The FAA requires that the weak link breaks at line tensions between 0.8 and 2.0 times the maximum certified operating weight (MCOW) of the glider, which will be the glider's weight plus its maximum hook-in weight. The MCOW of my S2 155 is 309 lbs. This means that legal weak links for this glider would allow towline tensions between 247.2 and 618 lbs. At the end of a two point (AKA three point...) V bridle with a 60 degree apex angle, the weak link will see 0.575 times the line tension, which would mean a weak link breaking strength between 142 and 355 lbs, with 250 being in the middle. This is about the breaking strength of a loop of 205 leech line (commonly used in surface towing) as well as the 250 lb stuff at TowMeUp.com (what I'm currently using).
A lot of people assume a loop of the ubiquitous 130 lb Greenspot will break at 260 lbs. In reality it will break close to 130 lbs (the TowMeUp link above will confirm this) and is thus either illegal or barely legal for most gliders.
Like Zack Marzec's Moyes Xtralite 147.
Make sure your release can handle whatever tension your weak link allows.
Just make sure it uses a bent pin so you can easily close it over a heavy rope.
Paul Hurless - 2012/08/14 15:34:23 UTC
You're confusing certified gliders (sailplanes) with hang gliders. The FAA doesn't give a hoot about what we use for weaklinks.
- Great job suppressing the news of our inclusion under sailplane regs eight years prior, USHGA.
- You didn't read Dr. Trisa Tilletti's "Higher Education" article in the magazine two and a half months ago? The one first informing us of the eight year old FAA regs and how 130 pound Greenspot has been keeping everyone in full compliance all this time?
Zack C - 2012/08/14 15:53:22 UTC
See the regs. They explicitly reference 'unpowered ultralight vehicles'. Also see Tracy and Lisa's article in the June edition of the magazine.
Paul Hurless - 2012/08/14 16:21:23 UTC
Our wings have recommended operating weights, but they are not certificated . As usual the feds did a poor job at trying to incorporate our wings into the mix of the regulations governing certificated aircraft.
"As usual"? So...
- In what other areas have they perpetrated dangerous blunders which are upping our crash, injury, fatality, rates?
- What the fuck have you, your Jack Show buddies, the Flight Park Mafia, and USHGA done to address these outrageous situations?
Zack C - 2012/08/14 17:30:55 UTC
Our wings have recommended operating weights...
They're not recommendations. From Wills's site:
The range of hook in weights given is the range for which the glider complies with the performance, stability, control and structural requirements of the HGMA Airworthiness Standards...
...but they are not certificated.
Not by the FAA, at least.
As usual the feds did a poor job at trying to incorporate our wings into the mix of the regulations governing certificated aircraft.
That may be true, but it's clear they intended the same regulations to apply to both sailplanes and hang gliders. Legality aside, it should also be clear why weak link breaks are common for hang gliders but virtually unheard of for sailplanes.
Paul Hurless - 2012/08/14 17:39:22 UTC
It is pretty clear from what I seen when I've aerotowed. Reusing weak links and pilot errors were the two most common causes.
So...
- Was Zack Marzec's weak link dangerously fuzzed out?
- Was he just crappy at aerotowing?
- Some combination of the two?
If any of that is the case how come none of the Quest/USHGA sleazebags - who are desperate to divert attention from the two ACTUAL issues - have made the slightest suggestions along these lines.
The good thing is that a weak link break is no big deal other than missing out on that tow. A weak link failing to break is a whole other problem.
Moron.
Personally, I prefer to fly off mountains and not have to deal with towing. It's so much simpler to just run off a launch.
...should stay the fuck out of discussions on towing.
Mike Lake - 2012/08/14 18:11:23 UTC
No big deal as long as you don't hit the ground, something I have witnessed on a few occasions.
Paul Hurless - 2012/08/14 18:13:13 UTC
That's true of any kind of launch. Failing to be ready to immediately land if a weak link breaks is a very basic pilot error.
Very basic pilot error:
Mike Lake - 2012/08/14 19:25:17 UTC
Pilot error?
Try the textbook...
"Pull in and the nose will gently drop, make a normal landing etc etc."
at 30' with one wing up a bit. Add a bit of a breeze if you're brave.
It doesn't matter how ready or good you are if you hit the ground first.
It is true all launches are a risk and the task is to do everything to minimise the risk.
A weak-link that might or might not break at critical launch time doesn't exactly help and is only a non event if you are not the one airlifted to hospital.
Zack C - 2012/08/14 20:23:17 UTC
I've tested lightly used weak links (a few flights on each) and found no variance in breaking strength compared to new ones. I've also had new ones break under normal conditions the first time they went up. (130 lb Greenspot used in all these cases.)
Anyway, what I was referring to is the fact that hang gliders use much lighter weak links (proportionally) than sailplanes.
