The Aviation and Railway Accident Investigation Board says it has retrieved data from the cockpit voice recorder or CVR from Jeju Air flight 2216 and is preparing a transcript as it looks into the crash that killed 179 people on Sunday. 

The board said during a briefing at Muan International Airport on Friday that the investigation consists of 12 stages, in accordance with South Korean law and international standards.

It said the probe is in its fourth stage, consisting of on-site investigations to gather information and materials.

It added that it has completed interviews with air traffic controllers.

The board said other steps in the investigation include analysis of the aircraft wreckage, data analysis and testing, drafting of the report, public hearings, gathering opinions from relevant countries, and holding committee reviews.