Was AS350B2 ZK-HIG at Auckland in Nov 2011:
https://asn.flightsafety.org/wikibase/140004
I had seen video of same accident before but hadn't understood what caused it until the explanation given in this Pilot Debrief video. Accident report at ASN link says sling attachment arrangement was the cause but doesn't explain it very well nor does it have any photos of the incorrect connection.