Moving target indication (MTI) is the first component of a tracking radar's signal process. Being the fundamental component of a tracking radar, the reliability of the MTI process to detect a moving target must be effectively characterized in order to achieve the goal of characterizing the reliability of a tracking radar. Operational reliability metric is used to quantify the ability of an MTI radar to detect a moving target in various scenarios. The radar scenario investigated in this paper includes the detection of a small aircraft by a ground based MTI radar. MTI processing is applied to the received signal in order to remove the effects of the stationary ground clutter. An operational reliability analysis of the filtered data is performed to show the reliability of the MTI radar. The reliability analysis is repeated for different target altitude scenarios.