"Cause of Air Busan Fire Identified as Internal Short Circuit in Auxiliary Battery" ... Interim Results Announced

Ministry of Land, Infrastructure and Transport Aviation and Railway Accident Investigation Board, Results of Detailed Analysis

The fire on the Air Busan passenger plane that occurred last January is believed to have started due to an internal short circuit in an auxiliary battery, according to preliminary investigation results.

On the 14th, the Aviation and Railway Accident Investigation Board of the Ministry of Land, Infrastructure and Transport announced that this conclusion was drawn based on a detailed analysis by the National Forensic Service. From immediately after the accident, passengers and crew members strongly suspected the auxiliary battery fire. After collecting evidence and conducting detailed analyses such as CT scans and microscopic examinations, this was tentatively concluded.

The National Forensic Service's analysis identified traces of melting caused by electric current on the remains of the auxiliary battery found inside the aircraft. Accordingly, it was concluded that the initial ignition likely occurred due to “insulation breakdown,” meaning a short circuit between the positive and negative electrodes inside the battery. However, the National Forensic Service noted that because the battery was severely damaged, it is difficult to determine the exact cause of the short circuit. They explained that the possibility of the fire starting from aircraft internal facilities other than the battery is extremely low.

On January 28, a joint investigation team is conducting a safety inspection ahead of fire analysis on the Air Busan aircraft where a fire occurred. Photo by Yonhap News.

The ignition location is estimated to be around the overhead bin above seat 30 on the left side. In videos taken by passengers at the time of the fire, flames were first seen at the overhead bin above row 30 on the left side of the aircraft interior, and the burnt remains of the auxiliary battery were also found on the floor nearby.

Earlier, on the 3rd of last month, the investigation board, the National Forensic Service, the police forensic team, and the fire department conducted a joint fire inspection of the Air Busan fire incident aircraft. Through this, they secured electrical wiring, cabin lighting fixtures, and auxiliary battery remains from the seat area between rows 28 and 32 on the left side of the cabin.

The board stated, "Based on the investigation results so far, we will continue the investigation focusing on the possibility of a fire caused by the auxiliary battery," and added, "If safety measures are needed during the accident investigation process, safety recommendations will be issued to airlines and others." They further said, "We will do our best to accurately determine the cause of the accident, and the disclosure of additional investigation status will be decided considering its impact on the ongoing investigation."