HOW CAN A CORNER CAUSE A PLANE TO CRASH?
Doors, windows, fuel cap: anything subject to in-flight stresses is curved in shape to counter the effects of pressure. At an altitude of 10,000 metres the air pressure outside the aircraft is lower than the pressure inside the passenger cabin. With these differing pressures exerted on the plane, the circumference of the cabin expands by a few millimetres, like a hot air balloon when it is in the sky. If the windows were square, dangerous levels of stress could build up on their corners and lead to cracking. Basically, where there’s a corner, there’s a weak spot, which is why aerospace engineers pay particular attention to even the smallest parts on the fuselage. Meanwhile, passengers are protected from outside temperatures of minus 50ºc by a special insulation layer visible in the picture on the left.