A new altitude capture law for flight management systems provides an early, smooth reduction of an aircraft’s arrival at an intended altitude when other air traffic is confirmed in the nearby vicinity. The goal is to reduce the number of undesired Resolution Advisories generated by TCAS (Traffic Alert and Collision Avoidance Systems) – which have been installed on aircraft since the 1990s to prevent the risk of mid-air collisions.
TCAS Alert Prevention (TCAP) involves the introduction of a new altitude capture law for flight guidance computers, which decreases aircraft convergence towards the selected altitude when traffic is confirmed in the vicinity. It is complementary to the flight guidance computer’s conventional altitude capture function, with activation of a Resolution Advisory occurring only when relevant. TCAP provides significant operational benefits in terms of airspace and aircraft control. It reduces the number of Resolution Advisories generated by Traffic Alert and Collision Avoidance Systems (TCAS) for aircraft to level off in avoidance maneuvers. With the continuous increase in air traffic density, the number of operationally undesired – or “nuisance” – Resolution Advisories continues to grow, particularly in cases when one aircraft is leveling off at the assigned altitude and another aircraft is flying at its assigned higher, and adjacent, altitude level, or is in the process of descending to reach this adjacent altitude.
Flight guidance computers for aircraft equipped with Traffic Alert and Collision Avoidance Systems.
Reduces unnecessary TCAS Resolution Advisories. Lowers stress for flight crews, and creates fewer unnecessary traffic perturbations arising from “undue” avoidance maneuvers. Incorporation of the new altitude capture law involves only the flight guidance computer. No additional crew training is required.
Capabilities of the new attitude capture law have been demonstrated with performance assessments in groundbased flight simulations. Additional evaluations are planned, leading to certification on various aircraft types.