Prestressed ground anchors are broadly used for stabilizing slopes around reservoir. Appropriate inspection and timely maintenance of them is required against deterioration due to aging and severe field condition such as fluctuating reservoir and ground water level. In general, numerous anchors are placed in a slope which is very steep and large area. This field condition made the inspection work difficult and requiring great effort. In order to reduce this effort, primary screening to extract certain anchors which need further diagnosis was tried using a popular-price multicopter. Through this study, the optimal way of observation was identified such as a newly developed form for recording an inspection result and appropriate distance for shooting pictures of a target structure. Roughly, 70% of work load could be reduced by this method.
