Mumbai: The black box is a crucial tool in aviation investigations and is central to determining the cause of the recent Air India Dreamliner crash. Mint breaks down what it is, how it works and what’s next.

What is a black box?

A black box is a small machine that records all information about an aircraft during its flight. It helps investigators understand and investigate an aeroplane mishap. Despite the name, the black box is bright orange to aid in recovery efforts.

In the Air India crash, the Boeing Dreamliner had two such devices, one installed in the tail and the other in the nose. General Electric (GE) manufactured the combined flight data and cockpit voice recorder, which is called an “enhanced airborne flight recorder”.

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What is the origin of the black box?

Australian scientist Dr. David Warren invented the black box in the 1950s. They are built to withstand crashes, are resistant to fire and are able to withstand deep-sea pressure. It can withstand up to 3,400G force (or an impact equivalent to 3,400 times the force of gravity), temperatures of 2000°F (1100°C) and underwater pressure at 20,000 feet for 30 days. They also have backup batteries to keep recording even if the aircraft’s main power supply fails. It has been used in commercial aircraft operations since the 1960s, as these devices became mandatory globally for accident investigations and analysis.

What does a black box record?

The black box comprises a flight data recorder (FDR) and a cockpit voice recorder (CVR). The FDR records up to 1,000 parameters, including altitude, speed, engine performance, fuel status, hydraulic and electric system data and more, covering the last 25 hours of a flight.

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The cockpit voice recorder records the final two hours of the cockpit environment, including pilot conversations and radio communication with air traffic control. It also emits a locator signal for 30 days.

How is the data retrieved?

Following the 12 June Air India crash, one of the black boxes was recovered from the rooftop of a building at the crash site on 13 June, and the other from the debris on 16 June. The aviation devices were then taken to Delhi on 24 June, for analysis by India’s Aircraft Accident Investigation Bureau (AAIB).

As per international aviation rules (ICAO Annex 13), representatives from the aircraft and engine manufacturers, the black box maker, and the US National Transportation Safety Board (NTSB) must be present as observers during the data download process, said Captain Mohan Ranganathan, a former airline instructor.

What’s next?

So far, a team led by AAIB director general G.V.G. Yugandhar, along with experts from AAIB and the US NTSB, has begun extracting data from the black box. They safely retrieved the Crash Protection Module (CPM) from the front black box, which holds the actual data. The memory was accessed and data was successfully downloaded at the AAIB lab.

Analysis of the cockpit voice recorder and flight data recorder is now in progress.

They are expected to submit a preliminary report within 30 days of the crash. However, the jury is still out on whether any details behind the reasons leading to the crash will be revealed and the wait may be prolonged.