All the flight parks that I am aware of are quite aware of this. They tell their pilots that the point of the weak link is save the glider from overload and that they should not rely on the weaklink to save them.
For whomever asked about the function of a weak link, it is to release the glider and plane from each other when the tow forces become greater than desirable -- whether that is due to a lockout or a malfunction of equipment or whatever. This can save a glider, a tow pilot, or more often, a hang glider pilot who does not get off of tow when he or she gets too far out of whack.
Is that how it works? Is that what it says on the written test?
Would you like to propose otherwise?
Yes, in fact, this *is* how it works.
Lisa Colletti - 2012/06
Higher Education
We want our weak links to break as early as possible in lockout situations, but be strong and reliable enough to avoid frequent weak link breaks from turbulence.
Towing Aloft - 1998/01
Dennis Pagen and Bill Bryden
Fortunately, we have good defenses against lockouts. These defenses include limiting the tow forces by using weak links and pressure gauges...
...
Weak links very clearly will provide protection from excessive angles of attack, high bank turns and the like for this form of towing.
...
A weak link is required that will not break needlessly in response to moderate thermals, or pilot inputs, yet will break at a low enough point to avoid disaster or excessive pilot panic.
...
Of course, your weak link should break before the lockout becomes too severe, but that assumes a properly applied weak link.
Even if they don't say that pilots can rely on weak links to save them, they certainly do think the job of the weak link is more than glider overload protection. Otherwise, they'd be using stronger stuff (as in the sailplane world).
When tension is lost, angle of attack will increase. If the angle of attack is already high when this happens, it can cause a stall. People have died because of this. This is reason enough not to use weak weak links. The FAA specifies a minimum legal limit on breaking strengths for a reason.
Does anyone know what size Xtralight Zack was flying?
Mark Frutiger - 2013/02/08 19:12:21 UTC
Zack hit the lift a few seconds after I did... I was still in the thermal when I caught sight of Zack again.
If I'm following Mark, the thermal took several seconds to traverse. That doesn't sound like a dust devil.
Oh, make it a dust devil. We don't wanna upset all the pro toads with the idea that they can be one Davis Link away from death flying into nothing more than a strong fat thermal.
Marc Fink - 2013/02/09 14:52:32 UTC
I've done some protows on low to intermediate performing gliders (not advisable in general) in a similar out-of-synch transition where once the line of pull got to a certain angle I was basically in a vertical lock-out and there wasn't anything I could do to prevent climbing at an accelerated rate of climb and increasing AOA. Very hard to do a real bar pull--in instead of what becomes essentially a push-up off the basetube.
I do think this may have been a contributing factor. He would have had more pull-in ability towing two (three) point.
Don't tell him that. We could really use him as a data generator.
I was on the phone with Chad May yesterday afternoon and he wanted me to send you his contact info - which I'm doing via e-mail - so's he could discuss with you using Wayback Machine to find out how close to Zack Marzec's impact and on which side it was that USHGA suddenly deleted all references to weak links and other towing equipment from the AT SOPs.
Did you ever experience such a wrap up yourself? I expect not, if you kept on using poly behind a DF.
Not a single time Billo.
So therefore it's not an issue that you have to worry about. It can only happen in the SOUTHERN Hemisphere.
I would bet 99% of our tows were with the COM or Skyting rig created by SkyGod Bill Bryden.
- Which has anything to do with the issue Billo brought up how?
- So you assholes really were stupid enough to put that Hewett garbage up behind a Dragonfly. In fucking credible.
- Yeah, Bill Bryden - a real SkyGod.
- So where are the authors of the excellent book, Towing Aloft, by Dennis Pagen and Bill Bryden now? How come they're not explaining to us why all the wonderful protections they claim a properly applied weak link will afford weren't? How come they're not explaining why we got the precise opposite results.
I think Davis was protowing when he flew his ATOS out of our flight park in Ottawa KS to somewhere in Iowa for a 189 mile record.
Awesome. What the fuck does that have to do with anything?
I think NME has it down pretty well.
Of course you do.
You my friend get a free tow on me if we ever tow together!
