How Automatic Brakes Work for Aircraft
While technological advancements to vehicles can always result in higher performance capabilities, easier handling, and other such improvements, one of the most important results of innovation is increased safety. For aviation in particular, the advent of the aircraft Automatic Brake System (ABS) has allowed for more efficient and safe braking procedures by providing proper engagement times and automatic deployment. While simple in operation, the ABS ensures that pilots can safely touchdown on runways during a variety of weather conditions and that braking always deploys with optimal timing for efficient stopping power without having to use the brake pedals.
For the aircraft Automatic Brake System to deploy with correct timing, it will be actuated upon the extension of the aircraft spoilers. The spoilers themselves are also automatic in their deployment, relying on the detection of the main gear when it is spinning up. Nevertheless, there are often delays for the deployment of the aircraft brakes, and timing is typically determined by settings. For example, the ABS system of the MD-80 features three delays settings which range from one to three seconds of time between the deployment of the aircraft spoilers and brakes. Generally, the choice of time delay for the deployment of aircraft brakes will depend upon the length and condition of the runway in question. For instance, runway conditions such as snow will warrant a quicker deployment time.
For any braking system to achieve optimal stopping power, regardless of whether they are manually or automatically operated, anti-skid characteristics are crucial. With the ABS’ anti-skid system, pressure is released onto the aircraft brakes when there is a detection of skidding. As the wheel begins to spin up again, the anti-skid system will enact more braking pressure and continue a cycle in rapid succession to deter any issues. Coupled with the ABS, both systems can provide an aircraft with ample stopping power to land on a variety of runways, all without requiring the pilot to use brake pedals.
While stopping power is great, most aircraft will want to continue moving across a runway after landing to complete their taxi procedure and make room for the next incoming aircraft. Many braking systems will allow for pilots to reassume control by pressing on the brake pedals, those of which are most often located on the topmost section of the rudder pedal. Typically, the pedal will only need to travel 1/4th of the way through its axis to disable the ABS, and the anti-skid system will remain functional to ensure safety. Another method is to engage the thrust levers and push them forward, as braking would only hinder speeding up the vehicle. As another alternate method, the ABS will disengage once aircraft flap angles retract past 26 degrees. Lastly, stowing the spoilers can also disable the ABS as well.3
Despite the concerns of some pilots, the ABS will still be functional even in the case of spoilers not deploying automatically. In such instances, the aircraft spoilers may be manually operated with the use of a lever or other control, and their actuation will activate the ABS. As such, auto brake systems can benefit countless flight operations, ensuring that braking power is always deployed efficiently and safely. At Unlimited NSN, we are a leading online distributor of aircraft components, marine parts, electronic hardware, and other industry items. With competitive pricing and rapid lead-times offered for our various listings, we can fulfill your operational requirements with ease while saving you time and money. Peruse our expansive manufacturer and part catalogs at your leisure, and you may request a quote for the items you are interested in at any time through the submission of a completed RFQ form on our website.
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