Air India crash probe: From black box retrieval to AAIB’s preliminary report — a timeline of key events

While the initial report came under the scanner for being worded beyond the mandate and giving additional details, but selectively, chief Yugandhar said: “The purpose of the AAIB’s investigation and preliminary report is to provide information about ‘WHAT’ happened… At this stage, it is too early to reach to any definite conclusions. The investigation…is still not complete. The Final Investigation Report will come out with root causes and recommendations,” The full report is expected in about a year’s time.

As the AAIB-led investigation continues to be watched globally, here’s a timeline of key events in the probe so far:

📌June 12 – The AI-171 crash

On June 12 (Thursday), the Boeing plane—operating flight AI 171 from Ahmedabad to London Gatwick—crashed moments after take-off, killing 260 people, including 241 of the 242 on board and 19 on the ground. According to the 15-page report, the flight lasted “around 30 seconds” between lift-off and crash.

This was the worst aviation disaster involving an Indian airline in at least four decades, and the first fatal crash of 787 Dreamliner, Boeing’s latest generation wide-body aircraft.

📌June 13 – Enter AAIB, rear black box found

-Aircraft Accident Investigation Bureau (AAIB) launches an investigation into the Air India crash.

-The aft Enhanced Airborne Flight Recorders (EAFR) or the rear black box from the tail section of the plane is found from the rooftop of the BJ Medical College hostel mess building. It had suffered extensive internal thermal damage, as per officials.

📌June 14 – First aviation ministry briefing

Two days after the crash, the Ministry of Civil Aviation (MoCA) held a briefing where no questions were taken. Up until the release of the official preliminary report, there were just a few press releases on the status of the probe

📌June 15 – NTSB team arrives from US

The next day, a team led by a NTSB representative including those from Boeing, GE and Federal Aviation Administration (FAA) arrived in Ahmedabad and participated in the on-site investigation. A team of officials from AAIB’s team from the UK also arrived and visited the site with Yugandhar, the initial report specifies.

📌June 16 – Second black box found

The second black box unit (the forward EAFR) is also recovered from debris at the crash site near Ahmedabad’s Sardar Vallabhbhai Patel International Airport. It was burnt and covered in soot.

Two black boxes from General Electric Co (GE.N), one in the aircraft’s front and another at the rear, are installed on Boeing’s 787 jets, as per news agency Reuters. Both contain a cockpit voice recorder and a flight data recorder with the same sets of data.

📌June 24 – Black boxes reach AAIB HQ

Both EAFRs are transported from Ahmedabad to the AAIB’s facility in New Delhi.

The data from damaged flight recorders was downloaded by the AAIB after sourcing ‘Golden Chassis’ and relevant download cables from the DGCA and other Accident Investigation Authorities, the report states.

Here, the required ‘Golden Chassis’ (Identical EAFR unit) and Download cables were sourced from the US via the NTSB on June 23.

The downloaded flight data contained approximately 49 hours of flight data and 6 flights, including the event flight.

📌July 12 – AAIB’s initial probe report releases

The findings of the preliminary investigation report released by the AAIB provide the most detailed account of the incident on June 12.

It revealed that the aircraft’s engine fuel control switches transitioned from ‘RUN’ to ‘CUTOFF’ position within a second of each other moments after lift-off. To be sure, the report doesn’t mention that the fuel control switches — which allow and cut fuel flow to the plane’s engines — moved physically, and uses the term “transitioned” to describe the change of mode from RUN to CUTOFF. It also does not state these were moved by either of the pilots.

From the cockpit voice recorder data, the preliminary probe report notes that one of the pilots asked the other why he cut off the fuel, to which the other pilot responded saying he did not. The pilot flying was co-pilot Clive Kunder, while pilot-in-command Sumeet Sabharwal was pilot monitoring for this flight.

The report also said there were no recommended actions to Boeing or GE at this stage, indicating that a fault in the aircraft or engines was unlikely.

📌July 17 – AAIB chief releases statement

In an appeal issued on Thursday, AAIB Director General Yugandhar urged the public and the media to “refrain from spreading premature narratives” around the ongoing investigation. He also said that sections of the international media are “repeatedly attempting to draw conclusions through selective and unverified reporting”, and termed it “irresponsible” as the investigation is still on.

Meanwhile on this day, The Indian Express reported that the investigators were examining the history of technical snags and the possibility of system malfunction that can impact the FADEC’s (Full Authority Digital Engine Control) Engine Control Unit (the brain of the aircraft) to trigger “uncommanded” actions.

📌July 19 – NTSB chief on crash probe media report

Urging everyone to avoid speculation, the head of the US probe agency Jennifer Homendy termed recent media reports surrounding the probable causes of the crash as “premature and speculative”.

This comes close on the heels of reports by a few US-based publications suggesting that deliberate action by one of the pilots was most likely the cause of the crash.