This paper aims at introducing the probabilistic fracture estimate tool SCILAB-AFGROW that was developed for the evaluation by of DRAWIN-3DÒ software. The latter has been developed based on a strong FAA recommendation following a fatigue crack defect (Hard-Alpha anomaly) arisen on the titanium fan disk that caused the crash of UA232 flight (Sioux-City, 1989). DARWIN fracture risk assessment relies on probabilistic tools, a crack propagation solver and especially a use of an exceedance curve. This curve describes the statistics distribution of the existence and the initial size of the crack in the titanium alloy part. The deterministic and probabilistic capabilities of SCILAB-AFGROW will be demonstrated by considering the analytic example of a hollow pressurized cylinder. The proposed tool allows to efficiently cross-check and to easily understand the probabilistic fracture estimates computed by DARWIN-3DÒ. It also provides corrections to some limitations faced by DARWINÒ - such us the non-verification of the net-section and residual strength criteria in the probability of fracture computation. In addition to standard random variables already proposed by DRAWINÒ (crack exceedance, stress, life, inspection, detection, etc...), SCILAB-AFGROW is able to use structural random variables and sensitivity solutions for the probability of fracture computation.