In recent years, a new and highly cost-effective scheme for field or in-situ repairs of cracked aircraft components has been developed. This scheme is based on the application of boron fibre reinforced plastic patches. However, if a patch is only placed on one side of the structure, as is often the case in repairs to wing skins, then the neutral axis is displaced and the efficiency of the patch is reduced. This paper begins by examining a simple formula which is sometimes used to predict this loss in efficiency. A new procedure to counter this effect is then proposed. This involves the use of an unbalanced laminate designed so as to resist the induced bending field.