1. 8990. What is the principle characteristic of a windshield pneumatic rain removal system? A. An air blast spreads a liquid rain repellant evenly over the windshield that prevents raindrops from clinging to the glass surface. B. An air blast forms a barrier that prevents raindrops from striking the windshield surface. C. A pneumatic rain removal system is simply a mechanical windshield wiper system that is powered by pneumatic system pressure.