It is more due to the comprehensiveness of the investigative process.
The objective of our investigations is not to establish administrative measures or to impose disciplinary measures, but rather to determine the cause of the accident and to figure out what needs to be done to avoid similar cases going forward.
Often, we carry out in-depth analyses and visit laboratories. For instance, if an engine was the cause of an accident, we would carry out in-depth examinations and question the company who built the engine. That takes a lot of time, and it explains the fact that an investigation can take one, two of even three years.
However, allow me to reassure you. When our investigations reveal causes that, if addressed, would help prevent another accident, we do not wait for the end of the investigation and the publishing of the report to take action. Our main objective is to prevent accidents. That sometimes lengthy time frame does not prevent us from protecting our resources and people.