It isn’t possible to use whole volume since the floor is structural. Also, the wing spars run through the hold. There is also important equipment in the lower a

It isn’t possible to use whole volume since the floor is structural. Also, the wing spars run through the hold. There is also important equipment in the lower area. It is impossible to use cargo hold. It doesn’t have the escape routes and would be death trap. Plus, the hold is full of bags.