Great to see the way the battle lines are forming on this one. Pretty much exactly what one would predict.
And I just love the way in this sport that stupidity gets rewarded to the exact same degree that intelligence is always punished.
...but now do 200. The gliders have all gotten gotten 54 percent stronger - the new ones and all the stuff that's been around since before last summer that's been notified. Go any higher than 200 and were gonna start bending things - especially the older gliders that haven't been informed of the change.
2) The breaking strength of the weaklink on the tug (it must be less than that unless the tug pilot agrees).
FUCK THE TUG, FUCK ITS DRIVER, AND FUCK YOU.
We pay those goddam useless brain dead pieces of shit to pull us into the air safely and legally. It's about time we take back control of this sport from scum like you and your tug driver buddies.
And please explain to me how it's any skin off HIS nose if WE end up with the rope?
3) Unlike with a sailplane it must break if the pilot and glider plow into the ground.
In sailplaning they use RELEASES to RELEASE the glider from tow when they want or need to. They don't use the cheap total crap that some douchebag tug driver like Bobby Fucking-Genius Bailey slapped together and ordered us to use - to the exclusion of anything that doesn't stink on ice.
So tell me how many Gs we should be using to guarantee that it will blow if the pilot and glider plow into the ground and minimize injuries and damage.
Davis Straub - 2009/01/03 20:50:24 UTC
Forbes Airport, New South Wales
Steve Elliot came off the cart crooked and things went from bad to worse as he augured in. He was helicoptered to Orange and eventually to Sydney where the prognosis is not good. I'll update as I find out more.
...Davis Link didn't do the job well enough to keep him alive and why HGFA didn't mandate lighter ones after that incident?
I am more than happy to have a stronger weaklink and often fly with the string used for weaklinks used at Wallaby Ranch for tandem flights (orange string - 200 lbs). We used these with Russell Brown's (tug owner and pilot) approval at Zapata after we kept breaking weaklink in light conditions in morning flights.
Is there any shit that comes out of that rotten dump...
Here is the requirement from the 2007 Worlds local rules (which I wrote) for weaklinks:
Pilots must use weaklinks provided by the meet organizers and in a manner approved by the meet organizers. All weaklinks will be checked and use of inappropriate weaklinks will require the pilot to go to the end of the launch line to change the weaklink.
Weaklinks will consist of a single loop of Cortland 130 lb Greenspot braided Dacron Tolling line and should be placed at one end of a shoulder bridle.
At the 2008 Forbes Flatlands Greenspot for the first time was used as the standard weaklink material (thanks in large part to the efforts of Bobby Bailey). We applaud these efforts to improve the safety of aerotowing by using a better weaklink material.
So happy that you dictated that everybody had to use it no matter how often and/or badly it was crashing them, punish anybody who defied you, and declared that "WE" applaud Bobby Fucking-Genius Bailey - instead of putting the motherfuckers head on a pike where it belongs?
Are we gonna hafta applaud Russell Fucking Brown now? Or doesn't the 200 have a long enough track record to be declared a proven system that works?
If this sport ever gets its shit together enough to start putting gliders up at the middle of the FAA legal/safety range are we gonna applaud Tad for HIS efforts to improve the safety of aerotowing by advocating, developing, and providing weak link ratings and technology and battling all you goddam backstabbing motherfuckers for years to get it into circulation?
Tug pilots want their weaklink to break if the rope gets caught on some barbed wire.
Is there ANYTHING that those pigfuckers want that they don't get?
So what's the G rating that's guarantees that a weak link will blow if the towline snags. Or do pounds?
Is the triple strand the assholes are using now guaranteed to do the trick?
Is groundspeed an issue? If someone's coming in with a strong headwind and snags the towline in some springy tree branches will the triple strand guarantee the tug's survival.
If the idiot fucking tug drivers are so goddam worried about the towline popping off if it snags then...
William Olive - 2013/02/20 06:42:07 UTC
One thing though, new poly rope has a penchant to twist and can quickly wrap up a DF release, rendering it impossible to release and even if the WL does fail, the top rope wont pass through the ring, which is why Bill Moyes uses expensive Spectra rope for his towlines.
