Recent developments in the concept of UAS operations in urban areas have led to risk concerns of UAS collision with human. To better understand this risk, head and neck injuries due to UAS collisions have been investigated by different research teams using crash dummies. Because of the limitations in biofidelity of a crash dummy, head injury level for a crash dummy impact may differ from the human body impact. Therefore, the aim of this paper is to investigate differences in head and neck injuries subject to UAS collision with an often used crash dummy and a human body. To perform such investigation, multibody system (MBS) models have been used to simulate UAS impacts on validated models of the crash dummy and the human body. The findings confirm the moderate risks of head and neck injuries that have been reported. However, neck load differs significantly between the crash dummy model and the human body model, and the human body model sustains larger head injury but smaller neck injury compared to the crash dummy model.