Technical Discussion - Ring Roll-Out & Ring Reversal

The terms "RING ROLL-OUT" and "RING REVERSAL" are often used to describe a form of self-release in which the load may disengage from the winch/hoist hook. The disengagement is usually initiated by a load relief or a load jolt which can cause the lifting ring of the hoisted load to rest on the safety gate of the hoist hook rather than in the throat or gap of the hoist hook. When the load is reapplied, the lifting ring can function to open a non-locking gate assembly and cause self-release/disengagement of the load from the winch/hoist hook. Serious injury or death can result from such an occurrence.

Users may take several precautionary efforts to reduce or prevent the risk of ring roll-out/reversal. Operators are suggested to:

Train and familiarize personnel with the occurrence and factors leading to the occurrence of ring roll-out/reversal.
Make proper selection of lifting ring and hoist hook combinations to physically prevent ring roll-out/reversal.
Utilize a hoist hook with a locking gate.

Provided below is a link to an airworthiness article on "Helicopter Personnel Winching" published by the Australian Government Civil Aviation Safety Authority (CASA). The article provides an in depth discussion on the ring roll-out/reversal phenomenon and also describes the implementation of LSC's D-LOK hoist hook as one solution to improve safety and to prevent ring roll-out/reversal and snagging hazards.

CASA Article: http://www.casa.gov.au/airworth/aac/part-1/1-103.htm

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