If you use a helicopter with a winch you can add the sling and pick up two loads.
Don't forget that both the sling and winch both release together.
Another method is to pick the winch load up first, winch it up to the door and press O the load is placed inside the helicopter. Close the winch door CTRL+U.
Now you can pick up the sling load press O to enable sling pick up the load, take to another location drop the sling load first then open the winch door press O and the load should appear attached to the winch lower to the ground and release object.
Helicopter hoist commands FSX/Accel
HOIST ARM EXT/RET -- CTR + U
LOWER HOIST CABLE -- J (press again to stop)
RAISE HOIST CABLE -- K (press again to stop)
ATTACH AND RELEASE -- 0
The sling is enabled by saving a flight and editing the .flt file
under payload change cable lengh from 0 to whatever you want.
[Payload.0]
PayloadList=-1
[Sling.0.0]
Object=
CableLength=0
HoistSwitch=0
[Sling.1.0]
Object=
CableLength=65
HoistSwitch=0
Start from the saved flight and the cable should be attached to the helicopter, pre made objects to pick up available at hovercontrol scarcreekloads2.zip & liftableloads_1.zip
To use the objects you either have to use ai carriers to place the objects or use the saved flight method, you place the objects with the object placement tool save the xml and link it to the saved flight the instructions on how to do this is in the scarcreekloads2 file in the step by step pdf and also the cfg entries for adding the sling to the default bell206 and hook camera.