The Aerospace and Defense (A&D) markets are starting to use plastic packages more significantly for Space and Military ruggedized applications. But plastic packages are also inherently less reliable than ceramic devices for A&D applications. The key to the successful use of plastic devices in A&D application is to qualify the devices for the intended application using industry accepted plastic encapsulated microcircuit (PEM) qualification techniques. This paper briefly recaps the test techniques known to be effective in assessing plastic part reliability. But more importantly, it presents actual PEM qualification data gathered over the last 15 years involving over 400 individual PEM Qual lots. The paper also shows the failures modes associated with plastic packages and Cu bond wires. SEM, X-Ray, and Acoustic Microscope images were obtained for the failure modes associated with plastic packages and Cu bond wire.