Employing airplanes as detectors to avoid runway overshoots
In an effort to enhance runway safety, Airbus has developed the Braking Action Computation Function (BACF). This innovative system is designed to improve runway overrun prevention, particularly in adverse weather conditions.
The BACF works by continuously assessing and optimizing the aircraft's braking performance during landing. It uses the aircraft itself as a sensor to measure braking action, integrating sensor data and system inputs to adapt braking force and alerts, helping pilots manage deceleration more effectively.
One of the key advantages of BACF is its ability to monitor braking efficiency in real-time. This means that the aircraft systems can adjust brake pressure to optimize stopping power without wheel lock-up or loss of control, especially on slippery surfaces.
In addition, the BACF provides timely warnings or inhibits inappropriate inputs. For example, if thrust lever movements are inconsistent during rollout, the system can cancel unsafe commands to maintain safe deceleration. This feature has been highlighted in actual Airbus incidents where pilot inputs were corrected by the aircraft systems to prevent loss of control or overruns.
The BACF also complements other landing aids such as autobrakes and reverse thrust management, delivering a coordinated braking response tailored to runway conditions.
While specific details about the BACF were not explicitly described, the evidence from Airbus' incident management and system intervention during landing rollout strongly implies that such a function is aimed at improving braking performance and preventing runway overruns, particularly under challenging conditions where pilot error or environmental factors might degrade braking effectiveness.
The importance of accurate weather and runway condition information was underscored in an incident on December 8, 2005, when an aircraft slid off the runway at Chicago-Midway while landing in a snowstorm and crashed into automobile traffic. The runway was slippery due to a layer of snow covering it, and the incident was caused by a combination of inaccurate wind information, slippery runway, and insufficient use of brakes and thrust reversers.
To complement Runway Overrun Protection Systems (ROPS), Airbus and its subsidiary NAVBLUE have developed the BACF. The flight crew can share braking action information with air traffic controllers by radio, and controllers can use this information to provide up-to-date runway conditions to incoming aircraft.
In summary, the BACF works by dynamically computing and managing braking forces considering real-time conditions, enhancing safety margins during landing rollout and improving prevention of runway overruns in adverse weather or complex operational scenarios. This practice leads to more accurate landing distance computation and better overall runway safety. The BACF is one of the tools in the toolbox to prevent runway excursions in the future.
