Flight Performance and System Safety Considerations for a Civil Aircraft with Active High-Lift System

Kurzfassung

This report gives an overview over the fundamental flight mechanical characteristics of a civil transport type aircraft with an active high-lift system. The two presented topics performance and system failure impact several investigations have been carried out. Within the performance considerations the generated trim envelopes will show the limitations in terms of airspeed and angle of attack range for the approach configuration and the performance gap to the cruise configuration. Due to the results the effect of a wing profile change from a clean nose design to a droop nose design will be presented and discussed. Additionally, the ”Power Curve” has been analysed in order to determine the requirement of support systems to manage e.g. the thrust due to strong gradients of drag over airspeed for ”backside operations”. The investigations of the second topic assess the dynamic aircraft response for several different types of symmetrical failure cases such as active high lift failure but with all engines operative, recovery actions, reconfiguration and temporary failures due to engine failures at too low power settings. Each of these cases is discussed in terms of acceptability during approach phase and also a procedural solution is tested for the avoidance of the temporary low engine failure. The overall consequences of all the presented investigations will be outlined and further research activity will be derived.