External Floating Caliper Brake Assemblies

The brake assembly and disc combination (part of the main wheel assembly) are designed and qualification tested to properly and safely decelerate the aircraft under various conditions. Unauthorized substitution of components can compromise brake effectiveness, is a violation of the qualification basis, and is prohibited.
The brake assembly is an external floating caliper-type design and can be made of either cast magnesium or aluminum. The brake assembly consists of one or more pistons depending upon the aircraft requirements. A brake assembly can also consist of multiple calipers, one forward and one aft of the landing gear, and contain multiple pistons in each caliper.
To actuate the brake assembly, hydraulic pressure, applied via the pilot’s and co-pilot’s master cylinders, enters the brake via lines connected to an inlet fitting on the caliper. The pressure then flows through the cylinder and forces the pistons outward against the pressure plate. The caliper should be free to slide on the torque plate assembly bushings allowing both pressure and back plate linings to contact the brake, which will contact the brake disc at precisely the same time.
The braking action generates a torque which transmits a braking force converting the kinetic energy into heat, which is absorbed by the brake disc and surrounding components. This braking force is transmitted to the wheel and into the tire, bringing the aircraft to a stop. Releasing the toe pedal relieves the hydraulic pressure from the brake caliper, thereby removing pressure from the disc.