ARMY AVIATION SYSTEMS TEST ACTIVITY EDWARDS AFB CA
Engineering flight tests were conducted to develop realistic single- engine height-velocity diagrams for the CH-47C helicopter with T55-L-11A engines. During these tests, no deficiencies were identified. The height- velocity diagrams developed are suitable for inclusion in the operators manual when accompanied by the flight conditions and a discussion of the pilot technique. Entry characteristics of the helicopter following engine failure are satisfactory. Power settling may occur following an engine failure from an out- of-ground-effect hover unless the helicopter is pitched immediately to an accelerating attitude before the thrust control rod is lowered. The takeoff procedures depicted in the operators manual and the US Army Aviation School CH- 47 standardization guide are safe in the event of single-engine failure. Height- velocity performance was apparently unaffected by the center-of-gravity location or which engine was failed. Further testing at high outside air temperatures would be required to completely define the single-engine height-velocity performance of the CH-47C helicopter equipped with T55-L-11A engines.