An airline company has been fined millions of pounds for carrying lithium-ion batteries on one of its planes.

South Korea budget airline Jeju Air was fined 9 billion won (more than £6m) for violating aviation safety laws by flying with lithium battery-powered watches on board without state authorisation.

According to Pulse business news in Korea, Jeju Air will appeal, claiming the fine is excessive for transporting Li-ion content batteries. 

The reason for the huge fire is a fear that lithium-ion batteries can spark fires and when they do they burn with such intensity and high temperatures that they could cause the plane to crash.

It is feared that lithium-ion battery fires may have caused three cargo planes to crash in the past.

Concerns about lithium batteries typically focus on large-scale shipments on board cargo planes. Battery shipments were implicated - but not proven as the cause - in crashes  near South Korea in 2011, a flight in the United Arab Emirates in 2010 and a flight in Philadelphia in 2006.

Federal Aviation Administration testing in the USA later found that halon gas used to suppress fires on planes doesn't work well on batteries in a chemical reaction called thermal-runaway. This is a rapid, uncontrolled chemical reaction within the battery that causes the internal temperature to rise. When one cell in a battery overheats it can produce enough heat - up to 900°C (1652°F) - to cause adjacent cells to overheat. This can cause a lithium battery fire to flare repeatedly.

A 2015 FAA report found that "the uncontrollability of lithium battery fires can ultimately negate the capability of current aircraft cargo fire suppression systems and can lead to a catastrophic failure of the airframe."

Jeju Air received an administrative penalty notice from the Ministry of Land, Transport and Maritime Affairs in South Korea for shipping watches equipped with lithium-ion batteries without state clearance. 

Lithium-ion batteries have been designated dangerous goods by the International Civil Aviation Organisation. 

According to the Federal Aviation Administration in the USA, between March 20, 1991 and May 2, 2018, there were 206 thermal runaway incidents involving lithium batteries either at airports or on board aircraft. 

For more on the Jeju Air story go to

* More than 50 airline companies worldwide – including some of the biggest – now carry AvSax fire mitigation bags on board. These were used 27 times in 2017.

The AvSax cools the batteries in the device, reducing the likelihood of the battery igniting but if it does go into thermal runaway it is all contained within the bag, even if the battery explodes.