Why do we need a porthole?

Take-off of the aircraft leads to significant stresses on the aircraft systems and the ship's hull. Therefore, it is important for the maintenance personnel to monitor not only what is happening inside the vehicle, but also from the outside. Partly contributes to this porthole plane, through which you can fix the occurrence of a non-regular situation, for example, engine ignition or damage to the skin.

Can the porthole break when boarding?

As a rule, the airplane window is a construction formed of a three-layer glass unit. Such a system is able to withstand significant pressure drops.

Takeoff of the aircraft and the last set of heights leads to the fact that the glass is loaded to 4 tons. And if the porthole is able to withstand such pressure, it does not threaten anything when landing.

As for the inner glass, which can be touched by passengers, it is only decorative. Its damage will not affect the safety when in the cabin of the aircraft.

Why on the windows are installed curtains

Window shutters are required for several reasons:

1. After landing, the passengers' eyes must adapt to the existing lighting on board the aircraft. Only after this, the curtains move apart, allowing you to see what is happening overboard.
2. By sliding the curtains, the crew can concentrate on servicing passengers. If necessary, these curtains can be moved away if it is necessary to inform the pilots about the occurrence of emergency situations overboard, for example, to confirm the presence of an accident.
3. Curtains protect passengers from potential injuries, which can occur, for example, in a hard landing, as a result of damage to the windows of the windows.
4. The closed curtains allow to keep calm to passengers who experience fear of heights.

Why do the portholes have a streamlined shape

Such a design is not an artistic idea for making the salon interior attractive. As practice shows, a rounded, streamlined porthole better tolerates increased pressure, due to its optimal distribution throughout the surface.

This is confirmed by testing portholes of various shapes on jet engines. So, in the 50s of the last century the aircraft company De Havilland released a passenger liner that contained square portholes. However, the innovative plane was expecting a sad fate. In 1954, in the course of the flight, the square portholes did not withstand the load, and the compartment was depressurized. After the accident, the designers no longer resorted to installing inspection windows of a similar shape.

Why the hole in the window

Many passengers could notice the presence of a small hole in the window window. This hole is required to stabilize the pressure between the individual glasses of the structure. If on take-off, the ambient temperature averages 25 ° C, then when the optimum flight altitude is set to 10,000 meters, the figure reaches -35 ° C and below. As a result, the aircraft's window is subjected to significant loads due to the expansion and contraction of air.

Through the aforementioned aperture, air exits when the temperature of the surrounding space rises and enters when the indicator falls. Without the realization of such a design idea, the material for manufacturing portholes could crack and deform.

The hole in the window performs one more function. Its presence prevents the fogging of the glass and, as a result, their icing.

It should be noted that the AN-24 passenger liners of the Soviet model did not contain the holes described. An alternative to them served as tubular air outlets, which were located in the fuselage of the aircraft. This solution helped maintain a stable level of pressure between the elements of the porthole design.

What functions do individual panels of portholes perform

In the course of climbing a passenger liner, the pressure inside the cabin remains the same, and outside the aircraft, its significant drop occurs. This leads to an increased load on the portholes, which consist of several fiberglass panels.

The least durable is the inner glass, with which the passenger can contact. It serves only to isolate the noise produced by the engines of the liner, as well as to delay heat in the cabin.

The outer panel of the porthole is much stronger. This element is made of the most durable material and is capable of withstanding significant atmospheric pressure.

As for the middle panel, it plays mainly the role of insurance. This glass is used in case of damage to the outer element of the double-glazed windows. However, the probability of occurrence of such situations is extremely small.