the 'rope' would be just be an camcreated object, an addon most likely
the scipt would look something like this;
_chopper = _this select 0
_cargoobject = _this select 1
#update
_cargoobject setpos [getpos _chopper select 0,getpos _chopper select 1,(getpos _chopper select 0)-3]
_cargoobject setdir getdir _chopper
~0.01
_height = getpos _chopper select 2
?_height>10:goto "update"
hint "Cargo Dropped"