RESCUE EQUIPMENT: Rigging elevated pulley systems from the ground


CarolinaFireJournal - Bob Twomey
Bob Twomey
04/23/2012 -

During your years in the rescue service, have you ever had to get a single or double sheave pulley system elevated and secured above the ground in order to perform a rescue, when you could not easily reach that elevated spot to place the pulley?

Such a rescue could easily be encountered if you have to place an elevated pulley system above an injured tree trimmer, or above a pilot in his wreckage in the plane that crash-landed in a tree top, or even above a person stranded off the side of a building, bridge, water tank or whatever.

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Aircraft suspended in the trees attempting to reach runway.

What if you do not have the equipment immediately present for you to ascend to a point above an injured person, or the ladder truck platform to work off of, or a crane to raise you to an elevated position above the victim(s)? What if this apparatus cannot reach a rugged or remote site to place you above an elevated victim to initiate the rescue?

“Skating the rescuer” is a time-honored and proven method of moving the rescuer and victim away from the base of the tree during the lower, thereby reducing the possibility of injury should the fuselage suddenly begin to fall from the tree.
During the November 2011 DuPont Rescue School, a group of instructors ran a class on performing such rigging in a scenario I set up in a tree. The scenario was that of a pilot attempting to land on a remote runway but instead, crashed his light aircraft short of the runway into the trees, with the airplane remaining suspended in a treetop. The simulated “plane” was placed in a tree top about 35 feet above the ground, with the pilot still in the crumpled cockpit and unable to assist himself in exiting the aircraft. The location was such that no wheeled vehicles could reach the crash site. However, the pilot still required rescue from an elevated position to the ground for further medical assessment and transfer to a medical facility. Such a scenario could easily take place anywhere in your rescue area.

Pulley system being hauled up into tree by the anchor line

One immediate observation was for the initial rescuer to climb the tree with a haul line to a point above the aircraft. This idea was quickly discarded due to the instability of the plane in the tree limbs. Should the tree shake, the aircraft could become dislodged and very easily come crashing down onto the ascending rescuer. This would probably not be good.

We proceeded to demonstrate a method to deploy a tether line made up of a bean bag “throw bag” attached to four millimeter utility cord. The idea is that the throw bag and running end of the line are thrown through the stable fork of some limbs above the wreckage, with the weight of the bag (one to two pounds) falling back to the ground along with the attached running end of the tether line. The standing part of the tether line is then attached to the standing end of a one-half inch static kernmantle rope. This rope is then carefully hauled up through the fork and back to the ground so that the rescuers can grab it, thereby hauling up into the tree a double sheave pulley. The is already rigged with two ropes: one as a main rescue line, the other as the back-up safety line.

As the one-half inch static rope is hauled through the tree fork, the rigged pulley system is hauled up to the fork of the tree.

Once the pulley reaches the desired height and position above the wreckage, the single one-half inch static rope is then tied off securely, thus becoming an anchor line for the two-sheave, pre-rigged pulley.

Close-up of the anchor line and pulley system hauled up to fork

This would be no different than this same pulley being secured in place in a webbing anchor sling. The standing ends of the two ropes through the top double sheave pulley are then attached to a double sheave pulley in a change of direction at the base of the tree. This transfers the bulk of the loading (of the rescuer’s weight) to the tree base, which is much stronger than the tree fork above, plus it allows for “straight line pulling” of the rescuer vertically, thereby not shaking the treetop (and the fuselage) more than necessary Likewise, it allows more rescuers to grip these two hauling ropes that will pull the rescuer up through the tree. Also in this configuration, the rescuer is hauled up near the center of the tree along the main trunk. Should the fuselage break loose and fall, the rescuer will be closer to the center of the tree, reducing the chance of being hit by the falling fuselage.

Anchor line for pulley tied off on secure ground anchor, here another tree. Preferred anchor would be a tensionless web sling hitch instead of an anchor sling to prevent sling from “riding up” the tree.

Once this rigging is completed, the first rescuer to go up clips into the two haul lines and is gently and smoothly raised up to a spot above the wreckage, where he or she ties off onto the tree, freeing the two haul ropes to be lowered for a second or third rescuer to be raised up to the fuselage. Once the rescuers are secured to the tree at and above the wreckage, initial medical stabilization begins in preparation for disentangling and lowering the victim(s) to the ground.

It should be noted that the rescuer can be raised manually or with a mechanical advantage (MA) system. This is up to the ground team to decide, but in either case, safety prusiks are used to arrest a fall during the raising operation. It would be much safer to have the haul lines anchor on another tree, vehicle, rock, or other stable anchor with the safety plusiks well away from the base of the tree, should the fuselage fall or shift up in the tree top. This way, no rescuer is directly under the tree while operating the prusiks.

First rescuer raised well above the fuselage so he can position himself above the wreckage and tie off.

While the rescuers are working in the tree to free the pilot and lower him to the ground, the haul system is replaced with a braking system such that a rescuer and the patient can be lowered to the ground. Obviously, depending upon the victim’s medical condition, patient “packaging” is commensurate with injuries. However, keep in mind that rapid patient removal from an extremely unstable aircraft in a tree may preclude the level of patient packaging administered, due to the danger to the victim AND rescuers. This call is made based upon the circumstances at the time of rescue.

Both rescuers now raised into tree top, securing themselves to the tree as haul lines are converted to lowering lines

The patient and rescuer are lowered gently and smoothly to the ground. It is not recommended that the patient be lowered without a rescue attendant to move limbs out of the way, clear snags of the ropes on limbs, patient reassurance, maintaining an open airway, etc.

“Skating the rescuer” is a time-honored and proven method of moving the rescuer and victim away from the base of the tree during the lower, thereby reducing the possibility of injury should the fuselage suddenly begin to fall from the tree.Skating the rescuer simply involves the rescue attendant placing a carabiner on the two lowering lines running up through the anchored two-sheave block, and connecting this carabiner to the rescuer via a short web or prusik sling such that, as the lower commences, both are pulled or guided away from the tree along the angle of the two ropes running to the anchored two-sheave pulley. This works much better than a tag line being used to pull the rescuer and victim out and away from the tree, as this method does not pull as much against the top of the tree in order to keep them both out from below the wreckage.

Rescuer and victim arrive on the ground at the base of the tree to rescuers.

This is a very effective, simple way to place a pulley or block and rigging above the victim by using a simple throw device, whether it be in a tree or other setting where great danger exists to rescuers below an unstable fuselage, or whatever. As I have said in so many articles, your use and deployment of rescue ropes and rigging is limited only by your imagination, knowledge, skills and experience.

The throw bag can be a commercial kit as seen in arborist trade magazines ... or as simple as a homemade weighted device. Remember, all it has to do is work. For those higher positions that you must reach, a slingshot propelling a weighted device or even a “water balloon two-person slingshot” will suffice to launch a weight tied to a tether line. The big thing is: KEEP IT SIMPLE, and PRACTICE the techniques you choose to use in tether line deployment.

Bob Twomey is the current chief and founder of the North Carolina High Level Extraction Rescue Team, Inc., a volunteer helicopter search and rescue support team based in Transylvania county, N.C. He is the senior helicopter pilot for Wolf Tree Aviation, LLC operating out of Transylvania Community Airport. He also serves as Deputy Chief for Training in Brevard Rescue Squad. He has been active in SAR for 37 years. Twomey can be reached at 828-884-7174 or [email protected]
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