ASAP Sourcing Solutions Blog

When you’re in flight, the only thing separating you from the thin air outside is an airplane window. On one side, there’s a warm, pressurized cabin where you can work, watch movies, sleep — and on the other, air that is not suitable to breathe. Between the two, incredibly sturdy windows. Aircraft cabin windows and windshields are designed to withstand high pressure environments that normal windows couldn’t function in. 
 
A cabin window consists of three panes: an outer pane that is flush with the outside fuselage, an inner pane which has a pressurization hole in it, and a thinner, non-structural plastic pane called a scratch pane. Passengers can’t touch the inner pane or the outer pane for safety reasons; instead, passengers can rest their weary heads against the scratch pane. The scratch pane isn’t actually part of the window assembly itself but installed separately.
 
As your aircraft gains altitude, the pressure acting on the outside of the plane drops; the air is much less dense the higher your plane climbs. Because aircraft cabins are pressurized to about 6,000 feet for passenger comfort, there is more pressure inside the plane than acting on it from the outside. That pressure is pushing against the fuselage and the cabin windows. The little hole on the inner panel allows some of the cabin air to escape into the pocket between the inner and outer panes and equalize. This forces the outer pane to take all of the load, albeit slowly. The small hole is designed to function so that as the plane ascends the pressure slowly equalizes for aircraft engine control.
 
The inner and outer pane thickness is specific to each type of aircraft. Inner panes are generally thinner at approximately 0.2” thick and are only present as a fail-safe if the outer pane fails. The outer panes are thicker—at approximately 0.4” thick—and carry the pressure loads for the life of the window. The increased thickness is meant to allow for engagement with the airframe structure while maintaining the required strength. The air gap is approximately 0.25” and also varies for each aircraft.
 
Aircraft cabin windows are not made of glass but with a material referred to as stretched acrylic. It’s a lightweight material manufactured by a few global suppliers for the various aircraft flying today. One such supplier is UK-based GKN. The largest manufacturer of cabin windows worldwide, Hawker Beechcraft makes cabin windows for the Boeing 737 and the Boeing 787, and most other aircraft. Stretched acrylic is produced by stretching the base material of as-cast acrylic, and provides better resistance to cracks, reduced crack propagation, and improved impact resistance.
 
Another type of window that exists on aircraft is the windshield/cockpit window. It consists of a toughened glass pane, a heating/deicing element, a vinyl layer, surrounded by another layer of reinforced glass. Airliners utilize acrylic as well due to its versatility. The cockpit windows are thicker and stronger as they have to withstand bird strikes—which aren't an issue on the sides of the fuselage where the cabin windows are. Jet windows are also made of stretched acrylic but are a single layer in a far more complex curved form.

Also referred to as a “bleed” or “breather hole”, those tiny holes at the bottom of the airplane windows parts actually have a purpose. Airplane windows are thicker and stronger than they may appear, and for a good reason.
 
In order to keep airplane cabins windows relatively comfortable, a pressurized atmosphere allows for proper breathing and comfortable temperature. What makes this possible while still being able to watch the skies around you is a three-layered window, made to equalize the low pressure outside and the high pressure inside.
 
Each layer of the window has a specific function to make the system work. The outside window, on the exterior of the plane, is 12mm thick. It serves as a protective layer to keep the outside air out, being the most structurally sound layer. The middle layer is 6mm thick and contains the bleed hole. This hole ensures balance between the high-pressure cabin and low-pressure atmosphere outside. The innermost layer, on the interior of the plane, is 4mm thick, and acts as the insulated barrier. Also known as the scratch pane, is a protective layer to prevent the passengers from feeling the cold temperature outside while the plane is at cruising altitudes.
 
Now the little bleed hole that some people may never notice has an important function. As we already mentioned, it helps neutralize the pressure inside the cabin to make it comfortable for customers, but it also helps release moisture. This helps prevent fog and frost from building up on the inside of the window. If you have ever noticed that frost may build up slightly in a round pattern, it is the combination of window surface temperature, cabin humidity, and rate of air flowing through the hole.
 
