What is cabin pressure? Why your ears pop
At cruising altitude the outside air is very thin. The cabin is kept at a pressure where you can breathe comfortably the whole time.
How is the cabin pressurised?
Air taken from the engines or separate compressors is cooled and fed into the cabin, while a valve at the back controls how much air leaves. The cabin is kept at roughly the pressure of a mountain town 1,800–2,400 metres above sea level. Cabin air is completely refreshed every few minutes.
Why do ears pop?
In the climb and especially in the descent, cabin pressure changes slowly. When the pressure in your middle ear can't keep up, it feels blocked. It's entirely normal and usually clears on its own.
To clear your ears
- Swallow, yawn or chew gum.
- Drink water when the descent begins.
- Pinch your nose, close your mouth and blow gently.
- For babies, feeding during descent helps.
- If you have a bad cold, ask a pharmacist or doctor before flying.
Dry air
Cabin air is low in humidity. Drinking water, lip balm and eye drops make long flights more comfortable; cutting down on coffee and alcohol helps too.
