The introduction of commercial off-the-shelf (COTS) parts in the military industry paved the way for the use of plastic encapsulated systems in spacecraft systems. Thus, nowadays such components are experiencing a growing use in space applications. However, there are severe risks inherent to these types of packages. These are mainly related to the lack of hermeticity and the CTE mismatch with the internal inorganics parts and can lead to catastrophic failures such as popcorn cracking, metallic smearing on die surface, corrosion, wire bond cuts, and others. Such anomalies are typically related to the presence of interface delamination, voids in the moulding compound, and cracks within the system. In this context Scanning Acoustic Microscopy has proved to be a very effective way for the non-destructive inspection, screening and failure analysis of plastic encapsulated EEE part. The present communication will report on the critical role that this this tool play to assure the suitable performance of the system and to early detect future functional failures.