Majikthise, do you mind elaborating on which airport you experienced this leaving?
I work for a smaller charter operator up here that operates some relatively unique 4 engine jets (i'll let you figure that one out; i'm sure you'll figure out who
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I've been noticing a disturbing trend of ridiculous excess Type IV applications on our aircraft out of some smaller centres (YMM, YXS, YXU to name a few) over the last couple years. Although our pilots have not been too concerned about it; I've spent many an hour flushing control surfaces. The usual pilot complaint is autopilot porpoising in cruise (this aircraft if quite susceptible to this with greasy Type IV floating in there).
Informally, our pilots have been keeping track of de-ice receipts, and fluid usage - I've seen variances of as much as 50 to 100 gallons at the extreme. It's usually quite obvious once a gallon or so drains out of the flap canoes.
At the larger airports, we usually don't have much problem with excess or incorrect application.