17 years ago, Brazilian commercial aviation experienced a hiatus of serious air accidents. This fast was unfortunately broken with the VOE ATR 72 crash, in Vinhedos (SP), claiming the lives of 62 people. In the midst of Brazil's achievements at the Olympics, the sad sinister took over the headlines in national journalism, bringing to light several questions and 'reviving' issues. Among them, the famous and infamous black boxes.
In every air accident, the black box topic is always highlighted, after all, voice and data recorders are popularly considered the key to the causes of the occurrence (although investigators investigate much more than that). But after all, how did this important piece of equipment come about? And how does it work?
First of all: black box is a popular nickname for a set of data and voice recorders – as mentioned above – which, when installed on an aircraft, record the pilots' conversations in the cockpit and the plane's trajectory data, as well as the functioning of systems and engines. Technically, they are called Flight Data Recorder, or FDR, and Cockpit Voice Recorder, or CVR.
Although they are called a black box, the CVR and FDR are painted fluorescent orange. The painting is to make it easier for investigators and rescue teams to find equipment at the scene of the accident.
How does the black box appear?
The nickname emerged during the Second World War, specifically in England, related to the development of radar, radio and air navigation systems. Such equipment was highly secret and enclosed in black boxes. Still at the time, the air forces of the United States and England experimented with the use of data recorders on their aircraft, informally giving the equipment its nickname.
The flight data recorder appeared at the same time as the conflict, in 1939, but at the hands of the French François Hussenot and Paul Beaudouin, who carried out the first experiments using photographic film using the so-called HB Recorder. During the war, Hussenot and Beaudouin started using metal tapes on an aluminum reel to record information, since this material is much better suited to resist accidents.
In parallel, in Finland, a device called 'Mata-Hari', created in 1942 by engineer Veijo Hietala, is considered the first modern FDR. The instrument, which was also mounted on a black box, was used to record data from test flights on fighter aircraft.
On the other hand, the CVR only emerged around 1958, an initiative by Australian David Warren from Aeronautical Research Laboratories (ARL). Years earlier, Warren participated in investigations into accidents involving the de Havilland Comet, the first commercial airliner powered by jet engines. Despite technological advances, the Comet suffered several accidents and investigators had no way of getting reports from the crew.
Warren then developed a prototype, initially called the Flight Memory Unit, that used a magnetized steel coil to record up to four hours of cockpit conversations and eight instrument readings, four times per second. The equipment was not well liked at the ARL, but during a visit, the Secretary of the British Air Registration Board, Sir Robert Hardingham, met the recorder and recognized the instrument's importance for elucidating air accidents.
How a modern black box works
The modern FDR and CVR were developed from David Warren's Flight Memory Unit. Together, they are called the Data and Voice Recording System and are enclosed in an orange casing, made of steel and titanium to ensure that information is not lost in the event of an accident. Modern black boxes can withstand temperatures exceeding 1000ºC and impacts of up to 3400 times the force of gravity.
When black boxes are found at the scene of an accident, investigators collect the equipment for a laboratory. The recorders are carefully opened and the data is ed to a secure computer, where it will later be analyzed.
In Brazil, the body responsible for this work is the Aviation Accident Investigation and Prevention Center, or Cenipa, an organization of the Brazilian Air Force. Headquartered in Brasília (DF), Cenipa works with the National Civil Aviation Agency (ANAC) to investigate the causes of air accidents and prevent new occurrences of this type.
In the case of the accident with VOE Flight 2238, Cenipa found the ATR 72 black boxes on the same day as the accident. The following day, the recorders were taken to the Flight Recorder Data Reading and Analysis Laboratory (LABDATA). Three days later, the FAB confirmed that the data had been extracted from the black boxes by a specialized team.
