What you should learn and remember from this lesson is the following:
Personal Electronic Devices (PED’S) such as laptop’s, smartphones, powerbanks, drones, cameras, etc. are equipped with re-chargeable lithium-ion batteries. These batteries can overheat (thermal runaway) and cause heavy smoke, fire, fumes and even explosions.
Batteries in tablets and smartphones are especially sensitive for thermal runaway when they get cracked, for example between the seats or by moving the seats.
Electrical arcs along wiring bundles are often the cause of hidden in-flight fires. The electrical arcs ignite surrounding materials such as accumulated dirt and dust, contamination from spillage, lubrication or corrosion inhibitors.
In other instances, the resetting of a tripped circuit breakers can overheat wiring, ultimately leading to failure and arcing.
Electrical motors can overheat or fail and possibly ignite surrounding materials.
In the past, smoldering cigarettes left behind in the lavatory waste bin were a frequent cause of fire. Combustibles like paper towels and tissues catched fire.
Therefore, waste bins were equipped with automatic fire extinguishers. When a pre-determined temperature has been reached, a fusible plug will melt and allows the extinguishing agent to discharge in the lavatory waste bin.
Oven fires are a common occurrence on board of aircraft. Many oven fires are preventable. Some of the contributing factors to oven fires have been items left behind in the oven such as paper, towels, cloth, etc.
This video shows the thermal runaway of the lithium-ion batteries in a laptop computer. It clearly demonstrates the intensity of the fire and the health risks for passengers and cabin crew.