The interesting reason airplane windows have a 'bleed hole' – and why you shouldn't place your head against it to get some sleep

Australians taking the sky for the first time since the Covid pandemic ended are noticing the tiny ‘hole’ on their plane windows for the first time – and have questioned what it does. 

Known as the ‘bleed hole’ the tiny opening in the window of commercial passenger planes is actually an important safety feature, according to aviation experts.

The hole helps to regulate how much pressure from the cabin is exerted onto the window’s panes and it makes sure that if the window is going to break, the outer pane goes first.

So it’s best not to touch the bleed hole or cover it in any way, so it can do its job effectively while you’re in the air. 

This information appeared to ‘blow the minds’ of eager travelers online, with a post on the holes going viral.

While hundreds of others revealed they had ‘never noticed’ the holes.

‘The way I’ve never noticed but I’m gonna look when we fly up,’ one woman said.

While others wondered what would happen if everyone ‘blocked the holes’ not realising they are in the centre pane of a three-pane system. 

The question was posed by Robbie Gonzalez from iO9 to director of technology Marlowe Moncur, from GKN Aerospace. 

A patent filed by Daimlerchrysler Aerospace Airbus in 1997 explained that this ‘air conduit’ helps maintain ‘external atmospheric pressure inside’ the panes.  

On a plane, the air is pressurised by engines that compress it as it moves through a series of fans. 

To maintain cabin pressure, even at high altitudes, this incoming air is held within the cabin using a so-called outflow valve.