Now that Malaysia Airlines flight 370 is confirmed lost in the southern Indian Ocean, focus is turning to the retrieval of the flight's "black box".

The US has sent a black box locator to the search area, with less than two weeks to go until these crucial pieces of equipment stop transmitting.

Here are some things you might not know about black boxes:

1. They're not black

Black boxes are the same colour as the Golden Gate Bridge in San Francisco ... kind of. They are a tone of what's known as international orange, which is a set of three colours used in aerospace and engineering to distinguish objects from their surroundings. The Golden Gate Bridge is a darker shade, while the international orange used for black boxes is much brighter.

The tone of international orange used to paint the Golden Gate Bridge is most closely matched by Pantone colour 180. [Photo/AFP]

2. A 'black box' comes in two parts

The "black box" is made up of two separate pieces of equipment: the flight data recorder (FDR) and a cockpit voice recorder (CVR). They are compulsory on any commercial flight or corporate jet, and are usually kept in the tail of an aircraft, where they are more likely to survive a crash. FDRs record things like airspeed, altitude, vertical acceleration and fuel flow. Early versions used wire string to encode the data; these days they use solid-state memory boards. Solid-state recorders in large aircraft can track more than 700 parameters.

The black boxes from the Asiana plane that crashed short of the runway at San Francisco airport on July 6, 2013. [Photo/Twitter: @NTSB]

3. They were invented by an Australian

Dr David Warren's own father was killed in a Bass Strait plane crash in 1934, when David was just nine years old. In the early 1950s, Dr Warren had an idea for a unit that could record flight data and cockpit conversations, to help analysts piece together the events that led to an accident. He wrote a memo for the Aeronautical Research Centre in Melbourne called "A Device for Assisting Investigation into Aircraft Accidents", and in 1956 produced a prototype flight recorder called the "ARL Flight Memory Unit". His invention did not get much attention until five years later, and the units were eventually manufactured in the UK and US. However, Australia was the first country to make the technology compulsory.

Black Box inventor talks about his invention. [Video/ABC News]

4. Experts don't call them "black boxes"

The term "black box" is favoured by the media, but most people in the know don't call them that. There are several theories for the original of the name "black box", ranging from early designs being perfectly dark inside, to a journalist's description of a "wonderful black box", to charring that happens in post-accident fires.

Black boxes are normally referred to by aviation experts as electronic flight data recorders. Their role is to keep detailed track of on-flight information, recording all flight data such as altitude, position and speed as well as all pilot conversations. It is common for many civil airliners to have multiple devices to carry out these tasks so that information can be gathered more easily in the event of a failure. In most instances, they are used to help in the diagnosis of what may have been the likely cause of an accident.

Source: http://www.abc.net.au/news/2014-03-26/black-box-flight-recorders/5343456

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