Smoke began rising from a bag a passenger had stowed under a seat on flight RS511 at around 9 p.m. local time and soon turned into a fire, according to Air Seoul. The bag held a power bank kept in a pouch, Korea JoongAng Daily reported.

Crew members put out the flames using bottled water and other means before firefighters arrived to check on passengers, The Chosun Ilbo reported. Some passengers complained of breathing discomfort, but none needed hospital treatment and no injuries were reported.

The aircraft had 228 people on board, including seven crew members. Many of the passengers were families heading to the central Vietnamese city for Chuseok, South Korea's autumn harvest holiday.

An Air Seoul plane. Photo courtesy of Gabriella918

Air Seoul had everyone leave the plane and brought in another aircraft so the original could undergo safety checks. The replacement flight took off about two hours and 50 minutes late with 219 passengers, after two chose not to travel.

Air Seoul and fire authorities are still working to determine the cause. The passenger had taken measures to prevent the battery from short-circuiting, Korea JoongAng Daily reported.

Some passengers have suggested the fire started while the power bank was being used to charge an e-cigarette. Air Seoul said it presumes the power bank caught fire but is "still verifying the facts, including whether it was in use," The Chosun Ilbo reported.

Since April 20, South Korea has limited air passengers to two power banks each and banned using or recharging them on board, under rules it drafted and the International Civil Aviation Organization adopted as a global standard. Passengers must keep the batteries with them, sealed in a bag or insulated, and not in overhead bins, Korea JoongAng Daily reported.

The rules followed a January 2025 fire that destroyed an Air Busan jet at Gimhae International Airport in Busan after a power bank stored in an overhead bin ignited.