A few days ago whilst discussing the merits and otherwise of constant speed props, I've never flown one by the way. An accident was discussed whereby the prop was capable of being reversed. The aircraft was on final at a height in excess of 50 ft when the pilot selected reverse pitch. Now, I don't know if this is true, or whether there is some safety feature to prevent this or not. I don't think the pilot can tell us either. So perhaps the more experienced can comment on whether this is possible. I would think the consequences wouldn't need to be discussed much.