Conventional reliability analysis relies on the probability model, which is often inappropriate for handling complex systems due to the lack of sufficient probabilistic information. For large complex systems made up of many components, the uncertainty of each individual parameter amplifies the uncertainty of the total system reliability. To overcome this problem, the concept of fuzzy approach has been used in the evaluation of the reliability of a system. In this article, we use a biscuit manufacturing plant consisting of six sub-systems to capture the effect of coverage factor, failure and repair on its fuzzy availability. Mathematical formulation of the problem is carried out using mnemonic rule and the governing differential equations are solved using Matlab 7.4 by Runge-Kutta method of order four (Ode 45 function).