Capt Claret is correct in relation to the props and a further problem is that because this type of landing is never practiced, moving the mixtures to ICO and then attempting to feather the props, usually results in a high sink rate with the possibility of a hard landing short of the runway. There has been numerous reported cases of this happening with injuries to both pilots and passengers. Lets face it, it a gear collapses, the prop(s) will strike the ground regardless, so the engine will have to be stripped whether or not ht eprops were rotating. Its better to fly the aircraft down to the touchdown point flare, close the throttles and let the aircraft settle on.