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skycat 0
Quote
"Some idiot" would have heard all this if he attend my lecture on re-lining during the PIA Symposium.
No offence, but not everyone can afford to take time off from work or pay to go to PIA every year that it happens.
![[:/]](/uploads/emoticons/dry.png "[:/]"){kind=small}
Fly it like you stole it!
Quote
The story seems incomplete.
Did the damage occur on opening? If so, how hard was the opening? If so, where did the lower brake line recieve damage if the brakes were stowed? If they were stowed, were they stowed properly?
Ok, let's see if I can clarify. "Lower" brake line was a bad way for me to phrase that. What I meant to say was at the end of the finger trapped portion of the line above the cat's eye you set the brakes with.
Jumper reported that the opening was fairly tame until the very end where it spun him hard. Given that this was an elliptical with the equivalent of a brake fire, that sounds about normal to me. Jumper said he began to scan the canopy to see what was wrong. He spotted the line trailing behind the canopy. Not feeling comfortable with rear risering the canopy, he then cut away. When the canopy was recovered, both toggles were still stowed with the brakes set correctly. In regards to the damaged suspension line, the break in the control line was not on the same level as the damage to the suspension lie but 4-5 inches further up, past the end of the riser.
When asked about hard openings, the jumper reported that the second jump on the canopy had a brutal opening but had had great openings since then. Witnesses said on a couple of jumps that the canopy appeared to snivel for a protracted amount of time then suddenly slam open. The jumper reports that while the canopy does tend to go briskly through the final stage of inflation, it is not at all hard. Given that and the fact that his canopy is over 250 sf of new ZP, I'd guess that maybe what the witness thought was the sound of a swack was really just the sound of that much new fabric reaching full inflation. This is just based on my personal observatiosn that larger parachutes tend to be noisier, but I'll freely admit that I could be totally wrong on this one.
-Blind
"If you end up in an alligator's jaws, naked, you probably did something to deserve it."
Not certain if it has anything at all to do with it, but what was your deployment speed? Didn't you tell me you were wearing a computer on that jump?
Steve
Steve
"Science, logic and reason will fly you to the moon. Religion will fly you into buildings."
"Because figuring things out is always better than making shit up."
"Because figuring things out is always better than making shit up."
QuoteA couple of weeks back, we had a cutaway after a brand new canopy blew a lower brake line on it's eigth jump. While doing an inspection of the canopy afterwards, I found one of the rear suspension lines severely frayed (about two thirds of the filaments in the line were broken) just above the bartack above the link. Ordinarily I'd suspect that whoever bartacked the line damaged it, but I noticed that there was about a 3/4 inch tear in the slider bumper in the same area. I know that the bumpers were new and had only been on the canopy for five jumps. Since the canopy had been jumped three times without bumpers, I examined the slider groments but found no nicks, so the damage doesn't come from there.
So basically I am looking at three possible scenarios in regards to the bumpers:
1. Rubbing against the bumper led to line damage which in turn led to the damage to the bumper.
2. The line was damaged by somethign else and the damage to the bumper is the result of the damaged line.
3. The bumper had a natural weak spot or took damage from something unrelated to the damaged line.
Which do you think is the most likely scenario?
Oh, and in regards to the brake line, cause of failure there seems to be some idiot melting the end of the line before finger trapping it.
-Blind
See if I have this right. The brake line broke above the cats eye and a suspention line broke about 4 ot 5 inches above the connectors.
If the brake line gave it up first that side of the canopy would have inflated first and right f*@king now. The lines on the side would have been coming off the riser and sharp angle away from the center and sliced in to the slider bumber, tearing it and damaging the other line. Was the broken suspention line an A/B line?
This is a guess sort of, but without seeing the canopy it my best guess.
Sparky
My idea of a fair fight is clubbing baby seals
riggerrob 643
My guess is that buddy had a tension knot in a line. When opening shock hit the tension knot tightened up and broke.
Remember that most types of knots weaken lines.
Finger-trapping is one of the few methods that maintain the full strength of the original line.
Remember that most types of knots weaken lines.
Finger-trapping is one of the few methods that maintain the full strength of the original line.
Thw slider bumper needs to be moved up about 1/8 inch up off the risers. This allows the top of the bumper to flex with the lines and reduces the chance of line wear. In other words when assembling the canopy on the risers DO NOT pull the slider bumper down over the links and part of the risers. Leave a little of the link showing at the bottom where it connects on to the risers. Thanks to Scott Miller from PD bringing this up at the main canopy inspection and packing seminar at PIA
Hope this helps.
