In aircraft structures, a variety of lug joints are casted extensively to couple primary structural components. These lug joints are normally fabricated by a single pin or bolt type of fasteners, which leads to a simple joint that is easy to assemble and disassemble. The lug can act as a pivot since clamping of the joint is normally not allowed or acceptable. However, the elastic stress concentration for attachment lugs is very high, and this high stress concentration at the edge of the hole influences crack initiation and crack growth life. The analysis of these problems becomes more complex when there is a loss of contact between the pin and the lug which ends up in contact stress non-linear moving boundary value problems. Integrity of these lug joints becomes primary concern, since their failure can cause a catastrophic failure of the structure. This has led to mandatory implementation of structural health monitoring (SHM) concept at these censorious locations during the design and operational phase of the flight vehicles. The interference fits in particular, tend to reduce the alternating part of the stress variation at critical locations at the expense of increase in mean stress associated with pre-loading condition. There is a reasonable premise for expecting a better fatigue strength and fatigue life from interference fits. This paper addresses prognostic analysis of both interference and clearance fit lug joints to estimate the residual life of these joints and feed into the analysis of SHM methodology.