USE OF HELICOPTER FLIGHT SIMULATION FOR HEIGHT-VELOCITY TEST PREDICTIONS AND FLIGHT TEST RISK REDUCTION

Height-velocity testing for helicopters has historically been a high risk test area which in many cases has resulted in an aircraft accident. As part of the testing of the YUH-61A, the development of a height-velocity diagram for operations at 4000 feet/95°F was required. In order to reduce the flight test time required for the test and the risk involved, a dynamic performance simulation of the YUH-61A was used to predict the height/velocity envelope and to give the pilot experience, prior to flight test. of the profile to be flown. Flight testing was accomplished in June 1976 at Bishop, California (4000 feet elevation). Test results agreed well with the simulation predictions and the testing was completed in only four flights, considerably less time than normally would have been expected. This paper describes: ◦ piloted and unpiloted simulation ◦ height velocity and envelope prediction techniques ◦ “minimum risk" flight test planning and testing ◦ flight test data reduction ◦ correlation of simulation results with flight test data. Also discussed in this paper are future trends in methods of height velocity envelope determination as a result of the expanding capabilities of computerized flight simulation techniques.