Allan Hine - Behind the Badge
Some of the cargo transported includes fruit and vegetables to Hong Kong (wrapped in foil with dry ice), pharmaceuticals to USA, and racehorses which are transported in custom made stables that fit up to three horses and room for food, water and an attendant to stand. A maximum 30 horses per plane are allowed due to airflow limitations.
The stacking of cargo is quite involved with weight needing to be balanced evenly across both sides of the plane with no imbalance greater than 9000 kg or 13,000 across the wing area. Whilst the captain is the most senior and must sign off on the load before the flight, the most important people are actually the load controllers who determine where everything goes and keeping the plane within its payload. As an example a 747-800 has a maximum take off weight of 450 tonne. Airlines obviously try to maximise the payload on every flight to operate at their most efficient.
Cargo is also transported on scheduled passenger aircraft and this can be around 50% on any flight. The weight of all cargo, luggage, the plane, the food and fuel is known. Passenger weights are assumed as an average (including hand luggage) of 78kg for men and 68kg for women.