From crash to conclusions: How AAIB investigates aircraft accidents

The initial notification of the occurrence is sent to the country of registry, the country of operator, the country of manufacturer, and the country of design of the aircraft involved. The Accredited Representatives from the countries concerned are associated with the investigation undertaken by AAIB.

Initial evidence collection and investigation

Upon receiving notification of an occurrence, AAIB immediately deputes one or more investigators to reach the site and gather evidence. MoCA officials said the aim of the initial investigation is to gather and preserve perishable evidence for subsequent analysis, which may be lost over time.

The activities may include recording and mapping any signs of impact with terrain or objects in the vicinity; recording the distribution of wreckage; photography and videography of the site and wreckage; wreckage examination; and the retrieval of Flight Recorders or any component perceived to be of value to the investigators.

It may also include interviewing witnesses and recording their statements; gathering data from onboard systems, GPS devices, CCTV, and other surveillance devices available at the site; obtaining recordings and data from ATC and radar stations; and obtaining samples from the site, MoCA officials said.

Examination and analysis

The evidence and data gathered by AAIB Investigators are subjected to detailed scrutiny to build a comprehensive understanding of the circumstances surrounding the occurrence under investigation and any safety issues that had a causal or contributory effect on it. This may require investigators to review complex and varied sets of evidence and seek clarifications from various stakeholders, as needed, officials said.

Documents and records gathered from the operator, regulator, involved personnel, or other stakeholders are studied and analysed by the investigators. The results of the analysis of Flight Recorder data, along with examinations of components or other reports from specialists, are reviewed and may require deliberation with various stakeholders.

Officials said that sometimes the examination and analysis of different sets of evidence and data may provide a vague, incomplete, and/or contradictory picture of the situation. This may prompt the collection of additional evidence or require further interviews with witnesses or other personnel.

Drafting, acceptance and dissemination of final report

After the examination and analysis of all available evidence are complete, the investigation team drafts the report, which includes all factual information, analysis, conclusions, and safety recommendations. Once the draft report is finalised, it is shared with the countries of registry, operator, manufacturer and design and comments are sought and reviewed.

The draft report is reviewed internally and submitted to the director general, AAIB, for acceptance.