If there was no bleed hole, there would be unequal pressure in the cabin and outside the aircraft. This can lead to the windowpanes breaking. With the ever-growing technology, airplane windows may not need this bleed hole. The newest plane that does not have this tiny hole is the Boeing Aircraft 787.

The Federal Aviation Administration requires that all aircraft have ice built up on their wings and fuselages stripped off before takeoff. This is because ice, if not removed from the aircraft’s engine control surfaces, can negatively affect the handling characteristics of the aircraft and pose a safety hazard.
 
The best method for deicing an aircraft is simply to heat it up. Heated hangars can be kept at a temperature that melts ice, whereupon it can be wiped away with a towel. Afterwards, a thin coating of freezing point depressant (fluid) is applied to the aircraft’s wings to prevent ice from forming again during takeoff and flight. However, this space is often at a premium, and some smaller airports may not have any heated hangars available at all.
 
Another option for preventing ice buildup is using aircraft covers designed to shield the wings and other components vulnerable to ice build-up. These covers also have the advantage of being easy to store, and relatively inexpensive. However, icing can still occur between taking the covers off and take-off, so applying FPD liquid may still be necessary.
 
The final and most common method for deicing aircraft is using spray equipment that applies FPD liquids to the plane. Most airports provide portable spray equipment like pressurized containers and spray wands to apply de-icing liquid, which consists of ethylene glycol and propylene glycol. As the FPD melts ice however, it mixes with the water and dilutes. If the aircraft is on the ground for extended periods of time and waiting for takeoff, it may be necessary to apply additional coatings of FPD. Glycol is also toxic, much like the antifreeze in automobiles and refrigeration equipment, so safety precautions must be taken to prevent exposure.

We know that an aircraft bearing component is quite important in aviation, but let’s take a look at another industry— wind energy. Wind turbine technology is on the rise as more U.S. companies look to invest in renewable energy. Bearings are an important component used in wind turbine operation, and they are often utilized in the main shaft. There are two integral bearing variations that you will come across within the main shaft of a wind turbine— spherical roller bearings and tapered roller bearings.
 
Spherical roller bearings (SRB) are usually used in single SRB designs, where a 3-point mount system is supported by one main bearing. Because the main bearing can take some of the load, two torque arms are designated to carry gearbox reaction stressors and loads. Failures of this mechanism occur because of two occurrences—application of too much thrust, or inadequate lubricant generation. Regular maintenance concerning the former issues is extremely important, as full replacement of a main shaft and its bearings can cost upwards of $450,000.
 
Tape bearings (TRBs) are designed to improve the powertrain performance of the turbine. They are engineered to provide increased stability to the main shaft through a load sharing construction of rows, and predicted roller-to-race interactions. There are three main types of TRBs, including: widespread single TRBs, large diameter TRBs, and single preloaded TRBs.
           
A widespread single TRB is considered economic in design because of its compact size and its ability to preload a whole turbine system using just two TRBs. The system can adjust bearing capacity through an upwind and downwind series. These components act like bookends to the widespread center between the two bearings. The series manages applied load by adjusting the contact angle when necessary.
 
A large diameter TRB, sometimes referred to as a TNA bearing, is most often seen on direct-drive wind turbines. It is known for its easy set up and has excellent ratings for field performance. This component utilizes a spacer unit that is placed between two cone races at a steep angle. The angle of the cones creates what is called high tilting stiffness within a compact axial design, allowing the turbine manufacturers to reduce overall nacelle length if necessary.
 
A single preloaded TRB can manage higher radial loads and thrust loads than an SRB. It utilizes two bearing rows in order to evenly distribute load sharing. Because of its design, this mechanism is able to accommodate higher load capacities and has the capacity to tolerate greater system misalignment.

