It has been developed the method to improve a fleet availability for PAFC power plant as on-site repairing operation. The detour operation from a defect cell in the stack has been investigated. The method of this is used a carbon block with some adhesive on the contact interface to form a electrical by-pass, thus the defect cell could be detoured from stack current path and low resistant path by the carbon block would be secured. Some improvement on the contact or fixation have been examined and the methods have been confirmed their life performances with bench scale cell tests. The results of these are discussed