Chris
Hope this helps.
Chris
Ok, I've had time to edit a picture down to a size I can post here. This photo was taken before I realized that there was a second line damged so it does not show it well. I've used arrows to highlight the point of damage on the second line and bumper. If you look close you can see where the damaged line seems to narrow down, this is where the broken filaments are.
Also, since I had someone PM me asking. The trouble did happen to me, and this is not a troll attempt. I posted it in third person to avoid people thinking I was making accusations against the canopy company before they have had a chance to respond.
As for the possibility of a tension knot, I do not think it was one. I am very anal retentive about my brakelines and every pack job I do involves two trips down the line, the first of which is to make sure the brakelines are not twisted. Gvien that the brakeline runs through my fingers twice, I feel that I would have felt a knot even if I didn't see one.
-Blind
Also, since I had someone PM me asking. The trouble did happen to me, and this is not a troll attempt. I posted it in third person to avoid people thinking I was making accusations against the canopy company before they have had a chance to respond.
As for the possibility of a tension knot, I do not think it was one. I am very anal retentive about my brakelines and every pack job I do involves two trips down the line, the first of which is to make sure the brakelines are not twisted. Gvien that the brakeline runs through my fingers twice, I feel that I would have felt a knot even if I didn't see one.
-Blind
"If you end up in an alligator's jaws, naked, you probably did something to deserve it."
hookitt 1
It appears the slider must come down and trap the brakeline between the slider grommet and the slider bumper.
This is a job for Slinks!!
This is a job for Slinks!!
My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto
Avion 0
QuoteOh, and in regards to the brake line, cause of failure there seems to be some idiot melting the end of the line before finger trapping it.
-Blind
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
That is the normal method if you use stainless steel finger-trapping fids. However "some idiot" forgot the last step which involves cutting off the hard end at a shallow angle. The shallower the angle, the smoother the transition at the end of the inserted line and the less likely the outer line will break.
"Some idiot" would have heard all this if he attend my lecture on re-lining during the PIA Symposium.
Indeed,
BTW:
What do you think of the method where the newly finger trapped end is pulled back through the coaxial section instead of using a bartack to lock it?
QuoteIt appears the slider must come down and trap the brakeline between the slider grommet and the slider bumper.
Wouldn't that result is a failure from friction? The ends of the break do not feel melted, only the finger trapped core just below where the break occured.
-Blind
"If you end up in an alligator's jaws, naked, you probably did something to deserve it."
riggerrob 643
QuoteQuoteIt appears the slider must come down and trap the brakeline between the slider grommet and the slider bumper.
Wouldn't that result is a failure from friction? The ends of the break do not feel melted, only the finger trapped core just below where the break occured.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
No, that would be a failure by whacking.
Sounds to me more like the original poster's line failed because it got whacked between two pieces of steel: a slider grommet and a Maillon Rapide.
Next time you get bored, try this parlor trick:
Tighten a piece of suspension line across an anvil, and whack it with a hammer. Even the smoothest hammer will cut your line and the tighter the line, the easier it is to cut.
Designer 0
This "Should" never happen.If the line was damaged in bar tacking,it is standard procedure to replace that section of line!period.It is also possible that when cutting the bumpers proper care might not have been taken to do it correctly.This is why parachute manufacturers have "So Many" Inspections.But even then,we are human.This should have been caught in final inspection!If in fact a mistake was made in production?Other possibilities exist where this could have happen in testing also.So,Nobody is out to burn anyone ok?I don't even understand burning a brake line.Yikes!!!!!!!
Did the damage occur on opening? If so, how hard was the opening? If so, where did the lower brake line recieve damage if the brakes were stowed? If they were stowed, were they stowed properly?
If the damage did not occur on opening, when was it discovered? Right on brake release or after?
As far as the bumper, it's not uncommon for a hard opening (I'm guessing that it was) to cause a slider to crack a bumper.
The frayed line is another story. If there was a defect in the line to begin with, again, a hard opening could finish the job.
I don't see any way a bumper could damage the line.
Considering thier proximity to each other, is there anyting in the main pack tray that could have caused the damage? Look at where the link would lie when the riser is in place, and see whats in that area. Is it anywhere near the d-bag? Is there anything on the d-bag grommets? A burr, or poorly seated edge?
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