Towing Aloft - 1998/01
I witnessed a tug pilot descend low over trees. His towline hit the trees and caught. His weak link broke but the bridle whipped around the towline and held it fast. The pilot was saved by the fact that the towline broke!
...why do ALL OF THEM configure such that there's a real strong possibility of the weak link they've elected to use being taken completely out of the equation?
If you want them to have a stronger weaklink you'll have to talk with them first.
How 'bout we just talk to the FAA instead? Get them to understand that aviation isn't supposed to be conducted on the basis of idiot opinions?
They need to be safe and comfortable...
There is no weak link capable of getting a glider airborne that gives a rat's ass about anyone's safety or comfort at either end of the string.
And anybody who believes for a nanosecond otherwise...
Sheryl didn't take all that long to get to the heart of the matter on a much milder version of the same deal.
So are you lying because you're smart enough to appreciate what's gonna happen to all you goddam 130 pound Greenspot Nazis if you admit the obvious? Or are you actually that incredibly stupid?
The breaking strength of the weaklink on the tug (it must be less than that unless the tug pilot agrees).
From the USHPA aerotow SOPs, it sounds like it's the other way around. They define appropriate weak links for gliders, then state:
The weak link used at the tow plane end of the towline must be stronger, but not more than 25% stronger, than the strength of the weak link used at the glider end of the towline.
Not any more, they don't.
Unlike with a sailplane it must break if the pilot and glider plow into the ground.
I rely on my release for this.
Yeah, but you use a release from Joe Street and...
Davis is very happy with the way Quest Air (Bobby Bailey designed) does it now.
Tug pilots want their weaklink to break if the rope gets caught on some barbed wire.
And I want my Hewett Bridle to auto-correct my glider if I get rolled off to the side. But that ain't never gonna happen neither.
At our local club we use a 600 lb weak link on the tug end. It's broken after the rope snagged fences without issue.
And a 200 pound weak link - under the right circumstances - could drag the tug down and kill kill it. So let's go with 180 just to be on the safe side.
Or - here's another thought...
Try not dragging the fucking towline over barbed wire. I'll bet that's something I'd be able to not do in the course of a typical day of towing.
But, given the caliber of people we've got to fly these things...
I can't see how the weaklink has anything to do with this accident.
You don't think there's even a remote possibility that Zack could have survived had his weak link held?
At the 2008 Forbes Flatlands Greenspot for the first time was used as the standard weaklink material (thanks in large part to the efforts of Bobby Bailey). We applaud these efforts to improve the safety of aerotowing by using a better weaklink material.
...we've all applauded Bobby Fucking-Genius Bailey's efforts to improve the safety of aerotowing by using a better weak link material. 'Cause then everybody would realize we're all total morons.
...would like to know what, if anything, we can do to prevent something like this from happening again.
- Suspend the Quest Air operation and fine them a hundred thousand dollars for violating the crap out of FAA aerotow regulations on the vast majority of tows to get their attention.
- Mandate a 1.4 G minimum for hang gliders.
- Fix the goddam Dragonflies to the point at which they're capable of doing their goddam jobs.
- Pull the ticket of any idiot tug driver who insists on using a weak link compatible with his comfort level rather than compliant with FAA aerotowing regulations.
There are three ways to solve such a problem:
1. Release at the very begining. As for me, it's the most wise decision.
Yes. That WOULD BE consistent with...
Quest Air
ALWAYS RELEASE THE TOWLINE before there is a problem.
Quest's approach.
2. Try to pull on the bar to reduce a climb rate.
I like that one - 'cause when you're flying one point TRYING is about all you can do.
"Brutal force" method.
I think the "grow longer arms" method would work a lot better. An anorexic little girl flying two point is gonna be a lot more effective in getting the nose down than Arnold Schwarzenegger is flying one.
From time to time it works.
No it doesn't. There's no glider on the planet that requires brute force to get the bar all the way back. And you can't push on it any harder than it's pushing back on you. And when you're flying one point it's really easy to push the bar all the way back 'cause when it's all the way back it's nowhere near all the way back.
If not then do the p.1.
It's too late for that. And, besides, at this point that's a really bad option.
