I was working above the curved glass greenhouse/backporch
My customer asked my advice on what to trim on a silver maple, and I suggested that silver maple would be much better off without that storm damaged lead hanging over the expensive back porch made with curved glass. It was beautiful, and the limbs would destroy it if they fell.
I told him it was not an imminent threat, but it the decay on nearby (poorly pruned) stubs would surely spread, making it a threat in the future. Additionally, the worst limbs over the glass were 10 year old sprouts from old storm damage, and were not real well attached anyway. He was fond of the shade they provided. I was being honest about the risk, but basically, I talked him into doing the job.
During the removal, I was perched about 10' off the side of the main trunk, feeling a little precarious, as there were no branches above me that were sturdy enough to tie to. I had removed all the interfering limbs, (also removing more weight before the biggest drop), and I was rigged for removing the 20' long branch dangling over the glass dome.
I was tied to the branch with a timber hitch holding a full hitch, then over a stub with a 1/2 hitch right beside my left shoulder to hold the slack in the line (and to add friction during the drop, too). I left a bit of slack in the line to give me room for the chainsaw, and made a nice deep undercut, about 2/3rd through the 6" branch. No hinge needed, this horizontal branch was going to fall straight down when I was done. It was going to be a pop-cut.
I began making the top cut, the limb began to droop as the bottom cut closed...AND MY GROUNDMAN YANKED ON THE LINE, PULLING IT INTO THE CHAINSAW AND CUTTING OFF THE LOWERING ROPE!!! OH NOOO!!!! HOW COULD THIS HAPPEN TO ME ?
The entire rope fell out of the tree, the wind had been blowing pretty briskly, and I only had a wafer thin strip of wood left holding the branch. I cried out frantically "I HAVE NO ROPE! SEND ME A ROPE NOW! HURRY! TIE IT ONTO MY CLIMBING LINE! $#@!!$ !@#$! 1%t!% HURRY!!!!!" (or something like that) Fortunately, the wind died down completely calm, right as the catastrophe came up. It must have been divine intervention.
I pulled up the line they sent me as fast as I could, climbed scary-fast out to grab the dangling end still attached to the limb, and quickly tied a square knot. The exact moment I yanked the second layer of the square knot tight, the last wood fibers holding onto the limb popped, AWAY went the branch. I grabbed the unguided lowering line, set it over the stub and burned hell out of my hand trying to hold the line.
Eventually the groundmen kicked in, caught the majority of the load on the line, and we were fine. The limb lightly swept the gutters of the second floor, missed the glass porch, and I finished the job without further complications. Except for the 3/4" wide rope burn running up the middle of my left palm from the heel of my hand to the tip of my thumb and first finger.
I was so relieved to save that branch, that I didn't care one little bit about the burn on my hand. I can't imagine how unhappy the customer would have been if I shattered the glass while charging him to remove the risk to his glass porch.
I still suffer from anxiety every time I tell this story. Deep sigh...