An aircraft crew vision mask is provided which is especially designed to be used during emergency flight conditions where smoke is present in the cockpit. Using the equalizer coefficients, the remote testing device can determine a phase response, phase angles for each frequency increment over a channel bandwidth, and group delay. A wiper bar is disposed adjacent the squeegee roller to clean the squeegee blades. The elongated channel has a forward opening, a rearward opening and an elongated side opening extending from the forward opening to the rearward opening. , the total duration of the deposition being less than 5 seconds and preferably less than 1 second, characterized in that at least one chemical additive, called a \u201crefiner\u201d, is incorporated into said solution, said refiner having, mutatis mutandis, the effect of restricting the formation of said coating. Velocity aliasing correction may be performed based on an energy function determined using cross-border color Doppler data.