This problem arose in connection with the stabilisation of the spar flanges of an aeroplane, where the spar passes through the fuselage. The fore-and-aft stabilisation of a compression flange in these circumstances may often be effected by means of intermediate supports, which are necessarily flexible, and the reliability of any calculations of buckling load is somewhat doubtful, mainly due to the difficulty of estimating the stiffness of the supports. In view of this it was decided in a recent design to consider a continuous support for the spar flange in the form of a thin horizontal web riveted to the flange and to the sides of the fuselage, and having a small member attached to its other edge.