Section 25.1105 - Induction system screensIf induction system screens are used-
(a) Each screen must be upstream of the carburetor;(b) No screen may be in any part of the induction system that is the only passage through which air can reach the engine, unless it can be deiced by heated air;(c) No screen may be deiced by alcohol alone; and(d) It must be impossible for fuel to strike any screen.