Flight Test Results for Task Oriented Flying Qualities Evaluation

This paper presents a technique used by DFVLR for establishing a data base and recommendations for task oriented flying qualities. This technique is characterized by the definition of mission related and representative tasks, by the carrying out of flight test programs for the defined tasks, and by the statistical analysis of collected measurement data and pilot ratings. Starting from the German Anti Tank Helicopter (PAH) mission the 'Hovering Tracking' task was defined. A flight test program was conducted for the evaluation of the target tracking performance of helicopters. The task for the five test pilots was to track a fixed or moving target and to minimize tracking-, position-, and altitude errors. The flight tests were performed with the DFVLR testbed BO 105-S 123. The test variations included different loading conditions of the helicopter, different hovering altitudes, and different environmental conditions. Aircraft state and control data and target deviations were measured, pilot ratings were collected. The reduction of the data yields statistical parameters characterizing closed-loop system dynamic behaviour. Those statistical parameters exhibiting a high correlation with the pilot ratings constitute the basis for the evaluation parameters. The results of the study are presented as diagrams for the evaluation of flying qualities with regard to the Hovering Tracking task.