NOTE: I am not at liberty to redistribute the documentation used to build this model.
Beginning in 2014, I completely rebuilt my Piaggio "Avanti II" P180 model from scratch, using all Catmull-Clark subdivision surfaces. It's far more accurate, far more detailed, and much more highly-rigged for animation. Click here to go to that article.
The 2009 article has been removed from my site, but the complete original article for the 2009 P180 model is included in "Modeling with MODO, Volume One".