Why do plane windows have tiny holes in them?

That little hole is kind of a big deal
That little hole is kind of a big deal Credit: getty

As part of our Travel Truths series we have unravelled the many mysteries of modern aviation: like what happens when you flush a plane loo and why cabin lights are dimmed during takeoff and landing.

The latest question we’re endeavouring to answer is one that many frequent fliers will have pondered: why exactly are there tiny holes in plane windows?

Surely we shouldn’t have holes in the windows of planes? On the contrary. Those holes, which are only present in the middle pane of our triple-glazed planes, are actually there to keep us safe. Without them, passengers could be in trouble.

But before we explain how these “bleed holes” help keep us alive, it’s important to understand how air pressure...

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