A single power bank — the kind you may have with you right now — was all it took to cause catastrophic damage to an Air Busan plane in South Korea.
A passenger’s power bank that was in the overhead bin was compressed and went into thermal runaway, a self-heating state that can result in fire or even explosion. Fortunately for the 169 passengers and seven crew members on board, the plane was still awaiting takeoff when the flames tore through the aircraft and everyone was able to escape. The plane was a total loss.
The incident earned the attention and scrutiny of the aviation community and international media. As the news turned to coverage of the steps airlines in Asia are taking to help prevent another incident such as the one on Air Busan, a clear trend emerged: all the enforcement action was aimed at power banks. While no airlines have banned passengers from bringing power banks, aside from batteries greater than 100-160 watt-hours, most have cracked down on what is allowed during flight.
The reaction of airlines is understandable, and action is appreciated. But the narrow lens of power banks misses the root of the problem. It was the bank’s power source — a lithium-ion battery — that was the cause of the fire. Lithium-ion batteries power most of the rechargeable products we routinely carry on airplanes, from our mobile phones and tablets to our laptops and headphones. If damaged or malfunctioning, these batteries run the risk of entering thermal runaway, an uncontrollable, self-heating state that can lead to smoke, fire, toxic off-gassing, or even explosion.
A recent UL Standards & Engagement survey of airline travelers found that the average passenger brings four rechargeable devices on board each flight. Through its Thermal Runaway Incident Program (TRIP), ULSE works with the airline industry to collect data on thermal incidents in aviation to better understand the problem and identify solutions. TRIP data shows that e-cigarettes are the leading cause in thermal runaway incidents on aircraft, responsible for 35% of all incidents in 2023, followed by power banks, smartphones, and laptops.
Safer skies aren’t simply a matter of adding restrictions. Lithium-ion battery-powered products are essential to the travel experience. Further, if passengers are restricted from bringing devices with them in the cabin, they could make the mistake of packing them in checked baggage — the last place they should be because crew will be unable to retrieve the device if it enters thermal runaway.
Keeping all rechargeable devices within arm’s reach can sharply reduce the consequences of an incident. Devices powered by lithium-ion batteries are generally safest in the hands of the owner, in the cabin of the aircraft where the device can be observed for signs of thermal runaway such as heat and smoke. If these signs are noticed early, airline crews have procedures to contain the device and prevent further damage to the aircraft or injury to passengers.
To manage a fire in the event of an emergency, many airlines have brought battery fire containment products on board and prioritized training cabin crew. These fire containment products are not required on all aircraft, but we strongly encourage all airlines to have the devices, certified to UL 5800, and implement cabin crew training.
It’s alarming to think that a device so small could pose such a significant threat. But with passenger education, certified safety equipment, and cabin crew training, incidents like the one on Air Busan will become a thing of the past.
David Wroth is the Senior Director of Technology & Systems for UL Standards & Engagement, and he is also the Director of ULSE’s Thermal Runaway Incident Program — a secure, voluntary system for passenger and cargo carriers to voluntarily report and track incidents, and share insights to solve for risk. Learn more.