The takeoff of an aircraft leads to significant loads on the on-board systems and ship's skin. Therefore, it is important for maintenance personnel to monitor not only what is happening inside the air vehicle, but also outside. This is partly facilitated by the window of the aircraft, through which you can fix the occurrence of an emergency situation, for example, an engine fire or damage to the skin.
Can the porthole crash during landing
As a rule, an aircraft porthole is a structure formed from a three-layer double-glazed window. Such a system is able to withstand significant pressure drops.
The takeoff of the aircraft and the last climb leads to the fact that loads of up to 4 tons are placed on the glass. And if the porthole is capable of withstanding such pressure, nothing threatens it during landing.
As for the interior glass that passengers can touch, it is only decorative. Its damage will not affect the safety while in the cabin of the aircraft.
Why are curtains installed on the windows
Window shades are required for several reasons:
- After landing, passengers' eyes must adapt to the available lighting on board the aircraft. Only after that the curtains move apart, which allows you to see what is happening overboard.
- By closing the curtains, the crew gets the opportunity to concentrate on serving passengers. If necessary, these curtains can be pulled back if you need to inform pilots about the occurrence of abnormal situations overboard, for example, to confirm the presence of an accident.
- Curtains protect passengers from potential injuries that can occur, for example, during a hard landing, as a result of broken windows.
- The curtains are closed to keep passengers calm and fearful of heights.
Why airplane windows are streamlined
This design is not an artistic idea to make the interior of the salon attractive. As practice shows, the rounded, streamlined window of the aircraft better tolerates increased pressure, due to its optimal distribution over the entire surface.
The above is confirmed by the testing of portholes of various shapes on vehicles with a jet engine. So, in the 50s of the last century, the aircraft manufacturer De Havilland released a passenger liner that contained square windows. However, a sad fate awaited the innovative aircraft. In 1954, during the flight, the square windows could not withstand the load, and in the cabin there wasdepressurization. After the accident, the designers no longer resorted to installing viewing windows of a similar shape.
Why is there a hole in the porthole
Many passengers may have noticed the presence of a small hole in the porthole window. The named hole is required to stabilize the pressure between the individual panes of the structure. If during takeoff the ambient temperature averages 25°C, then when the optimum flight altitude reaches 10,000 meters, the figure reaches -35°C and lower. As a result, the aircraft window is subjected to significant stress due to the expansion and contraction of air.
Through the same hole, air exits when the ambient temperature rises and enters when the indicator falls. Without the implementation of such a design idea, the material of the portholes could crack and deform.
The hole in the porthole performs another function. Its presence prevents fogging of glasses and, as a result, their icing.
It is worth noting that the Soviet-style AN-24 passenger liners did not contain the described holes. An alternative to them was tubular air vents, which were located in the skin of the aircraft fuselage. This decision contributed to maintaining a stable level of pressure between the structural elements of the windows.
What are the functions of individual porthole panels
During the climb by the passenger liner, the pressure inside the cabin remains the same, and outsidethe aircraft undergoes its significant fall. This leads to an increase in the load on the windows, which consist of several fiberglass panels.
The least durable is the inner glass that the passenger can come into contact with. It serves only to isolate from the noise produced by the engines of the liner, as well as to retain heat in the cabin.
The outer panel of the porthole is much stronger. The specified element is made of the most durable material and is able to withstand significant atmospheric pressure.
As for the middle panel, it mainly plays the role of insurance. Such glass is used in case of damage to the outer element of the double-glazed window. However, the likelihood of such situations occurring is extremely small.
