Originally Posted by
HighSpeedAluminum
Ok well, they would de-ice with Type 3 first, then spray on the Type IV which acts as a coating, to dilute any further (in this case) light freezing rain. At about 100 knots, during takeoff, the Type IV fluid shears off the wings and other surfaces, before rotation.
As for the debate about de-icing aircraft quickly enough, for it to remain effective; ie maximum "holdover time" in precip, sometimes the safest plan is to finish the de-icing with an overspray of Type IV. Like this picture, I posted previously. "Green is good". In light freezing rain, after de-icing, and an overspray of Type IV, you have a holdover time of 45 minutes , on my old charts.
