Black box data tells all about deadly flight Air India 171: Full sequence of events that ended in a tragic crash

On June 12, tragedy struck as Air India Flight 171 crashed just moments after takeoff, despite no signs of mechanical issues or external threats like bird strikes. In a shocking chain of events, both engines shut down mid-air, cockpit confusion unfolded, and a desperate Mayday call went unanswered.

A detailed sequence reconstructed from technical logs, cockpit voice recordings, and CCTV footage now reveals the terrifying final moments of the flight, offering a chilling look into what caused the deadly crash.

Below is the minute-by-minute breakdown of what exactly happened from takeoff to impact.

Here is the sequence of events leading to the deadly crash on June 12:

• Flight AI423 had a Pilot Defect Report (PDR) entry for a status message: “STAB POS XDCR” in the tech log.
• Troubleshooting was carried out, and the aircraft was released for flight.
• The pilots had adequate rest, underwent pre-flight breath analyser tests, and were found fit to operate the flight.
• Fuel on board was 54,200 kg, and the takeoff weight was 213,401 kg, which was within the maximum allowed limit of 218,183 kg.
• No dangerous goods were onboard the aircraft.
• The aircraft began its takeoff roll at 08:07:37.
• The air/ground sensors transitioned to ‘air mode,’ consistent with liftoff at 08:08:39.
• The aircraft achieved a maximum recorded airspeed of 180 knots IAS at approximately 08:08:42.
• Immediately after, Engine 1 and Engine 2 fuel cutoff switches were moved from RUN to CUTOFF positions, one after another, with a one-second gap.
• As fuel supply to the engines was cut off, both N1 and N2 values began to decrease from their takeoff values.
• In the cockpit voice recording, one pilot is heard asking the other, “Why did you cut off?”
• The other pilot responded that he did not.
• CCTV footage from the airport showed the Ram Air Turbine (RAT) deploying during the initial climb, immediately after liftoff.
• No significant bird activity was observed near the flight path.
• The aircraft began to lose altitude before crossing the airport perimeter wall.
• According to EAFR data, both engines' N2 values dropped below the minimum idle speed, and the RAT hydraulic pump began supplying power at around 08:08:47.
• At approximately 08:08:52, Engine 1’s fuel cutoff switch transitioned back from CUTOFF to RUN.
• At 08:08:56, Engine 2’s fuel cutoff switch also transitioned from CUTOFF to RUN.
• When fuel control switches are moved from CUTOFF to RUN during flight, the Full Authority Dual Engine Control (FADEC) system automatically initiates a relight and thrust recovery sequence, including ignition and fuel reintroduction.
• Exhaust Gas Temperature (EGT) began rising for both engines, indicating relight.
• Engine 1’s core deceleration stopped, reversed, and began recovering.
• Engine 2 managed to relight but could not stop the core speed deceleration. It kept reintroducing fuel in attempts to increase acceleration and achieve recovery.
• The EAFR recording stopped at 08:09:11.
• At around 08:09:05 UTC, one of the pilots transmitted: “MAYDAY, MAYDAY, MAYDAY.”
• Air Traffic Control (ATCO) asked for the call sign but received no response.
• ATCO then observed the aircraft crash outside the airport boundary and immediately activated the emergency response.