The investigation into the Air India plane crash will be conducted primarily by the Aircraft Accident Investigation Bureau (AAIB) of India, which is the designated authority for such investigations in the country. The AAIB operates under the Aircraft (Investigation of Accidents and Incidents) Rules, 2017, and is an independent body under the Ministry of Civil Aviation.

Here’s a breakdown of how the investigation is typically conducted:

1. Objective: The sole objective of the investigation is prevention of future accidents and incidents, not to apportion blame or liability. Any investigation by the AAIB is separate from judicial or administrative proceedings.
2. Multidisciplinary Team: The AAIB forms a multidisciplinary team for the investigation. This team often includes:
   • An Investigator-in-Charge.
   • Aviation medicine specialists.
   • Air Traffic Control (ATC) officers.
   • Representatives from the State of Design (e.g., the US National Transportation Safety Board – NTSB, since the aircraft was a Boeing Dreamliner) and the State of Manufacture (USA), as well as the State of Registry and State of the Operator.
3. Site Investigation and Evidence Collection:
   • Investigators immediately go to the crash site to collect and preserve perishable evidence, wreckage samples, and the crucial black boxes (Flight Data Recorder – FDR and Cockpit Voice Recorder – CVR).
   • In the case of the recent Air India crash, India successfully decoded the black boxes domestically for the first time.
   • They collect data from various sources, including the airline operator, regulatory bodies, and involved personnel.
   • Investigators also look at CCTV footage from the surrounding area and interview witnesses.
4. Black Box Analysis:
   • The FDR records hundreds of parameters about the aircraft’s performance (altitude, airspeed, engine parameters, control surface positions, etc.).
   • The CVR records cockpit conversations and other sounds within the cockpit.
   • The data from these black boxes is meticulously analyzed to reconstruct the sequence of events leading to the accident.
5. Expert Analysis: The AAIB may engage domain experts and collaborate with other agencies, such as Hindustan Aeronautics Limited and DGCA laboratories, for specialized analysis. This can include:
   • Analysis of aircraft remnants.
   • Post-mortem reports.
   • Component inspections.
   • Review of maintenance records.
   • Assessment of pilot training and health, including psychological aspects.
6. Preliminary Report: For major accidents, countries are encouraged by ICAO (International Civil Aviation Organization) to publish a preliminary report within 30 days. This report provides initial findings but does not typically reach definitive conclusions about the cause. The AAIB for this Air India crash released its preliminary report on July 12, indicating that the fuel cutoff switches had been activated shortly after takeoff.
7. Final Report: The investigation is a complex process and takes time. The final report aims to establish the root cause(s) of the accident and suggest corrective measures to prevent similar occurrences. ICAO guidance suggests a goal of releasing the final report within 12 months.
8. Safety Recommendations: Based on their findings, the AAIB issues safety recommendations to relevant bodies, such as the Directorate General of Civil Aviation (DGCA) in India or international aviation regulatory bodies, for implementation and monitoring.

It’s important to note that throughout the process, the AAIB aims for transparency and impartiality, although there can be external pressures and differing interpretations of preliminary findings, as seen with some media reports and statements from pilot associations regarding the recent Air India crash.