Curious about sling loading of helicopters, I googled for images. This site shows a variety of sling loads carried by Chinook. Interesting that Blackhawk cases haven't been slung from their mast. There must be a reason for that:
https://www.chinook-helicopter.com/s...ad_Weight.html
Lynx sling load seems to show several "streamers" attached. They don't seem to be chutes. Perhaps they are instead to allow the behaviour of sling load to be monitored more carefully?? Or do they serve to damp out any oscillations?