ABSEILER FALL DUE TO SELF-BELAY DEVICE FAILURE TO ENGAGE

An event occurred at a Scout owned Artificial Abseiling Tower when a Scout Trained Abseiler was undertaking skills development practice at the end of a Guided Abseiling Session.

The trained abseiler abseiled down a rope to a knot, which the participant had to pass and then continue down the same rope.

To achieve this the trained abseiler must create suitable points of contact and maintain this point while removing others, but a minimum of two must always be in place.

After passing the knot and unlocking the device, the prusik was able to reach the device which prevented the prusik from locking however, the participant also failed to hold onto the rope to also prevent them self from falling.

The abseiler was using a personal self-belay device – Kong Hydrobot with 6 mm prusik loop - https://k2.com.au/products/kong-hydrobot-descender

When using a self-belay device the prusik can be above or below the device. When the prusik is below the device, the device must be extended as to give room for the prusik to engage.

A video explaining the error with the use of this self-belay device can be found at this link - https://www.facebook.com/reel/3571070656544670

The issue for the event was not the device being used, but the way the device was rigged, that lead to a drop of a couple of metres.

The Vertical Pursuit Guide who had been conducting the activity session provided direct supervision of the activity of the trained abseiler, by standing next to the abseiler during the skill session of the knot bypass.

Conducting the skill session close to the ground was seen as an effective risk control. Post the event and after a debrief, the Guide and the abseiler repeated the exercise and realised that because the French prussik was tied onto abseilers front belay loop, there wasn't adequate distance for it to bind on the rope before it fed through the Hydrobot.

The abseilers weight pulled the Hydrobot down and the prussik was just being pushed down the rope without locking off. The Vertical Pursuit Guide has suggested to the abseiler that their prusik should be tied to their leg loop but the abseiler did not feel comfortable tying onto the leg loop, not being rated and the abseiler choose the belay loop in consultation with the Vertical Pursuit Guide. The choice of prusik placement was a direct result of the prusik and the device interacting in an effective manner to not slide down the rope.

Key Learnings:

1. The KONG Hydrabot is a very effective device however, it needs to rigged in consideration of the management of the prusik used and the distance from the descender being effectively further away for safe operation of the device
   
2. A top belay should be in place for training sessions as a backup where participants are developing their skills in knot passing techniques
   
3. Trainers and Guides should consider Self-Rescue Techniques as advanced skill and ensure suitable direct supervision models are in place during these sessions
   
4. Conducting the knot by pass skill low to the ground when learning techniques in the early part of skill development, is part of a risk management approach supported by the implementation of a top belay back up
   
5. Effective supervision of participants while undertaking all forms of training creates safer activities
   
6. Manufacturer Guidance on the Kong Hydrobot - 10220710001NS.pdf (pinnaclesports.com.au)