Mechanical components and electronic equipment installed on rotorcrafts regularly operate in a sine on random vibration environment. To ensure their durability and performance, many of these undergo qualification testing to verify their ability to withstand operational conditions. Therefore, it is necessary to derive and establish flight data equivalent test. When multiple requirements must be met, consolidating them into a single equivalent test is often beneficial. While existing methods effectively address purely random environment, the sine on random scenario requires further exploration. This work presents a new method, capable of deriving an equivalent fatigue damage spectrum sine on random profile for a given mission reference, composed of different types of input (power spectral densities, time histories, sine on random). After a brief theoretical introduction to the shock response spectrum and fatigue damage spectrum, the proposed method is introduced and applied to two case studies, demonstrating its effectiveness and reliability.