The Nature of Aircraft Braking System
If not in flight, any pilot wishes for the aircraft to be on the ground and in the correct place. The last thing any airport worker needs is a runaway plane on the runway. Brakes stop or slow the motion of a machine. Often a machine keeps running and is only stopped from moving forward by pressing on brake pads. For example, in an automatic car, the driver must keep their foot on the brake pedal to stop the car moving forward at a red light or in traffic.
Aircraft brakes must be far more complex and robust than automobile brakes. The amount of energy it takes to halt a landing aircraft is significantly greater than that needed to halt a car. Aircraft brakes are usually configured in a multiple disc setup such as segmented rotor-disc brakes used in heavy duty aircraft. Brakes are adapted to the high-pressure hydraulic control system through the multiple stationary control disc surfaces that come into contact with rotating segments. Kinetic energy from the moving aircraft is converted into heat energy that is then dissipated into the surrounding air. The excess heat that is generated in the energy conversion is dissipated through specific spaces in between the discs.
Brakes require back-up alternatives in the case of a system failure. An accumulator is an emergency source of power for the brakes. It is pre-charged with air or nitrogen, which is accompanied by a hydraulic fluid. Under enough stored pressure, the fluid is forced out of the power brake accumulator and through the brake system to slow the aircraft. Along with backup measures, the material of the brakes is carefully considered. In modern aircraft the brakes are made of a carbon fiber material which is lightweight and efficient in dissipating the large amount of kinetic energy. The temperature range of carbon fiber brakes is impressive and can accommodate any excess heat.
The FAA sets out various regulations that outline the required capabilities of aircraft braking systems. In the event that any form of the brake operating energy is lost, it must be possible to bring the airplane to rest with a braked rolling stop. The aircraft must also have a parking brake to ensure the aircraft will not roll on a dry and level paved runway. Testing such as the maximum kinetic energy stop is required to determine the energy absorption rate of each wheel, brake and tire.
Anti-skid braking systems for aircrafts, auto brake, brake temperature indicators, brake fans, and parking brake are all examples of brake enhancement systems. With these systems, aquaplaning, rejected take-offs, brake temperature, and aircraft runaways can all be avoided. Further preflight and post-flight measures can be taken to ensure the correct functioning of the brakes. All in all, the aircraft braking systems is a well-planned and measured system that considers each and every aspect required to keep the aircraft on the ground and in the right place.
- charles price
- Posted on July 10, 2019 aviation
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