Abstract: Based on the theory of equivalent damage calculation and the character of landing gear fatigue load spectrum. The calculation method of equivalent damage is given for three states:The mean stress of spectrum iS same;The mean stress of spectrum is not same but its minimum stress is same;Ratio of stress of spectrum is known. It is very convenient and efficient to use the method in engineering and needless to calculate the damage degree at the critical sec- tions.

Key words: landing gear, spectrum analysis, damage assessment