In April, The US Forest Service released Interagency Aviation Safety Alert 21-03 (incorrectly identified on the release document as IASA 21-02) regarding the prevention of remote hook inadvertent release, aka dynamic rollout. In short, a dynamic rollout can occur in the field when a load ring is large enough, or otherwise able to roll over the load beam, push against the keeper and be released, falling free.
All Mechanical Specialties cargo hooks are designed to aid in the prevention of dynamic rollout when used with the recommended sized load ring, however there may be circumstances where other, specific load rings may be required based on the work being performed. In the case of work performed for the forest service, the use of a 4.5 inch, oval ring is required and under certain conditions, a dynamic roll out may be possible.
To prevent this, the Forest Service allows one of two corrective measures to be taken to alleviate the potential for an inadvertent load release. One option is to use a longer load beam, which Mechanical Specialties considered, but found the increased potential for breakage of the load beam to be an undesirable risk. Instead, we offer an extended guard for all of our x01 series cargo hooks that help protect the cargo hook from impacts during normal working conditions, but also meet the Forest Service requirements by not allowing a load ring to maneuver up over the load beam after initial attachment.
If you have any questions about meeting these contract specifications, reach out to our team. If you would like to purchase a replacement, extended guard, the part numbers for the various model hooks are listed below, easy to swap out. If your hook happens to be due for an overhaul, we will gladly install the guard for you at no additional labor cost.