The applications of linear induction machines (LIM) in propulsion have been investigated vastly in the past few decades. The advantages of LIM when applied in the propulsion system are that of easy maintenance and high acceleration/deceleration, to name a few. One of the applications is to combine the LIM with magnetically levitated system (Maglev) to achieve frictionless transportation system. However, in case Maglev can not maintain a uniform airgap length, major magnetic characteristics of the machine will be influenced. In this paper, the impact of this type of imperfection on the existing control strategies will be investigated. Furthermore, a simple detection technique is proposed.