Why are airplane windows so small?

Answer 1

High altitude aircraft need to pressurize their cabins (pack more air in) in order to offset the decreased air density (and consequently the decreased amount of oxygen in the air) at the higher altitudes so passengers and crew can continue to breathe without the need for supplimental oxygen. The way they do this is by compressing the outside air and forcing it into the aircraft cabin thereby increasing air density and oxygen concentration. The increased pressure of this compressed air can create a force against the inside of the aircraft cabin, and windows, of up to around 8 pounds per square inch (though some newer airplane designs, such as the Boeing 787, use a slightly higher level of pressurization). The greater the surface area of a window, the greater the force of the cabin air pressure pushing against it and, consequently, the greater the likelihood of breaking out a window. By decreasing the surface area of the window, aircraft designers decrease the possibility of rupturing a window and losing cabin pressure. Hope that helps. The size and shape of the windows can weaken the fuselage structure. The first British jet airliner, the de Havilland Comet, began to experience sudden crashes from high altitude. After many tests, the engineers discovered that the large windown with square corners could cause a fatigue crack to develope in the sharp corner of the window. Fatigue was an unknown science at that time. They redesigned the windows to make the smaller with large round corners and the aircraft didn't have any more dramatic crashes.

Answer 2

Becayse some people get squeamish of the height.

NO! Look up the sad history of the BOAC Comet, back in the 1950's. The large windows -- plus construction flaws -- caused three mysterious crashes, before the plane was finally grounded for good.

I have no authority or insight into this subject except for a recent newspaper article I read. That said, the article, which appeared in the Seattle Times (which has a good searchable data base), explained that the the new 787 Dreamliner will have significantly larger windows than current passenger liners. This is because the carbon fiber fueselage of the Dreamliner is so much stronger than the more commonly used aluminum, which apparently requires that the windows remain small in order to maintain the structural integrety of the aircraft.

Answer

Actually the reason for the Comet crashes was that the windows were square. The corner of the window induced a high stress concentration that resulted in fatigue cracks. It really had nothing to do with size.

The largest window that I have seen on an aircraft that I have flown on is the DC10 cockpit window. The DC10 has a front windscreen and aft of this are the primary window for the flight crew that opens. The one that I refer to is behind this and is the most aft window in the cockpit. The window is large enough that it extends from the elbow of the rear jumpseater to the top of his head.

I'm not sure why they are so small either. Or--- Why are the so low? Tall passengers have to bend down to look straight out.

Answer 3

Many modern aircraft have to be 'pressurised'. -That is the air pressure in the cabin is increased due to the heights they fly. Smaller windows are safer at these pressures.