An AirAsia Airbus A320 had to be diverted to Ho Chi Minh City on Christmas Day. This happened after a passenger’s mobile phone battery caught fire burning 20% of his body.

The incident reported by The Aviation Herald details how AirAsia flight number AK-130 operating an Airbus A320-299N registration number 9M-AGL was en-route from Kuala Lumpur International Airport (KUL) to Hong Kong International Airport (HKG) when a passenger's mobile phone caught fire.

While cruising at an altitude of 35,000 feet around 200 nautical miles south of Ho Chi Minh City, a passenger's back up battery for his mobile phone suffered a rapid thermal runaway. The resulting fire burned his left buttocks, left leg, left thigh and left arm. This gave burns to 20% of his body’s skin area.

Alert cabin crew put out the fire and offered first aid

Alert cabin crew managed to extinguish the fire and contain the faulty battery in a safe container. Thereafter, they provided first aid to the passenger’s burns.

The aircraft immediately diverted to Tan Son Nhat International Airport (SGN) where it landed safely some 35 minutes after the fire.

airasia flight attendents
Flight attendants quickly put out the fire and offered first aid. Photo: AirAsia

The passenger was straightaway transported to a local hospital where he was treated. He was then released a day later.

A replacement AirAsia Airbus A320-200N was dispatched to Vietnam the following day with a delay of 17 hours to the flight. The aircraft on which the fire occurred re-entered service some 20.5 hours later.

Why do mobile phone batteries catch fire?

While extremely rare, every once and a while the batteries in mobile telephones can catch fire. The cause of this is known as a thermal runaway.

Lithium-ion batteries are comprised of a number of Li-ion cells that have a critical temperature kind of like a boiling point. Once that boiling point is reached it enters into a cycle called an exothermic breakdown.

This then starts a process called a thermal runaway that begins to heat up other cells in the battery which then hit their critical maximum temperature. Depending on the speed of the process the battery could quietly fizzle out, catch fire or in some cases even explode.

Most mobile telephones will automatically shut down if they get too hot and most Lithium-ion batteries have built-in safety features to prevent them from catching fire. With this in mind, all bets are off should you puncture or bend the battery.

Lithium-ion batteries contain a thin layer of oxygen and a thin sheet of lithium separated by electrolyte solution that when compromised can initiate an exothermic breakdown and thermal runaway.

Most of the stories we read about mobile phones catching fire are due to faults during the manufacturing process.

Most phone fires are due to bad manufacturing

While allowing your phone to overheat in a car on a hot day or overcharging is never a good idea they rarely ever cause mobile phone fires and in most cases, a battery will stop working long before it has a chance to ignite.

If, however, the phone or battery is manufactured wrong, there is nothing you can do to prevent incidents like the one on AirAsia flight number AK-130.

airasia A320
Lithium is great for conducting electricity but can be unstable. Photo: AirAsia

Lithium is a highly unstable metal that is great for conducting and storing electricity. However, it can be dangerous when it gets mixed with other metals.

Li-ion batteries also contain graphite, cobalt, and nickel that during the manufacturing process can form deposits on the manufacturing equipment. This can contaminate the interior of the battery causing a chemical reaction.

There are millions of telephones that are made every year. The chances of one ever catching fire or exploding are very slim. As for the man’s telephone on the AirAsia flight, we will let you know what may have caused it to catch fire once we know more about the incident.