Add to ORKGBrown's Vorticity Transport Model, coupled to an additional particle transport model, is used to simulate the development of the dust cloud that can form around a helicopter when operating in dusty or desert conditions. The flow field around a tandem rotor configuration is simulated during the final stages of landing. The time-averaged flow field around the helicopter is characterised by the existence of two stationary points immediately adjacent to the ground plane. Almost all entrainment of dust into the flow takes place forward of the rearmost stationary point; the dust initially remains in a thin, sheet-like layer above the ground. As the dust sheet approaches the forward stationary point, the layer thickens and forms a characteristic w...