Focusing on the content of China Civil Aviation Regulations CCAR-33R2 article 33.68

a test method for turboshaft engine complying with airworthiness regulation requirement was provided

including icing critical point analysis

icing certification test points determination

engine icing certification test. In combination with the turboshaft engine operating envelope

critical point analysis was conducted to determine the icing certification test points. Several icing calculation points were selected in the icing envelope

and icing positions and amounts were calculated for each point. The calculation results show that the area where the temperature is close to 0 ℃ and the altitude is low is the zone where the turboshaft engine has a significant ice amount. During the icing test

the temperature points at which ice formation just occurred and the amount of icing was the largest were found in the temperature range of -4 ℃ to -1 ℃. The test results show that the temperature point with the largest amount of icing is the most severe icing test point.