1. A method for operation of a reusable fault processing database in conjunction with a complex system, the method comprising: storing a set of logical rules into one or more logic entities of the reusable fault processing database, the set comprising one or more executable instructions applicable to fault detection and fault isolation in the complex system; storing at least one defined variable for each of the received set of logical rules, the at least one defined variable being stored into one or more variable entities of the reusable fault processing database, wherein the at least one defined variable comprises an input signal or an output signal of the one or more logic entities representing the set of logical rules, and wherein the at least one defined variable is used to calculate a state of each of the one or more logic entities; storing a configuration of at least one external interface of the reusable fault processing database, the configuration comprising a communication protocol applicable to the complex system and the configuration being stored in one or more input/output (I/O) entities of the reusable fault processing database, the external interface comprising a communication connection compatible with the communication protocol, the external interface further comprising a defined set of input to the reusable fault processing database and a defined set of output from the reusable fault processing database, wherein the defined set of input comprises communication signals indicating an existence and a location of a fault in the complex system, wherein the defined set of output comprise a fault report including fault detection data and fault isolation data for the complex system, and wherein the configuration of the external interface defines: units of a complex system from which the defined set of input is received; and form and content of results generated by execution of the set of logical rules; executing each of the set of logical rules, in response to a received function call, to generate the results; and identifying the location of the fault in the complex system, based on the results.