Inspectors conduct a risk management assessment on the Air Busan aircraft at Gimhae International Airport in Busan, Friday. Yonhap

The government will formally launch a joint investigation with foreign experts on Monday to find the cause of the fire that destroyed Air Busan's passenger plane on Tuesday.

The Aviation and Railway Accident Investigation Board announced the decision on Friday after safety issues were cleared by inspectors in regard to investigating the aircraft still containing 35,900 lbs (16,280 kilograms) of jet fuel and other potentially hazardous materials such as oxygen tanks.

The plane, an Airbus A321, had been scheduled to fly to Hong Kong from Busan when a fire broke out in an overhead bin near its tail at around 10:15 p.m., just before its takeoff. All 176 people onboard ― 169 passengers and seven crewmembers ― escaped successfully using emergency slides.

"It has been confirmed that an investigation can be conducted safely without offloading the fuel in the aircraft," an official told reporters after a risk management assessment at Gimhae International Airport. "Each team of six to seven people will enter the plane at a time due to the risk associated with space issues."

Officials said they decided to put off the investigation until Monday because rain is forecast in the region over the weekend, adding it would be ideal to complete the task without pausing during the process due to the bad weather.

Officials at the investigation board under the Ministry of Land, Infrastructure and Transport, experts from police and fire authorities as well as France, where the Airbus headquarters is headquartered, plan to begin the investigation Monday morning.

The focus of the investigation will be establishing what exactly caused the flame. Witnesses said they had heard a crackling sound ― something like an electronic device burning ― before smoke, apparently originating from an overhead compartment, began to fill the cabin.

While there are multiple potential causes for that fire, such as a short circuit in the aircraft, suspicions grow that a portable battery may be the cause.

According to ministry data shared by the office of Rep. Lee Yeon-hee of the main opposition Democratic Party of Korea, there were six battery-caused fire cases occurred in planes run by Korean airlines in 2023; between January and August 2024, there were five such cases.

Just seven weeks ago, Air Busan had such an incident. A fire, triggered by a portable battery problem, prompted flight attendants to use fire extinguishers to put it out.

On Friday, suitcases were taken out of the damaged aircraft. After security checks, they will be handed over to the passengers, according to officials.

The Air Busan fire came only a month after a Jeju Air plane crashed at Muan International Airport in South Jeolla Province, which killed all but two of the 181 people onboard.