An AvSax battery fire containment bag An AvSax battery fire containment bag

How an aircraft seat crushed a mobile phone and caused a lithium battery fire on board a British Airways passenger plane

Mobile phones crushed after being lost down aircraft seats have sparked more than 40 fires on planes in the last 5 years and continue to be a ‘significant hazard’ in the future.

The statistics, collated by the UK’s aviation regulator the Civil Aviation Authority, were revealed in an official report into a fire on board a British Airways Dreamliner caused by a mobile phone being damaged by a seat.

The Air Accidents Investigation Branch report (AAIB) states: “The CAA has received 166 reports of PEDs lost in passenger seats in the last five years. A quarter of these events resulted in fire or smoke in the cabin, demonstrating that this is a significant hazard to the safety of the aircraft.”

When mobile phones or other personal electronic devices (PED) such as tablets fall down seats on aircraft they can become crushed in the reclining mechanism which is likely to damage the device’s lithium-ion battery, sending it into what’s known as thermal runaway.

This happens 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 and they are very difficult to put out which is why many airlines carry award-winning AvSax battery fire containment bags designed to deal with overheating or burning PEDs.

Although airline manufacturers are trying to improve seat design to stop these kind of lithium-ion battery crush incidents from happening it is proving to be a challenge and there are currently no seat design requirements to prevent electronic devices from becoming trapped in seats.

Airlines are aware of the problem which is why you’ll hear safety announcements before planes take off where the crew urge passengers to contact them if they lose their phone or other personal electronic device down a seat and not to adjust the seat themselves to try to find it. This safety message is recommended by the European Union Aviation Safety Agency.

The British Airways fire has highlighted this potentially dangerous issue again and has now led to a formal recommendation from the AAIB which states: “It is recommended that the Civil Aviation Authority require that passenger seats in commercial air transport aircraft are designed to minimise the chance of portable electronic devices becoming crushed in mechanisms.”

The fire on the British Airways flight happened when the Dreamliner – a plane designed to carry 296 passengers but only had 53 on board - was flying from Miami to London Heathrow on October 1, 2020. It was 40 minutes from landing when the passenger moved her seat from the bed position to an upright one before going to the toilet. 

The flight crew quickly smelled a strong odour of sulphur, heard a hissing sound and then a large plume of smoke came from the seat in what they described as a ‘tornado’. The crew also saw an orange glow in the seat area among the smoke

They pulled the seat padding back and saw a mobile phone trapped in the seat mechanism and doused the phone with several bursts from a dry powder fire extinguisher as they feared using water could cause further problems as the seat’s mechanism was electrically-powered.

The red phone was hopelessly jammed in the mechanism. The pilots decided to continue the descent into Heathrow and a cabin crew member sat next to the phone with the fire extinguisher in case it flared up again. The phone was eventually removed by the fire service when the plane landed.

The investigation revealed that when the chair was adjusted by the passenger it crushed and badly damaged the phone’s battery which caused smoke, flames and fumes.

AvSax – the world’s best-selling lithium battery fire containment bag for PEDs on aircraft - are now on more than 15,373 aircraft operated by 80 airline companies. They have been used 33 times to deal with emergencies since the start of 2017 and every time they have been deployed the aircraft has been able to complete its journey safely with no need to divert or make an emergency landing. Diversions can be very costly to the airline company and can even run into hundreds of thousands of pounds.

AvSax won the prestigious Queen’s Award for Enterprise in the UK in 2018.

To read the full AAIB report on the British Airways incident go to