Yes, it does take place, thats one of the reasons my 421 Golden Eagle has an alternate air flapper valve on the side of the cowl to let alt air in in the event of this happening, also have a manual selection we can use. Having said the preceeding its not seen very often, our main intake ice problem is just a side effect of normal airframe icing, of which there has been plenty this Winter.
Last edited by clunckdriver; 2nd March 2011 at 15:48.