Jet engine technology has revolutionized global air travel since 1949. The British Overseas Aircraft Corporation (BOAC) introduced the world’s first commercial jet airliner, the Comet 1, which took its maiden flight on July 27th, 1949. It was followed by the iconic development of Pan American Airlines, whose transatlantic routes sparked the beginnings of the competitive aerospace market we know today. In celebration of the jet engine’s evolution, let’s take a look at five fun facts about modern commercial aircraft engines and also look at the how Aircraft engine control.
 
What is the most widely used commercial engine?
Turbofan engines are the most common propulsion system utilized for commercial aircraft. This type of engine has 4 integral parts: turbofan, compressor, combustion chamber, and turbines. They also contain Aircraft Engine Valvetrain parts.
 
What is the most powerful commercial jet engine?
The General Electric 90-115 B, which is utilized by Boeing’s 777- 300 ER, holds the Guinness World Record for a most powerful commercial jet engine. It generates an astounding 115,000 pounds of thrust.
 
How many hours per day is an aircraft engine in operation?
The average commercial aircraft will spend 16 hours a day in the air. Flight cycles per aircraft vary, but the average flight cycle length is 1.9 flight cycles per day. A flight cycle is a series of stages an aircraft experiences from take-off to landing. Bonus fun fact—we use the term “flight cycle” for birds of flight as well. The term describes the process of flight from the moment they expand their wings to the moment they land.
 
How much does one aircraft engine cost?
Price per engine varies depending on the market, size of the engine, and thrust provided. Usually, the price of the engine/s is integrated into the total cost of an aircraft. A few popular engine models are the Pratt and Whitney 4056, Rolls-Royce RB211, and General Electric CF6. The aircraft these engines are seen in, and their average price, are listed here in consecutive order: Boeing 747- 400, $5.8 million; Boeing 757, $10 million; and Airbus A330, $11 million.
 
What is the hottest temperature within an engine?
Any given aircraft engine can reach temperatures of 1400 ? or 2552 ?. This temperature occurs in the combustor, where fuel and compressed air 
are mixed.

 
“Winter is coming”, Game of Thrones infamous motto from House Stark is used to instill the characters and audience with a sense of dread for the oncoming winter and the threats that come with it. Well, it instills a sense of dread in the real world, beyond the television screens, too. For most pilots, wintertime can be a little scary.

Flying in the winter, when the temperature is below freezing, brings with it the threat of icing. The icing is when a layer of ice and sleet forms around the exterior of an aircraft. While this is expected on the ground, it can also happen mid-flight. While ice and sleet seem harmless, they can actually damage the aircraft, ruin the aerodynamics of an aircraft, and actually create potentially disastrous scenarios. That’s why it’s important to de-ice. But how does de-icing work?

                One of the first ways to approach de-icing systems is the pre-bath prep. Spray the aircraft with compressed air to free the exterior of snow, ice, or sleet that cling to the wings, tail, nose, and engine intake. Afterward, prepare a de-icing fluid bath. A type-1 de-icing solution made of water and propylene glycol is perfect for light snow and ice. For heavier snowfall, type-4 de-icing solutions made of 100% propylene glycol is best.

After the aircraft is bathed and allowed to dry, pilots and maintenance crew can choose to put on de-icing boots, which are ideal in inclement weather. Generally installed on the leading edges of the aircraft wings, they are thick rubber bands that are inflated and deflated to loosen any ice that accumulates on these surfaces. Of course, the de-icing boots should be regularly inspected and maintained. Even the smallest scratches can lead to leaks, which would decrease their efficacy. Larger airliners and military aircraft tend to have heating systems equipment integrated inside the wings instead of using a boot.

                ASAP Sourcing Solutions, owned and operated by ASAP Semiconductor, is a leading supplier of parts and components for the aerospace, aviation, and defense industries. With a wide variety of aviation de-icing solutions to choose from and 24/7x365 customer service, we can always help you find all the parts you need, new or obsolete. For a quote, email us at sales@asap-sourcingsolutions.com or call us at +1-412-212-0606.

In recent years, airplane windows have become a point of interest. Tragedies like in early 2018, when a Sichuan Airlines A319 cockpit window blew out at 30,000 feet, or when a Southwest 737 a window was struck by a piece of shrapnel and killed a passenger who was partly sucked out the window have caught public attention.

