A FMECA-Based Analysis of the Plant Controlling Variable Pitch Propeller (VPP) System for Ships Propulsion

The object of this paper is a method that allows to determine the criticality of a system. As a case study, is considered a Variable Pitch Propeller (VPP) Plant: at first it is studied to understand its characteristics and operating logics and, subsequently, four possible Operating Modes have been analyzed. For each Operating Mode a fault tree has been modelled in TARAS, a software that allows calculating the MTBF (Mean Time Between Failures) of the plant. Subsequently, the results have been validated using a block diagram. Finally, a FMECA (Failure Mode, Effects, and Criticality Analysis) has been carried out: it includes an analysis aimed at highlighting the possible failure modes and their consequences on the operation of the Plant, and a criticality analysis aimed at identifying which items are the most critical for each Operating Mode and which Operating Mode is the most critical.