It’s a sight that air passengers hope they’ll never have to see from their window seat – the evacuation slide.
But luckily British Airways has released a clip demystifying how the safety technology works in a bid to reassure nervous flyers.
In the minute-long video, aircraft engineer Peter Dyer explains that every one of the airline’s planes has at least one of the evacuation slides.
However most of BA’s jets have far more than that, with the Boeing 777-200s stationed at Gatwick Airport equipped with eight each – one for every exit.
The evacuation slide takes just seconds to inflate after the door is opened in an emergency
In the event of an emergency they can be inflated in just six seconds and are powered by a nitrogen bottle hidden away in the body of the aircraft.
If there is a water landing many of the slides can also be detached from the fuselage and used as rafts.
Peter explains: ‘When the cabin crew activate the door they’ll put the door to automatic – they’ll move the main handle 180 degrees.
‘At that point the emergency power assist system will take over – it will fire the squib, the nitrogen pressure in the bottle will power open the door and then the slide pack will fall off and the slide will inflate within six seconds.’
The rapid inflation is powered by a nitrogen bottle hidden away in the body of the aircraft
If that doesn’t work then the cabin crew can pull an emergency handle on a velcro tab as a ‘last-ditch defence’ at deploying the gas in the slide bottle.
However, engineers check the equipment ‘on an almost daily basis’ to make sure there is enough pressure in the tanks to deploy the inflatable at speed.
If you’re wondering what the famous ‘doors to manual, crosscheck’ announcement on board means, Peter explains that too.
When the exits are set to manual, the slides are not ‘armed’ so they will not inflate if the doors are opened – for example when the aircraft is parked y at the airport.
Engineers check the equipment ‘on an almost daily basis’ to make sure there is enough pressure in the tanks to deploy the inflatable at speed
Crosscheck is a safety procedure to avoid mistakes – with cabin crew members double checking that their colleagues have indeed put the doors in the right position.
Some of the slides are also angled away from the aircraft – for example on the Boeing 777 where the exits are close to the engines.
The British Airways clip has been viewed by tens of thousands of fascinated flyers on YouTube.