These events have raised many questions on the safety of aircraft windows parts and how changes can be made to improve it. 

Airplanes and submarines are similar in structure, both are designed to withstand high pressure in otherwise inhospitable environments. Not only do airplanes have to maintain safety with harsh conditions at high altitudes, but there are obstacles they must consider as well, such as birds and other debris. Aircraft windows have strict guidelines that make them operational on the aircraft. This can be found on the FAA’s AC (advisory Circular) 25.775-1. 

In short, this requirement puts the windows through stringent stress tests that would mimic the use on an aircraft 30,000 feet in the sky. These are vital to the confidence of the aircraft performing the way its intended and include bird tests, pressure tests, temperature tests, and chemical resistance. Bird strike tests are done with 4-pound bird and is travelling anywhere from 250-350 knots.

One of the world’s largest airplane window distributor is PPG. They developed a transparent material called the Opticore Advanced Transparency Material. This material is significantly stronger than prior window materials. It famously has the properties to withstand cracks and breaks at unbelievable levels. This amazing product can be shaped into many different applications and thicknesses and can be used in any need where transparency is needed in an aircraft.

Aircraft windows in the passenger section have two windows. The second acting as a backup. Many factors go into the safety and fastening of windows. In 1990 flight safety Australia said that the cause of a window blowout in the cockpit was due to unauthorized aircraft fasteners parts that were used to hold the window in place. Accidents like this and the ones from 2018 are terrifying, but the truth is that they’re so uncommon and rare that when they do happen, they’re immediately sensationalized. 

For all of your aircraft window needs, visit ASAP Sourcing Solutions, owned and operated by ASAP Semiconductor, at www.asap-sourcingsolutions.com. ASAP will provide you with operational windows and other aircraft components fast, easy, and for a competitive price.

Some may have questions on the reasons for de-icing an aircraft, how is it done and why? When traveling from a wintery weather the ice, snow, or sleet could be problematic for the aircraft. The aircraft needs to be deiced to initiate take off. Removing and avoiding the build-up of ice is essential because the aircraft is built in a very specific way in which the shape of the aircraft is designed for the airflow to move in a certain direction for an ideal take off. This means the ice/ build-up of snow could potentially alter the shape of the aircraft in a way that the airflow across the surface hinders the ability to create a lift. Which could cause a potential error during take-off.

When the weather causes accumulation of ice or snow on the aircraft the pilot oversees acquiring the airport's deicing facility to have it removed and prevented. The deicing fluid is a mixture of glycol and water which goes under the heat and is sprayed under pressure to remove any ice or snow off the aircraft. However, this fluid goes only as far as removing the ice/snow/sleet. To prevent from icing any further or keep snow or sleet off the anti-icing fluid is used after the deicing fluid. The anti-ice is a higher concentration of glycol, the freezing point is below 32 degrees, so it can prevent any freeze off the aircraft’s surface. 

The anti-icing fluid loses its effectiveness over time; however, the aircraft is equipped with a system that prevents frozen precipitation from building onto various parts of the aircraft. These systems are not only for winter months or wintery climate because the aircraft fly in high altitudes which is well beyond the freezing point. Deicing, while the aircraft is in high altitudes, can be done by hot air from engine moving to the piping in the wings and tail or by engine opening to warm surfaces.

ASAP- Sourcing Solutions, owned and operated by ASAP Semiconductor, should always be your first and only stop for all your hard to find or anti-icing components. ASAP- Sourcing Solutions is the premier supplier of deicing system and fluid, aircraft spares, and more! Whether new, old or hard to find, they can help you locate it. ASAP-Sourcing Solutions has a wide determination of parts to browse and is completely furnished with a well-disposed staff, so you can simply discover what you're searching for, at painfully inconvenient times of the day. If you’re interested in obtaining a quote, contact the sales department at www.asap-sourcingsolutions.com or call +1-412-212-0606.