A black box is a flight data recorder (FDR), nowadays fitted on each and every plane. They record dozens of parameters collected several times per second as well as voices and sounds in the cockpit. In the unfortunate event of a plane crash, retrieving the black box is a priority for investigators to determine the cause of the accident.
1. Orange is the new black
Although they are commonly known as black boxes, FDRs are in fact bright orange. 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. These often-secret electronic devices were encased in metal boxes painted with non-reflective black paint to protect the metal and prevent rust.
When FDRs were mandated by leading aviation countries in 1967, the decision was made to change their colour to fluorescent flame-orange to be easily recognisable at a crash site. Fluorescent flame-orange box did not seem to catch on with the public, so the name black box stuck.
2. The invention of the black box
Australian scientist David Warren is considered the inventor of the first flight and voice recorders for the commercial aviation industry, however, earlier designs were put forward by François Hussenot and Paul Beaudoin at the Marignane flight test centre in France in 1939. Their “type HB” flight recorder essentially generated photograph-based flight recorders, because the record was made on a scrolling photographic film.
In 1947, Hussenot founded the Société Française des Instruments de Mesure with Beaudouin and another associate, so as to market his invention, which was also known as the “hussenograph”. This company went on to become a major supplier of data recorders, used not only aboard aircraft but also trains and other vehicles.
3. Stronger and better
During World War II, in the UK, Len Harrison and Vic Husband developed another form of flight data recorder, setting the basis for the modern black boxes. Their model could withstand a crash and fire to keep the flight data intact, being able to withstand conditions that aircrew could not.
A few years later, in 1942, Finnish aviation engineer Veijo Hietala created the first modern FDR, called Mata Hari. This black high-tech mechanical box was able to record all important details during test flights of fighter aircraft of the Finnish.
4. The first FDRs for commercial aircraft
Until the 1950’s, FDRs were mainly used on military aircraft. In 1958, David Warren built the first combined flight data and cockpit voice recorder (CVR), designed with civilian aircraft in mind, explicitly for post-crash examination purposes.
5. Black boxes become mandatory
Australia was the first country to make black boxes mandatory, after the crash of Trans Australia Airlines Flight 538 in 1960. Just 4 years later, the United States passed the first rules requiring all turbine and piston aircraft with four or more engines to have CVRs by 1 March 1967.
By that year, most countries around the world made FDR/CVR devices mandatory, in their bright orange boxes, sitting in the tail of the plane, where they have the best chance of survival in the event of a crash and where they are still placed today.
6. Room for improvement
The disappearance of Malaysia Airlines Flight 370 in March 2014 highlighted the need for improvement of black boxes. Despite the already fitted underwater locator beacon, the aircraft, or its black box, were never retrieved.
This led authorities to ask for live streaming of data from the aircraft to the ground. Experts also requested for the underwater locators to have longer battery life and wider range. Moreover, they called for the implementation of a back-up recording device to be ejected from the aircraft before impact.
An opinion in the Aviation Week magazine from March 2019 described again the need for live streaming flight data: “Live flight data streaming as on the Boeing 777F EcoDemonstrator, plus 20 minutes of data before and after a triggering event, could have removed the uncertainty before the Boeing 737 MAX groundings following the March 2019 Ethiopian Airlines Flight 302 crash.” The measure remains to be implemented.