'Mustafagander', I agree, the RAD ALT on the 747 always reads -8 feet on the ground. This is the length of the 'truck'. On landing, 'heel' first (unlike the 767 which is toe first) the RAD ALT indicates 'zero' and -8 feet once the whole lot is in contact. Very accurate. All this is abit technical, there are many obvious clues that one is going 'up', including the loud gear relay switches. I agree you need two sources and need to have it correct in the manual, but isn't it sad everything including the bleeding obvious has to be a SOP.