This Addendum to ESDU 07001 includes a computer program to calculate section properties of fuselage stiffeners rapidly. These properties are required input for Program A0701 which estimates the noise reduction through cabin walls. The cross-section of a stiffener must be divided into a set of elements@ each of rectangular cross-sectional area. The width@ height and distance of centroid from the skin surface are then required input for each element. The program then returns values of the cross-sectional area@ the distance of the centroid from the skin surface@ the second moment of area and the torsional constant for the entire section.