A method and apparatus for logging transient events of an optical fiber span within a fiber optic system, the method comprising the steps of sampling measured values of at least one signal parameter of an optical signal transported through said optical fiber span, OFS; processing the sampled measurement values to detect an occurrence of a transient event during transport of the optical signal through said optical fiber span, OFS; and providing each detected transient event with a time stamp for correlation with other monitored events within said fiber optic system.