On the night of the 28th, various speculations are swirling regarding the cause of the AIR BUSAN aircraft fire incident that occurred at Gimhae International Airport. Based on passenger statements that a fire broke out inside the overhead compartment, portable electronic devices such as auxiliary batteries are being pointed out as potential causes, while the possibility of electrical short circuits has also been raised.

On the 30th, authorities including the Ministry of Land, Infrastructure and Transport's Aircraft and Railway Accident Investigation Committee are inspecting the AIR BUSAN aircraft involved in a fire incident that occurred on the 28th at Gimhae International Airport in Gangseo-gu, Busan. /Courtesy of News1

The Ministry of Land, Infrastructure and Transport stated on the 30th that it would investigate all possibilities related to the cause of the AIR BUSAN passenger aircraft fire. The previous day, the ministry announced that no suspicious items related to terrorism were found during a joint counter-terrorism investigation conducted from 12:30 a.m. to 11:30 a.m. on the 29th. It also confirmed that the wings and engine of the incident aircraft were undamaged.

The AIR BUSAN flight BX391, bound for Hong Kong, encountered a fire incident around 10:15 p.m. on the 28th while preparing for takeoff from Gimhae Airport. The flight, originally scheduled for departure at 9:55 p.m., was delayed. Some passengers reported that a cracking sound was heard from the overhead compartment where carry-on luggage was stored, followed by smoke and then fire. Photos released by YTN show red flames erupting from inside the overhead compartment cover.

The AIR BUSAN side stated in a statement released on the 29th that "a fire occurred in the rear area of the aircraft after all guests had boarded, prior to departure." According to the first observing crew member, the fire was witnessed coming from the left rear overhead compartment, according to AIR BUSAN's explanation.

It has yet to be confirmed what object inside the cargo hold initiated the fire. Some have pointed to an auxiliary battery as the ignition source. According to the Ministry of Land, Infrastructure and Transport, there were six incidents of auxiliary battery fires on national carriers in 2023. A ministry official noted, "While auxiliary batteries are frequently mentioned, it may seem plausible, but it is a premature assumption."

On the night of the 28th, the fire department is extinguishing the fire on the AIR BUSAN aircraft at Gimhae International Airport in Busan. /Courtesy of News1

The AIR BUSAN side is reportedly leaning toward the possibility that the fire originated from carry-on items and is reviewing relevant regulations. Currently, AIR BUSAN allows the carry-on of auxiliary batteries for personal use if the lithium content of lithium metal batteries is less than 2 grams or the capacity of lithium-ion batteries is under 100 watt-hours.

The possibility of a fire due to electrical short circuits inside the aircraft is also being discussed. A current pilot posted on social media, "It does not seem that the fire started in the Auxiliary Power Unit (APU); rather, it is narrowed down to a fire originating from carry-on items such as auxiliary batteries or e-cigarettes in the overhead compartment, or from smoking in the restroom, or electrical short circuits in the cabin." If electrical short circuits were the cause, it could indicate an aircraft defect or maintenance issue.

On the 30th, investigative authorities, including the Ministry of Land, Infrastructure and Transport, conducted a preliminary meeting and field investigation to confirm whether the incident aircraft was in a condition suitable for forensic examination. The incident aircraft, an Airbus A321-200, had its upper fuselage burned, exposing the interior. The wings are loaded with approximately 35,900 pounds of aviation fuel, which raises additional fire risks during the forensic process.