Black box (transport)
The black box or flight recorder is the device that, mainly in aircraft, trains, ships and spacecraft, records the activity of the instruments and the conversations of The crew. Its function is to store data that, in the event of an accident, makes it possible to analyze what happened in the previous moments and establish its causes. Large commercial aircraft carry two black boxes, technically known as CVR (cockpit voice recorder) and FDR (flight data recorder).
Vessels have similar systems (derived from them) called Voyage Data Recorders (VDR)
The first flight recorders came into use at the end of the 1950s and were called black boxes, a name that lasted even after they were painted orange to make it easier to locate them after a long flight. accident. The origin of the name black box is unclear: some of the RAF prototypes were painted black, other prototypes were camera obscuras with photographic plates, and from a systems point of view, they were they behave like black boxes (focus is placed on their inputs and outputs).
The black box revolutionized the aviation industry
A black box or flight recorder is the device that, mainly in aircraft and motor cars or train locomotives, records the activity of the instruments and the conversations in the cabin. Its function is to store data that, in the event of an accident, allow analysis of what happened in the previous moments. According to international aviation regulations, these devices are now mandatory on all commercial flights as they record travel data and are key in investigations into plane crashes. Thanks to them, nine out of ten accidents can be explained. That is why so much effort has been put into the Malaysia Airlines flight case MH370 lost in March 2014 on a flight from Kuala Lampur, the capital of Malaysia, to Beijing, the capital of China.
As with so many other sophisticated inventions, it does not have a single inventor, but the first black box prototype dates back to 1939 and was designed by French engineer Francois Hussenot. It was a rudimentary box made of photographic film calibrated with mirrors. Sensors on board fired flashes onto the photographic film, thus recording the history of the flight. Mindful of the importance of his invention, Hussenot is said to have hidden the box from the invading Nazi army of his homeland, burying it near a beach on the Atlantic Ocean in June 1940. And as with so many technological advances, warfare perfected technology., which was extended to commercial flights around the world. After World War II, some devices used photography and others printed the data on aluminum coils.
The first flight recorders came into use at the end of the 1950s and were called black boxes, a name that lasted even after they were painted orange, this to facilitate their location after an accident. The denomination of black boxes comes, as in other situations (such as a black day) from the fact that when black boxes become necessary, it is because a plane crash has occurred.
Audio recorders
The black box itself is the work of Australian David Warren. In 1953 this chemist and aviation engineer was asked to help discover the cause of a series of plane crashes. Experts were trying to understand why several Comet planes had crashed without explanation, casting doubt on the future of commercial flight. I kept thinking to myself... If we could recover those last seconds he said in a 1985 interview quoted by The New York Times, it would save a lot of discussion and uncertainty . A year later, Warren proposed installing a recording device in the cockpit, and by 1958 he had produced the prototype Flight Memory Unit. That first version was slightly larger than an adult's hand, but capable of recording about four hours of cockpit conversation and command readouts. Warren's version recorded sound on a magnetized steel coil. To Warren's surprise, the device was rejected by aviation authorities, who found it of "little direct and immediate use for civil aircraft," while pilots called it a "Big Brother." #3. 4; (Big Brother) who would spy on his work.
When Warren brought the invention to the UK, it was enthusiastically received and after a BBC report on the device, manufacturers began to take an interest in the project. Meanwhile in the United States, there was already research on the device and in 1960, the first steps were already taken to make the devices mandatory. In the mid-1960s, flight recorders - data and voice - were required for commercial aircraft. Now that flight computers have replaced magnetic tape, the devices can record more data and are much more likely to survive an impact. It must have a label with the letters at least 2.5 cm high that read: "FLIGHT RECORDER DO NOT OPEN" in english and french.
Current Registrars
Today's loggers use flash memory chips, capable of storing data for several years without power. Currently, they digitally record the last two hours or the last thirty minutes (depending on the model) of all the conversations carried out in the cockpit, both those carried out by the pilots and those of the environment, which are captured by means of a microphone normally installed in the upper panel (overhead) and that records all the sounds that are produced in the cabin (conversations, audible warnings from the plane, etc.). These recorders also contain circuit cards that process and compress the data, although only the memory chips are enclosed in the case's shock block. That block is covered in thick steel armor to resist crushing on impact. Beneath the steel is a layer of thermal insulation designed to protect the memory chips from the fires that often occur after a reactor accident.
All large commercial aircraft carry two boxes: the Cabin Voice Recorder or CVR (Cabin Voice Recorder - CDR) which records the conversations of the flight crew and the sounds coming from the cockpit, and the flight data recorder (Flight Data Recorder - FDR), which records the aircraft's altitude, airspeed, heading, and other instrumental readings. Given the importance of this information, the recorders are designed to resist considerable accelerations, in addition to being located in places that tend to be less punished by an impact, such as the tail of the plane.
The list of instrumental readings to be stored was recently expanded and it has also been proposed that each cockpit voice recorder be equipped with a backup power supply so that it can continue to function even if the aircraft's electrical circuits fail.
The most modern black boxes have inputs to store video, giving the possibility of recording the actions that occurred in the flight deck in the moments prior to the accident.
Certification test
The certification tests that are carried out to verify that they are prepared are the following:
- Impact test: a gas gun launches the logger against an aluminium target, producing a maximum force of 3500 kilos.
- Test resistance to penetration: drops on the device, from three meters high, a mass of 225 kilos provided with a tempered steel tip.
- Static crushing test: an actuator applies a compression of 2300 kiloponds.
- Deep dive test: the registrar must resist 24 hours in a chamber full of pressured marine water.
- ignition test: it is submitted to flames of 1.100 °C.
Deficiencies and proposals for innovation
One of the biggest shortcomings of black boxes is the possibility of loss -especially in accidents that occur at sea- or total destruction. To remedy these deficiencies, innovations have been proposed such as the development of floating black boxes, self-ejecting in the event of an accident, equipping them with a GPS locator, or with the capacity to transmit data via satellite as they are recorded. Box technology Self-ejecting black was initially used in military aviation and since 2015 in some commercial aircraft.
The possibility of using data transmission systems via satellite in real time has been observed due to the danger that people or companies outside the authorities in charge of accident investigation could access the information to manipulate or use it abusively.
Sea navigation
The installation of a Voyage Data Recorder (RDT or VDR) is currently mandatory on all newly built ships, with the exception of non-passenger ships whose gross tonnage is less than 3000 tons. There are simplified versions (S-VDR) for smaller vessels.
The philosophy is similar to the case of aircraft: the sounds captured in the control bridge and the ailerons (a kind of "balcony" that the bridge has, are recorded, port and starboard), audio from the VHF system and, on the other hand, control data such as rudder angle, engine speed, watertight door status, along with data from GPS, echo sounder, radar, or others are recorded. Everything is recorded in a hermetic capsule that periodically overwrites the data, always leaving the last 12 hours (48 hours according to MSC.333(90)) prior to the power cut, always legible, which must be kept for a minimum of 30 days afterward. Pods can be fixed to the hull or released by hydrostatic releases such as emergency beacons and life rafts.