Most People Will Go Their Entire Lives Without Ever Knowing Why Airplane Windows Are Round

The Square Window Problem
As the Comet’s fuselage was pressurized again and again, tiny cracks began forming at the corners of the square windows. These cracks were invisible to the naked eye at first, but with each flight cycle, they grew.

Eventually, the cracks reached a critical size.

At that point, the fuselage failed explosively.

The corners of the windows acted like stress amplifiers, focusing pressure into precise locations until the metal could no longer hold.

The lesson was brutal but clear:

Sharp corners and pressurized aircraft do not mix.

Why Round Windows Change Everything
Round and oval shapes don’t have corners. Without corners, there are no single points where stress can concentrate excessively.

Instead, pressure is distributed evenly along the curve.