The Anatomy of Aircraft Windows
If you have ever sat on the window seat of a passenger flight, you may have noticed that there is a tiny hole in each window leading to the outside. As aircraft must remain at specific pressures for the safety of individuals, it may seem counterproductive to leave openings in the window structure. Despite the concerns that one may have, these tiny holes actually provide for safety, and they do not actually connect to the outside atmosphere.
When looking through an aircraft window, it is important to note that you are actually seeing through three different panes, each providing for a different function. The first pane, that is closest to the airplane cabin and the passenger, is called the scratch pane. This is the pane that ensures that the center pane is undamaged by passengers, as well as provides insulation to protect the airplane cabin from the extremely low temperatures of the outside atmosphere.
The middle windowpane is the one with the small hole, known as a bleed hole. This pane is important, as it allows for cabin pressure to be balanced with that of the gap between the outer and middle panes. The most outward pane is the thickest one, sealing the airplane cabin completely from the outside air.
As an aircraft increases its altitude during the takeoff process, the difference of pressure between the airplane cabin and outside atmosphere continuously rises. As this difference increases, a great amount of stress begins to be exerted against the airplane window parts and panes as pressure attempts to escape and equalize. To mitigate this difference, the bleed hole allows for pressure to be reduced on the middle pane, allowing the outer pane to take the brunt of the force.
This is a gradual process throughout the flight, allowing the pressure to be applied slowly to ensure safety and integrity. Through a bleed hole, equilibration between the airplane cabin and the air gap between the panes can be made. Because the hole leads from the cabin to the outer pane, the bleed hole does not allow any pressure to escape the structure of the aircraft.
Beyond equalizing pressure between the panes, the bleed hole also ensures the safety of passengers even if the outer pane is somehow damaged. Because the middle pane is also extremely robust, it would still be capable of protecting passengers from the lack of air pressure from the outside atmosphere. Even with the bleed hole, the
aircraft’s pressurization system would be able to compensate and ensure safety during the flight.
The bleed hole is also important beyond safety, as it also prevents the formation and build up of fog. The difference in
bearing temperature between the airplane cabin and the outside temperature is extreme, sometimes in amounts of up to 120 degrees. Through the bleed hole, moisture can be released from the gaps in between the airplane window parts.
When it comes time to begin sourcing the airplane window parts and other aerospace components that you need for your operations, ASAP Sourcing Solutions has you covered with everything you are searching for. ASAP Sourcing Solutions is owned and operated by ASAP Semiconductor, and we can help you find the aviation,
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As a premier supplier of parts for the aerospace, civil aviation, and defense industries, we're always available and ready to help you find all the parts and equipment you need, 24/7x365. ASAP Semiconductor is an FAA AC 00-56B accredited and ISO 9001:2015 certified enterprise. For a quick and competitive quote, email us at sales@asap-sourcingsolutions.com or call us at +1-714-705-4780.
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mark watkins
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Posted on August 19, 2019
aerospace