4D Automatic Flight Path Control in Pilot Assistance System

Research on pilot assistance systems at Eurocopter has lead to the development of an automatic 4D flight path control as part of a prototype pilot assistance system aboard an EC145 demonstrator. The series 3-axis Automatic Flight Control System (AFCS) of the helicopter has, therefore, been upgraded to a 4-axis configuration with automatic control of the heave axis. Automatic flight path control has been achieved with a dedicated upper mode, which is available for cruise flight at airspeeds above 30kt. This mode receives guidance commands from a computer of the pilot assistance system that hosts the guidance algorithms and acts as interfacing module between the flight path planner of the assistance system and the AFCS. Flight paths are defined as sequences of basic trajectory elements from a library. A distance-based analytical formulation of these elements has been chosen, thus allowing a simple and efficient description of versatile 4-dimensional flight paths. Performance of both 4-axis operation and automatic flight path control were successfully demonstrated during simulator campaigns and flight tests.