Air India Crash: How Long Does It Take For Black Box Details To Emerge? Learnings From Previous Incidents

One of the two black boxes of the crashed Air India flight in Ahmedabad, which led to the death of 241 people onboard on Thursday, has been recovered. The search for the other black box is underway as investigating teams look for clues about the cause of the deadly accident.

London-bound Air India AI171, a Boeing 787 Dreamliner aircraft, crashed in Ahmedabad on Thursday afternoon immediately after takeoff and burst into flames. The aircraft was in the air for 30 seconds after takeoff when it reached a maximum height of about 190 metres before descending towards Meghani Nagar area near the airport. It then crashed into the doctors' hostel of BJ Medical College, leading to a huge explosion.

The victims included former Gujarat Chief Minister Vijay Rupani, while there was a 40-year-old lone survivor who is undergoing treatment. A British national, Vishwash Kumar Ramesh, was seated on 11A and was able to escape following the crash.

According to Ramesh, he heard a loud bang as the plane struggled to gain altitude and then crashed. Everything happened so quickly that there was not enough time to understand what was going on.

Details are expected to emerge when the officials investigate the black box, a key tool used by aviation investigators to understand air accidents. It includes two main parts. The cockpit voice recorder captures voices, alarms, and background sounds like engine noise or switch movements. The flight data recorder tracks speed, altitude, direction, pilot actions, and system performance.

In the Ahmedabad crash, the officials are yet to recover the cockpit voice recorder. A report by the BBC cited experts to suggest that it could be an extremely rare double engine failure. The recovered black box will be sent to the Aircraft Accident Investigation Bureau, which will undertake further investigation.

Based on past incidents, while the initial assessment of the black box may be available within the first 24 hours of the crash, a detailed probe can take longer. A lot also depends on factors like the extent of damage to the device and the nature of the accident.

To start the investigation, officials take measures such as peeling away the initial protective measures and cleaning connections. A lot of measures are taken to ensure that the data is not accidentally erased in the process of recovery. From the device’s recordings, the files are downloaded and copied. To be clear, the data itself doesn’t mean anything but needs to be decoded from the raw files before being turned into graphs.

The whole process to generate an interim report can take weeks and even months. However, deeper investigations take a year or more to complete.