Amazing new software has been developed which is more likely to spot potentially deadly lithium-ion batteries being put into aircraft holds.

Passenger plane operators now insist that lithium-ion batteries and the small electronic devices that are powered by them - ranging from laptops to mobile phones - are now carried in aircraft cabins.

This is because if they overheat and catch fire they can be dealt with by cabin crew and more than 50 operators worldwide now carry AvSax fire mitigation bags on board.

A single personal electronic device that overheats and catches fire in checked luggage on an airliner can overpower the aircraft’s fire suppression system, potentially creating a fire that could rage uncontrolled.

Safety experts had thought that single lithium battery fires would be knocked down by the flame-retardant gas used in passenger airliner cargo holds. But tests conducted by the United States Federal Aviation Administration found the suppression systems can’t extinguish a battery fire that combines with other highly flammable material, such as the gas in an aerosol can or cosmetics commonly carried by passengers in their luggage. In the worst possible scenario the blaze could bring a plane down.

But how are batteries left in luggage due to go into the cargo hold spotted by the security detection staff?

Akshat Rathi from online news magazine Quartz said: “Lithium-ion batteries under pressure like in the cargo holds of commercial airplanes are capable of catching fire or, worse, exploding.

“These batteries, though small, can cause a lot of damage. For example, a battery 20 times the size of the one in a typical smartphone is capable of blowing out the windows of a mid-sized room.

“With more people using battery packs, such as those in drones, cameras, or simply power bricks to charge the many devices we own it's become vital to ensure that no lithium-ion battery gets through to a plane's cargo hold undetected.”

Akshat said that since 1991 the US Federal Aviation Agency has reported 225 incidents of smoke, fire, extreme heat or explosion involving lithium-ion batteries in cargo or baggage.

He added: “The way to catch stray lithium-ion batteries is to blast X-rays on the luggage. When exposed, the electromagnetic radiation passes through and bounces off various things inside the bag differently depending on the density of the many types of material. Detectors collect these X-rays and create an image of what's inside the bag.

“Most airports use some form of software to help aid the process but human intervention is needed and that makes the process prone to errors. To help cut down on those mistakes Smiths Detection, a multinational supplier of X-ray detectors at airports, built software they claim can drastically cut the need for human input. It uses a deep-learning algorithm to improve the rate of detection to up to 90%.

“This deep-learning algorithm takes feedback from its successes and failures and refines its method moving forward using data on the shapes, textures and materials that accurately indicate the presence of a lithium-ion battery. It's self-updating so it learns and improves on the fly. And because it's a software upgrade, the company can deploy its technology on already-existing Smiths detectors.”

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More than 50 airline companies across the world – including some of the biggest and best-known - now carry AvSax which means well over 13,000 AvSax fire mitigation bags are on board aircraft in case of any emergency sparked by fires in passengers’ electronic devices.

The bag has been used 27 times to deal with emergencies since the start of 2017.

How do AvSax work?

If an electronic device starts to seriously overheat or emit smoke the cabin crew will pour at least two litres of water into an AvSax. It is imperative to first knock down the flames from the device using an on board halon fire extinguisher, then transfer the device into AvSax before it reignites. Additional water is then required. The water activates the polymer gel inside the bag causing it to expand around the device. Should the device keep on venting then the AvSax is tough enough to absorb the energy.

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.

Amazingly, the water is absorbed into the internal lining of the bag so the device is dry when it is removed.