3. Wait for weak link gets broken. The most unclever method.
Bull shit.
Towing Aloft - 1998/01
A weak link is the focal point of a safe towing system.
The weak link is the focal point of a safe towing system. It's an incredibly clever device. It has to be to be able to meet all of our expectations.
I'm not talking in the context of Zach's case.
No shit.
I'm just trying to answer the quoted question.
The quoted question WAS about Zack's case. And in order to be actual PILOTS we need to look at and be prepared as best as possible for the worst case scenario - ALL THE TIME. If we're just looking at what we can get away with just about all of the time we're just dice rollers.
Regarding Zach...
I don't know what force made him to allow to reach a very high AoA.
What? You've never been blasted by powerful lift?
And I don't know why he did not do something to escape from this situation.
He was towing off his shoulders so THERE WAS NOTHING MORE HE COULD'VE DONE.
I'm really sorry but one more death makes us to think about the cause again.
It doesn't make me think. I did my homework so there was nothing for me to learn from this one.
The effect we know. Unfortunately. Again.
Yes. Exactly. AGAIN. This death was NOT UNPRECEDENTED.
One thing I know exactly: stopped glider with high AoA is a 100% candidate to thumble.
Yep.
So we have to avoid getting into such situations.
And at exactly what point did the glider stop moving forward and what could we have done differently to ensure that it kept moving forward?
Other thing I know: a lot of pilots are afraid to take away one hand form a bar while the bar pressure is scary high.
Yeah. There's a damned good reason for that.
They think the glider immediately will do something bad.
Now why...
Dennis Pagen - 2005/01
The glider instantly whipped to the side in a wingover maneuver.
So you pull whatever release you have but the one hand still on the basetube isn't enough to hold the nose down and you pop up and over into an unplanned semi-loop. Been there, done that... at maybe 200 feet agl.
A recurring delusion.
At least one second we have. It's more than enough to make a release and get back the hand on the bar.
BULLSHIT. You're telling yourself that because you don't want to believe that you're doing something stupid and dangerous by using cheap shit for a release. Get something that doesn't stink on ice. It's not that hard or expensive and you'll feel a lot better actually BEING safe than trying to CONVINCE YOURSELF you're being safe.
But this DOESN'T HAVE SHIT to do with Zack Marzec. At NO POINT did he attempt or have any desire to pop himself off tow. He desperately wanted to do the opposite. But he had taken that option off the table for himself before he got on the cart.
Other thing I know: a lot of pilots are afraid to take away one hand form a bar while the bar pressure is scary high. They think the glider immediately will do something bad. It's a delusion.
Imagine if you will, just coming off the cart and center punching a thermal which takes you instantly straight up while the tug is still on the ground. Know what happens? VERY high towline forces and an over-the-top lockout. You'll have both hands on the basetube pulling it well past your knees but the glider doesn't come down and still the weaklink doesn't break (.8G). So you pull whatever release you have but the one hand still on the basetube isn't enough to hold the nose down and you pop up and over into an unplanned semi-loop. Been there, done that... at maybe 200 feet agl.
Davis Straub - 2013/02/09 17:37:44 UTC
I rely on my release for this.
A mouth release would be the best for that, but a barrel release will not do you much good in this situation. You won't get to it in time.
No shit, asshole. Which is another way of saying that what you...
Davis Straub - 2011/07/30 19:51:54 UTC
I'm very happy with the way Quest Air (Bobby Bailey designed) does it now.
...and your douchebag buddies perpetrate on the public is dangerous junk.
Davis Straub - 2013/02/09 17:40:07 UTC
From the USHPA aerotow SOPs, it sounds like it's the other way around.
Sorry for any confusion.
Since when did you start being sorry for confusion? The only way you manage to survive is by keeping as many people as you possibly can as confused as you possibly can. And a big part of the way you accomplish that is to silence anybody who starts making a bit of sense.
Yes, the weaklink at the tug end is stronger than the weaklink at the pilot end.
Yeah, as long as the weak link at the pilot end is one of the illegally light Davis Links you assholes force everybody to use. But anybody who tries to get up into the middle of the safety range is fucked.
