Air India plane crash: What is black box? How does it help investigate cause of aircraft accidents?

Investigators involved in ascertaining the cause of the tragic Air India plane crash have found the black boxes from the accident site in Ahmedabad. The black box is considered a key instrument in aircraft crash probes as they hold crucial flight data. But what is a black box, and how does it help investigate the cause of aircraft accidents? Let's find out in this article.

Is black box actually black?
Most commercial airplanes today come with two black boxes, comprising a Cockpit Voice Recorder (CVR) and a Digital Flight Data Recorder (DFDR). In some aircraft -- like the Boeing 787 Dreamliner -- the two recorders are integrated into a single unit.
While they are called black boxes, the equipment is not actually black in colour. In fact, the boxes are painted bright orange so that they are easier to spot after plane crashes. The black boxes are made to survive extreme conditions, including explosions, fire, and deep water. It is made of strong substances such as steel or titanium. The boxes are strategically placed in highly-protected areas of the aircraft, mostly at the tail end, where the impact of a crash is often the least.

What does black box record?
Black boxes are key to investigating airplane crashes as they can preserve a range of crucial data. The Cockpit Voice Recorder or the CVR records radio transmissions and other cockpit sounds, including conversations among pilots and noises in the engine. And, the FDR records over 80 different types of information, such as flight altitude, speed, vertical acceleration, autopilot status, and so on. All this information can collectively help reconstruct the scene leading up to a plane crash. It usually takes between 10 to 15 days to analyse the data recovered from the black boxes after a crash.

What happened in Ahmedabad?
On June 12, An Air India plane carrying 242 people -- 230 passengers and 12 crew members -- crashed moments after taking off from the Ahmedabad international airport, killing almost everyone on board. The accident marked one of India's deadliest aviation accidents ever. The plane crashed in a residential area close to the airport and killed dozens others on the ground. Ramesh Viswashkumar, a 40-year-old British citizen of Indian origin, is the sole survivor of the tragic incident.