Ever gazed out at your plane taking off and wondered why your plane windows always have rounded edges, unlike the hard corner in your home? There’s a simple and very good reason.
As commercial air travel took off in the mid-20th century, airline companies began to fly at higher altitudes to save money—the air density is lower up there, creating less drag for airplanes. But for passengers to survive at 30,000 feet, the cabin must be pressurized.
To make that possible, the cabin was changed to a cylindrical shape to support the internal pressure. But at first, plane builders left in the standard square windows, Pressure builds more around the corners of square windows. Three airplanes with square windows crashed in the 1950. In the 1950s, when jetliners were starting to become mainstream, the de Havilland Comet came into fashion. With a pressurized cabin, it was able to go higher and faster than other aircraft.
However, the plane had square windows and in 1953 two planes fell apart in the air, killing 56 people in total. The reason for the crashes? The windows. Where there’s a corner, there’s a weak spot. Windows, having four corners, have four potential weak spots, making them likely to crash under stress – such as air pressure.
Fortunately, designers figured out the design flaw pretty quick. Now we have nice, round windows that can withstand the pressure of cruising altitude.