But if the pilot uses a stronger weaklink then the tug pilot needs to make their weaklink stronger and they may not be happy to do so.
Yeah? Well FUCK THEM. Hell, name one of them who can even translate his strands of 130 pound Greenspot to pounds of towline tension. Have them find some job they're able to do competently and safely - preferably something involving a broom. Sailplane pilots don't hafta put up with this bullshit - why should we?
Davis Straub - 2013/02/09 17:42:16 UTC
At our local club we use a 600 lb weak link on the tug end. It's broken after the rope snagged fences without issue.
What club would that be?
Something better than all those assholes in Florida and their stupid clones.
What makes for a 600 pound weak link?
Heavier string.
I believe that the tugs I am familiar with use three strands of 130 pound on a V-bridle.
Wanna express that in pounds of towline tension? Just kidding.
Davis Straub - 2013/02/09 17:45:21 UTC
You don't think there's even a remote possibility that Zack could have survived had his weak link held?
I have no idea of the circumstances he faced.
You're right Davis. This one's a COMPLETE MYSTERY and it's probable that nobody will ever REALLY be able to understand what happened here. Will just hafta keep flying pro toads with Davis Links and hope that when the next guy gets the same results he'll have had a camera running and a GPS receiver recording. And I'm hoping that'll happen early this season to you, Rooney, or Adam at Ridgely during the ECC.
Zack C - 2013/02/09 18:12:30 UTC
A mouth release would be the best for that, but a barrel release will not do you much good in this situation. You won't get to it in time.
I agree, which is in part why I don't use barrels.
If I conceivably couldn't get to my release in time in that situation, I conceivably wouldn't make it in time in other situations. Not only that, but taking a hand off the controls while fighting a lockout is, in my opinion, a bad idea.
Yeah, well, ya know, that's just like, uh, your OPINION, man.
What club would that be?
Hang Glide Texas (Columbus).
How long a track record do they have?
What makes for a 600 pound weak link?
Four strands of 205 leech line, in-line with the tow rope (we use a trike).
I believe that the tugs I am familiar with use three strands of 130 pound on a V-bridle.
The standard for Dragonflys. Anything stronger and the tow mast could break before the weak link (by design).
Isn't it great how well the search function is working at the Oz Report server?
Yeah Davis, super. And this way you can limit the number of people who can see what's going on and realize what stupid, incompetent, duplicitous, lying assholes you and your friends are.
I was on the phone with Chad May yesterday afternoon and he wanted me to send you his contact info - which I'm doing via e-mail - so's he could discuss with you using Wayback Machine to find out how close to Zack Marzec's impact and on which side it was that USHGA suddenly deleted all references to weak links and other towing equipment from the AT SOPs.
I am 100% sure I checked the SOPs on USHPA's site at least one week after Zack's death and it was still the old (June 2012) version. I consulted them during the Oz Report discussion. They are quoted in this post on 2/9: http://ozreport.com/forum/viewtopic.php?p=117866#117866
I got that quote directly from USHPA's website at the time I wrote the post.
I first noticed that they were different on the same day I reported the change (2/14). I was consulting them again as part of the same discussion, though I don't remember the exact reason. The change was recent as Google was still showing the text of the previous version in search rankings. The URL of the document (PDF) didn't change (just its content). As Google still had the old version cached, I pulled the cached version and uploaded it to Kite Strings in the previously referenced post.
I immediately suspected they were modified in response to the incident and/or the subsequent discussion. However, I compared the beginnings of the documents and noticed there were other changes. I haven't gone through the two versions to identify every change as I haven't had time (file comparison software would be the easiest way to do this, but you might have to convert the documents to text first), but I might do this eventually.
Anyway...I'll direct Chad to this post.
Tad Eareckson wrote:How long a track record do they [Hang Glide Texas] have?
They've been operating since 2001. Mostly just on weekends though. As far as I know we've never had any towing-related incident (certainly not since I moved here), although we came close last year in the event described here. Almost everyone uses 130 lb Greenspot, although I think Gregg uses 200 lb. Other than the tug weak link, we operate pretty much the same way as the flight parks, except 'funky shit' isn't prohibited (we've got a couple of home built releases).
