the hundreds, the function has been from the flight accident query, gradually extended to the daily pilot monitoring, aircraft fault diagnosis and maintenance.
Modern black box
The new generation of black box can record video information, the number of recorded parameters are also up to a few thousand, and can be through the satellite and other data chains to transmit important data of the black box at regular intervals. However, due to the communication bandwidth and signal blind spots as well as the impact of the climate environment, real-time data transmission methods can not completely replace the effect of the traditional black box. In addition, a new type of casting black box has also appeared, it can be actively separated from the body of the aircraft when it crashes, and has the water floating and radio, satellite positioning function.
With the continuous improvement of people's demand for the use of aviation flight, whether it is a military aircraft or civil aviation, the black box of this equipment is also very frequently updated. In a short period of more than 60 years has been updated four or five generations of black boxes. The previous black box can only record 5 parameters, the error is very large, now the black box can record 2 hours of CVR sound and 25 hours of FDR flight data, has significantly improved the accuracy of the analysis of air accidents and accidents.
In addition, the U.S. Transportation Safety Board also recommended the installation of a third black box in the aircraft: in addition to recording flight parameters and cockpit sound, through a camera, the cockpit of the real-time picture recorded, in order to better analyze the cause of the accident.
Development continues: "cloud" box is the future
Of course, the development of the black box is still ongoing, and the black box has accepted a new mission. Many of the technologies used in the black box are still based on ideas from the last century, such as the ultrasonic pulse signals that are emitted after an airplane enters the water, and the short life of the signaling batteries. Malaysia Airlines flight MH370 and Air France in 2009, two air crashes, let us find in the search for the black box of the shortcomings, especially after the crash black box into the sea, the search is even more difficult. So now the loudest call is to let the black box to participate in the "cloud", so that the data can be transmitted in real time, so that the future of the crash and accident analysis will be more simple, and do not need to search for the black box trouble.
While it's nice to imagine, there's still a lot of resistance to the idea of a "cloud" box. On a technical level, it is certainly possible to transmit black box data to the "cloud", but there is still the question of whether uploading the calls would compromise personal privacy. Also, there are 93,000 flights a day around the world, so the cost of uploading and storing so much data would be too high.
If an airplane is involved in a crash and it crashes, you need to analyze the exact cause of the crash and find the black box and interpret the data and recordings inside. But how can we find the black box?
Black box on land: relatively less difficult to retrieve
Once an airplane has suffered an air crash, the location of the crash is on land, and the search and rescue team can search for the black box according to the specific location of the plane crash. Because the black box is not able to send radio signals, so the retrieval work on land is mainly rely on the search and rescue team manpower search. The black box has a brightly colored exterior, and the search and rescue teams can search for the black box based on this feature, which is the only way to retrieve the black box on land.
Searching for the black box on land, sometimes the crash site is in the mountainous area, because the transportation and personnel to enter the more troublesome, need to enable the search helicopters and other mechanical units to help, so the retrieval of the work will be more difficult.
Black box in the water (mainly in the sea): relatively difficult to retrieve
The most complicated, is the aircraft crash in the water, which is very difficult to retrieve the black box. Of course, air crashes that occur in water are in the sea in most cases. The sea may seem calm, but there are a lot of undercurrents and currents below sea level, which means that the water is actually in constant motion.
When an airplane crash occurs, as soon as the underwater beacon added to the exterior of the black box touches water, the water will short-circuit its wiring, and the buzzer will emit an ultrasonic pulse at a frequency of 37.5kHz, which can automatically last for 30 days. This sound is clearly distinguishable even underwater, 8 kilometers away from it. 30 days after the battery is depleted, the signal will also follow the disappearance.
But because the ocean is deep and bottomless, and the terrain in many places is uncertain, it is likely to fall into a very deep trench, or be washed elsewhere by ocean currents and undercurrents in the water, which will increase the difficulty of searching for the black box, so far the black box of Malaysia Airlines Flight MH370 has not been found. Also, the crash site of Malaysia Airlines MH370 is indeterminate, in the sea can only use sonar systems, detectors, and in a certain area to detect, search an area and then change the next area, the workload is too large.
Of course, there is another possibility, that is, before the plane crashed into the ground, a serious explosion, resulting in damage to the black box, so there is no possibility to retrieve the black box.