Would anyone use actual weights ?
Might be a market opportunity here then for a set of scales to weigh passengers at check-in.... that would end the fuzziness around whether the plane is 1300kgs overweight (maybe 3+ tonnes if a widebody) and allow for more accurate fuel and trim calculations. If you fly SAA on the 340 for a long hop you get your hand baggage weighed as well so why not the pax themselves, since the technology is there ????
Certainly 70 odd kgs doesn;t seem a very accurate average these days, espec in the US..... But is there a will to do this or do we wait until an incident?
Wasn''t there a Merchantman or similar freighter once that crashed on take-off because the weight of the cattle on board was determined by weighing one cow and multiplying it by the number on board. The subsequent investigation discovered that the one that wasn't pregnant got weighed whilst most of the rest were a lot heavier.....net result more tonnage than could be carried. It might be myth but it's a good story !!