Here's how a black box reveals the cause of a plane crash

A black box is instrumental and crucial in determining what actually caused a plane crash. Had it not been for this equipment, there would be many unanswered questions in relation to countless air crashes which would still remain a mystery. But is that all there is to know about black boxes?

If you think a black box is referred to as such due to its colour, you're wrong. A black box is painted orange so that it is identified distinctly while rescue workers search for the equipment at the crash site, particularly underwater. It actually consists of two different pieces of equipment as well; the data flight recorder and the cockpit voice recorder. It is kept at the rear end of the airplane so that it has the best chance of surviving an air crash. 

The flight data recorder consists of important data pertaining to the speed, direction, altitude of the plane as well as how much fuel is present and whether the autopilot is on or not. It also stores the cabin temperature as well. It has the capacity to record 25 hours of data.

The cockpit voice recorder contains the voice recordings of the crew and the pilot in the cockpit. It also records emergency alarms, storm warnings, engine sounds, etc. At times, investigators are able to determine what actually caused an air crash just by listening to the sounds from the cockpit voice recorder. 

The outer casing of any black box cannot withstand a plane crash hence the data is stored inside the most important part of the black box, the memory unit, which has the ability to survive a crash. Memory boards containing all the relevant data are stored inside the memory unit, which is protected from heat by an insulation layer and steel titanium shell.  

Black boxes have to undergo crash tests before they are deemed ready to use. They are tested to withstand heat up to 1100 degrees Celsius and can withstand high pressure beneath sea water as well as aviation fuel. A beacon location transmitter is fitted onto some black boxes, which can send out pulses of ultraviolet sound. These pulses can be sent for a total of 30 days from 14,000 feet under the sea. 

It can take up to a few weeks and months for investigators to deduce data from a black box and come to the exact conclusion as to what caused an air crash. However, without the black box, it would be impossible to determine what actually caused an air crash.