Research on Very High Plateau Test Flight Method of Twin-engine Light Civil Helicopter

During the performance flight test at very high plateau,the helicopter is near the using limitation,the flight risk is high. It is necessary to study and develop reasonable and safe test flight methods to obtain accurate helicopter performance data while ensuring test flight safety. According to the airworthiness regulations on the requirements of helicopter high plateau test flight and data extrapolation,the required test flight environment condition and test flight subjects are analyzed and determined. Both of the very high plateau test flight method and data processing method are studied,and the determined test flight method is applied for very high plateau test flight of H425-100 helicopter. The results show that the testing methods determined in this paper are reasonable and feasible,in which the tethered hover method can improve the efficiency of test flight,the one-shot simulating mode can effectively reduce the risk of test flight,and the fitting method can be used to determine the helicopter take-off and landing distance more accurately.