Due to the high speed ranges that aircraft typically operate in during flight, it is important that they are capable of reaching a safe stop upon landing on a runway. While aircraft can reduce their speed before landing through the use of engine power reduction and flap extension, the aircraft brake system is the safest and most reliable option when on the ground. Brakes can also benefit ground operations during taxi procedures or when parking the aircraft, making them an indispensable part of operations. In this blog, we will provide a brief overview of the aircraft brake system so that you can best understand its functionality and importance.
Across all types of aircraft, the most common configuration is the disc brake assembly. With such brake systems, stopping power is achieved through friction which is created by the discs. When the pilot depresses the brake foot pedal within the cockpit or the autobrake system is actuated, pistons within the brake assembly push on the discs so that they are squeezed together. With this force on the wheel, speed is reduced until the wheel fully stops or the brake is released. Due to the amount of friction that occurs from such processes, brake systems must have robust heat sinks to dissipate high temperatures. Additionally, brake anti-lock systems such as the ABS ensure proper stopping power without the risk of sliding.
When designing an aircraft brake system that relies on discs, manufacturers will consider the number of discs, disc diameter, and disc materials that will best serve a particular model. Furthermore, brakes are also designed for the worst cases of rejected takeoffs, ensuring that the aircraft is capable of safely aborting the procedure without facing extreme risks due to a lack of runway space left. In such instances, the aircraft brake system would need to take on a significant amount of energy for reducing speed. For large airliners that feature massive takeoff weights, the brake system will often feature multiple discs on each brake assembly or wheel for optimal operations. On a multi disc brake aircraft such as the A380, for example, sixteen out of the twenty-two wheels contain disc brakes to ensure proper stopping power.
In many early assemblies, brakes were constructed with the use of steel. In the 1980s, however, carbon brake systems became more available for commercial aircraft and were popular due to their advantages in durability, weight, thermal sensitivity, energy absorption, and cooling rates. With a large heat tolerance and the ability to distribute and transfer heat more efficiently and evenly, carbon continues to serve as a very advantageous material for such applications.
For the actuation of brake assemblies, most commercial aircraft rely on hydraulic force for squeezing discs together. Nevertheless, electrically powered electromechanical actuators can also be found on numerous aircraft such as the Airbus A220 and Boeing 787. When a hydraulic system is used, there may be an independent brake system for aircraft, a booster system, or a power brake system that only relies on the main hydraulic system for pressure. With all hydraulic types, valves, cylinders, and other hydraulic components work together to ensure that enclosed fluids are properly pressurized for the efficient transfer of forces. With electric brakes, on the other hand, electricity from the aircraft’s electrical system is converted into mechanical power through electromechanical actuators. With this mechanical power, gears can be driven so that the brake discs are pressed together.
Having a functional aircraft brake system is crucial for safe flight operations, thus such assemblies require regular maintenance and repair. Aviation Orbit is a premier supplier of aviation, NSN, and electronic parts, and we can help you secure everything you need for your maintenance endeavors with competitive pricing and rapid lead-times. Explore our robust offerings to find over 2 billion new, used, and obsolete items readily available for purchase today through our website. When you find particular items that you are interested in procuring, you may begin with a personalized quote for your comparisons through the submission of an Instant RFQ form. Get started today and see how Aviation Orbit can help you fulfill all your operational requirements quickly and easily.
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