A Look at Aircraft Windows
If you’ve been on an airplane and were lucky enough to get a window seat, you have probably looked at the window and asked yourself a few questions about it. For example, you may have wondered how aircraft windows work, what they are made of, and what that small hole at the window’s base is. In this blog, we will answer all three of those questions.
How Do Aircraft Windows Work?
The first thing to know about aircraft windows is that each window has several layers, each of which has its own role in protecting the aircraft. Essentially, each aircraft window is like two windows in one. There is the cabin window with which the passenger can interact, and the flight deck window beyond this one. Unsurprisingly, the flight deck window is far stronger and has more layers and parts. There are two inner layers, each in place to reinforce the window. Throughout an aircraft you will find that each part has a backup and sometimes even a second backup, and the windows are no different.
Beyond these reinforcement layers, the flight deck window also has an anti-fog system. When flying at high altitudes or in wet conditions, fog can become a problem. However, thanks to these anti-fog layers, the aircraft windows themselves will at least remain clear. On the pilot’s windshield windows, in addition to the anti-fog layer, there is an anti-ice layer. Accumulation of ice can make aircraft heavier and hurt its flight capabilities. Therefore, the anti-ice layer is essential.
What Are Aircraft Windows Made of?
Aircraft windows are not made from standard glass. Glass simply does not have the required structural integrity or resistance to pressure for it to be used at such high flight altitudes. At the high pressures aircraft windows are exposed to, glass would almost instantly shatter. Instead, aircraft windows are made from special polymers and plastics known as stretched acrylic. It is an incredibly durable material, making it a great choice for this application. This material and structural choices matter because they reinforce the window’s structural integrity during flight. By using a series of interlocking windows made from robust materials, the chances of the window cracking or shattering are markedly reduced.
What’s at the Base?
When looking over an aircraft window, one of the first things you will notice is the small hole at its bottom. This hole is nothing to worry about and, in fact, is an important design feature. During takeoff, aircraft experience a huge sum of pressure. This pressure continues when the aircraft is in the air. On top of this exterior pressure, there is also a great deal of pressure within the cabin to make it more hospitable. This is where the small hole is important - it allows for the air pressure onboard to remain constant. This small hole is informally called the bleed hole and acts as a failsafe to ensure the air pressure within the cabin remains constant. It allows air to pass through the window’s layers to keep the window pane structurally sound.