1. A method for diagnosis of a system made up of a plurality of interlinked modules, comprising: receiving an alarm from the system indicative of a fault in one of the modules; responsive to the alarm, constructing a causal network associating the fault with malfunctions in one or more of the modules that may have led to the fault and relating a conditional probability of the fault to respective probabilities of the malfunctions; based on the alarm and the causal network, updating at least one of the probabilities of the malfunctions; and proposing a diagnosis of the alarm responsive to the updated probabilities.