The aircraft flight manual said not to relay on airframe visual icing cues before turning engine anti-ice on, and the consequences of using an engine anti-ice until build up is visible from the cockpit may result in severe engine damage.
The aircraft flight manual said not to relay on airframe visual icing cues before turning engine anti-ice on. It states that the consequences of not using an engine anti-ice until build up was visible from the cockpit might result in severe engine damage.