The fire which caused a Virgin Atlantic passenger plane to make an emergency landing is the latest in a spate of incidents sparked by lithium batteries.
Early reports from the police indicate that a mobile power bank sparked the fire in a seat on the flight from New York to London.
The crew managed to put the fire out quickly and the pilot diverted to Boston's Logan International Airport where all 217 passengers were safely evacuated from the plane.
According to BBC News, specialist bomb disposal officers inspected the aircraft after it landed and found a device between the cushions of the seat where the blaze started.
A police spokesman said: "Preliminary investigation suggests it is a battery pack consistent in appearance with an external phone charger."
Battery packs are powered by lithium ion batteries which can catch fire if they become faulty and go into a process called thermal runaway … and these kind of incidents are happening more and more on aircraft. This is why cabin crew now often include in the safety briefing a warning that if passengers lose their mobile phones down seats they should alert the staff and not try to retrieve it themselves. If they do, the phone could get crushed in the seat mechanism, sparking a thermal runaway fire.
During thermal runaway, one cell overheating in a battery 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. Incidents of thermal runaway are on the rise.
One way to tackle such incidents is to use an AvSax fire containment bag which can deal with fires in personal electronic devices. More than 15,373 are now on aircraft operated by 75 airline companies across the world – including some of the biggest and best-known.
AvSax managing director Richard Bailey said: “AvSax is the result of many years of development, drawing on experience from the production of a similar device designed for military applications such as suppressing explosions.
“Carrying an AvSax is a ‘one-size-fits-all', easy-to-use method of dealing with an incident involving a portable electronic device that has caught or is showing signs of catching fire in the cabin or on the flight deck.
“With so many poor quality and fake batteries around there’s no doubt that incidents will continue to happen.”
In January 2017 a passenger on a flight from Fukuoka in Japan to Honolulu dropped his iPhone 7 and when he tried to shift his seat it crushed the phone and battery. His fingers were singed and there was smoke and the smell of burning plastic in the cabin. The crew retrieved the phone and put it in an AvSax fire containment bag to prevent any further danger. The plane was then able to land safely.
Since then AvSax – which won the Queen’s Award for Enterprise in 2018 - have been deployed a further 30 times on planes. Deployment is so effective that extremely expensive diversions to alternate airports are usually avoided.