Black box : The flight data recorder

Black box first came into widespread use on commercial aircraft after World War 2. It was invented by Australian scientist Dr David Warren in 1958. In 1960, Australia was the 1st country to make Black box mandatory for all commercial aircraft. A black box, technically known as an Electronic Flight Data Recorder, is an orange-coloured heavily protected recording device placed in a flight. Any commercial aircraft is required to be equipped with a Cockpit Voice Recorder(CVR) and a Flight Data Recorder(FDR). It is these two items which we commonly refer to as a Black box. While they do nothing to help the plane when it’s in the air ,it is vitally important if the plane crashes as it helps crash investigators to find out crucial events that led to the crash. They are usually kept at the tail of an aircraft which is likely to survive a crash. It usually takes at least 10-15 days to analyse the data recovered from the black boxes. Black boxes are also used in vehicles other than planes like railways, cars etc.

Parts of the black box :
1. Flight Data Recorder – It keeps the track of every instruction made by the pilots and records things like airspeed, altitude, vertical acceleration and fuel flow.
2.  Cockpit Voice Recorder – It records the conversations in the cockpit and general noises in their vicinity such as audible warnings.

The federal Aviation Audio (FAA) requires them to be able to record 2 hours of audio. The previous requirement was 30 minutes but investigators found that they sometimes needed details from longer period before the crash.

Technology:

• Older black boxes used magnetic tape, a technology that was first introduced in the 1960s. Magnetic tape works like any tape recorder but is no longer in making as it leaves a bit of data on the tape and as airlines begin a full transition to solid-state technology.
• These days, black boxes use solid-state memory boards, which came along in the 1990s. Solid state memory boards are much more reliable than memory tapes as they use stacked arrays of memory chips so they don’t have moving parts. With no moving parts, there are fewer maintenance issues and a decreased chance of something breaking during a crash., and are stronger.
• Data from both the CVR and FDR is stored on stacked memory boards inside Crash-Survivable Memory Units (CSMUs) which are engineered to withstand extreme heat, jarring crashes and tons of pressure.
• To make black boxes discoverable in situations where they are under water, they are equipped with locator Beacons. These broadcast their location by sending out ultrasound signals for upto 30 days even when submerged as deep as 6,000 meters (20,000 feet).

Airplanes are equipped with sensors that gather data. There are sensors that detect acceleration, airspeed, altitude, flap settings, outside temperature, cabin temperature and pressure, engine performance and more. Magnetic-tape recorders can track about 100 parameters, while solid-state recorders can track more than 700 parameters in larger aircraft. All of the data collected by the airplane’s sensors is sent to the flight-data acquisition unit (FDAU) at the front of the aircraft. This device often is found in the electronic equipment bay under the cockpit. The flight-data acquisition unit is the middle manager of the entire data-recording process. It takes the information from the sensors and sends it on to the black boxes.

Black boxes are painted in a bright shade of orange. This coloring makes them far easier to locate amid the potentially considerable devastation of an aircraft’s crash site. It has reflective surfaces to increase their visibility. But their are certain cases like the Malaysian Airlines MH370 flight where they are not found. And they still lack video recording capabilities.

It is being tried to stream all of their essential data directly to a ground-based station in realtime which would eliminate the desperate search for a box that may have been destroyed in a crash, and will be more dependable.

Sources : http://www.iasa.com.au and Dristi IAS.