Thanks much for that delightful information on the timing. Looks like we have them. Really amazing how the dynamics of our national organization work such that every time an easily preventable fatality occurs the relevant standards are degraded and/or eliminated to more easily facilitate reruns.
And at this point I REALLY hope they get rewarded for their efforts. I hope they bring Donnell in for consultation. According to his Sacred Skyting Criteria the reason Zack Marzec died was because his weak link was too heavy.
A properly designed weak link must be strong enough to permit a good rate of climb without breaking, and it must be weak enough to break before the glider gets out of control, stalls, or collapses. Since our glider flies level with a 50 pound pull, climbs at about 500 fpm with a 130 pound pull, and retains sufficient control to prevent stalling if a weak link breaks at 200 pounds pull, we selected that value. Of course, a pilot could deliberately produce a stalled break at 200 lbs, just as he can stall a glider in free flight. But if he is trying to limit his climb rate and the forces exceed the break limit, the glider simply drops its nose to the free flight attitude and continues flying. If the weak link breaks (or should the towline break) at less than the 200 pound value, the effect is even less dramatic and controlled flight is still present.
Drop our pro toad bridle end weak links thirty pounds, problem solved. Of course we'll need to find something manufactured to the fine tolerances acceptable to Rooney, so that may be something of a hitch. But if/when we clear that hurdle he'll allow us to use it on our two point bridles as well.
And hopefully we'll be able to get the fatality rate up to about five or ten a season. (What an idiot I was to have entered this campaign with the motivation of reducing it.) And then maybe the next time Davis runs a poll for his Jim Gaar caliber douchebags 48 percent of his respondents won't be quite so positive they're using the "correct" strength - hopefully because they will no longer be in a position to respond to anything.
Sorry you went to the trouble of answering my (rhetorical) question about your club's "track record". As I'm sure you know I count every flight that goes up with a standard aerotow weak link as a kill - whether or not they get away with it.
No one can say if Zack would have survived had he stayed on the line.
I'll give it a shot...
If he had stayed on the line for another three seconds or so he'd have been able to get the glider stabilized and he'd have been fine.
But if I was in his situation, I'm pretty sure I wouldn't have wanted the weak link to break.
Davis Straub - 2013/02/09 20:29:52 UTC
Each line of the bridle would be carrying 135 pounds at 1 G force.
Depends on how you define '1 G'. The FAA and USHPA specify weak link limits as a proportion of the maximum certified operating weight of the glider, not its actual operating weight. For the smallest Xtralight the maximum weight is about 311 lbs, so a line tension equal to that would give 155 lbs per shoulder. A shoulder weak link that breaks at 130 lbs (allowing 260 lbs of towline tension) will break at 0.8 times that weight, which is at the bottom of the legal range (0.8 to 2.0).
The safest part of the range, of course. The way it works is that beginners are put up at 0.8 and as they learn to eat up less and less altitude in their stall recovery drills they're permitted heavier and heavier weak links up to the point at which the glider's at risk of being bent. See the FAA's "Glider Flying Handbook" for more detailed information on this.
A loop of 130 lb Cortland Greenspot breaks at about, well see here:
One of whose names must not be mentioned lest the post be deleted.
...and gotten around 130 lbs (200 lbs for four strands). Others have reported similar results (120 lbs in Towing Aloft, for example), but I know less about their methods. These results are consistent with the ones you reported but more precise.
I stick to the middle of the FAA's mandated range. USHPA SOPs recommend a weak link value equal to the flying weight of the glider when placed at the end of a bridle. In both cases that gives me a weak link value of about 260 lbs, which is what I use. More on the numbers here:
I fortunately don't have to worry about the tug end at our local operation as my weak link breaking tension is still well below the tug's. Elsewhere it would be stronger than the tug's, but it's not like that's unusual (anyone using four strands of 130, which includes most tandems, is stronger).
Isn't it great how well the search function is working at the Oz Report server?
Google works great. Just wish Google could still be used to search the forum.
Me too. I'd like as many people as possible to be able to watch the meltdown in real time.
