Description

The aerodynamic effects of accreted ice on the continued safe flight of an aircraft are a complex subject because of the many forms that such ice accretion can take. In certain circumstances, very little surface roughness is required to generate significant aerodynamic effects; as ice-load accumulates, there is often no aerodynamic warning of a departure from normal performance. Stall warning systems are designed to operate in relation to the angle of attack of a clean aeroplane and cannot be relied upon to activate usefully in the case of an ice-loaded airframe.