The good thing is that a weak link break is no big deal other than missing out on that tow.
If that's the case, why does the FAA mandate a minimum breaking strength?
They don't understand that, while a catastrophic failure of tow tension in sailplaning is dangerous, in hang gliding it increases the safety of the towing operation and is never more serious than a mere inconvenience.
Losing the rope just after launch is as big a deal as an airplane's engine seizing just after takeoff. A sudden loss of power will cause the aircraft to stop climbing and start descending. This means an increase in angle of attack, which could potentially cause a stall.
Let's see what Mitch Shipley, Quest Tandem Aerotow Instructor and USHGA's Accident Reporting Committee Chairman, has to say on the issue...
...are only counted if they're heavier than 130 pound Greenspot. When somebody fatally locks out and slams in with his 130 pound Greenspot the incident just adds to its sterling track record.
The weaklinks that I have seen fail were from physical wear, not a lack of strength from reuse. If you're going to reuse one it needs to be inspected, not just hooked back up with taking a look at it.
Any why wouldn't a hang glider use a weaker weak link? With the exception of rigids we don't have the options available to sailplanes in the form of flight controls. No matter how out of shape they get, unless they are stalled, they can still have positive control of their craft. We, however, have to worry about things like lockouts. If they go too far we can quickly run out of options. Weak links should break when needed, having one not letting go when you are in bad shape is a bad thing.
I am curious about why some people fear low level weak link breaks...
Being aware of what can go wrong and knowing how to handle it during a critical phase of your flight is an important thing, I think. If you're ready for it when or if it happens it can be easily dealt with. It's not that difficult. It should pretty much be an automatic response.
As far as the FAA mandating what we should use, face it, they aren't really very knowledgeable of our type of flying. They just try to lump us in with sailplanes so they can say they have us covered.
And they've never done shit in the course of the better part of three decades in the way of enforcing any aerotowing safety standards, conditions, agreements, requirements, regulations so who really gives a flying fuck?
I can't cite any specific instances of incidents caused by a weak link failing to break, I don't keep a file of statistics. I would think that if you took a look at incidents where lockouts played a big role you would probably find some.
The truth is out there.
Zack C - 2012/08/15 14:31:43 UTC
Weak links should break when needed...
Which is when? You seem to think it's the job of the weak link to protect the pilot from lockouts, which is not the case...
Paul Hurless - 2012/08/15 15:44:16 UTC
My personal opinion is that ALL of the safety equipment I use is to protect me, not my glider, so I have to agree to disagree with anyone who says differently.
The purpose of safety equipment, such as a weak link, is to act as a backup not a preventer. It's not always going to save your bacon if you have let things go all sideways. Believing that a stronger weak link is somehow safer just doesn't make sense.
As with many changes in avaition, change is approached with a bit of skepticism. Rightfully so. There's something to be said for "tried and true" methods... by strapping on somehting new, you become a test pilot. The unknown and unforseen become your greatest risk factors. It's up to each of us to individually asses the risks/rewards for ourselves.
...or the fact that changing one step of it could prevent it. I'm very familiar with that aspect of aviation, but you're putting us back to what I said about safety equipment being a backup not a preventer.
No matter what we do to improve safety equipment we will always have the same weak link in the chain, the pilot. If the pilot in command fails to operate his craft in the proper manner or fails to recognise when things have gone wrong then bad things are going to happen. You can' t reasonably expect to rely on a piece of equipment to prevent it since pilots are always going to find ways to outsmart themselves. It's human nature. No matter if you want to use strong weak links or weak ones, blaiming a piece of equipment for causing injuries or worse when it was used outside it's normal operating range is just useless finger pointing.
Paul Hurless - 2012/08/15 15:47:36 UTC
Releases are an entirely different subject. A good release is only good if used when needed. If the pilot waits to long, then the effectivity and safety available to the pilot can be missed completely, but that's not the fault of the equipment.
Anybody who is truly a good pilot, in any form of aviation, knows that the knowledge, skills, and judgement you have in your head, learned from thorough instruction from a good instructor with a good curriculum, are the best pieces of equipment you can fly with. Good equipment is important, the best equipment is a well-trained brain.
...is.
Zack C - 2012/08/15 19:55:45 UTC
They're saying that the job of the weak link is to keep the glider from being overloaded - not to save the pilot if he fails to release...
Paul Hurless - 2012/08/15 20:13:11 UTC
As far as what those others say, remember that they have never been on your end or my end or anyone else's end of the tow rope, only their own....
Jim Gaar - 2012/08/15 20:18:56 UTC
You were doing great til this crept in Paul. Zack in no way comes across like Tad.
Still, you are both making valid points and that could save lives!
But... Paul's idiot "valid" points remained SOP and, consequently, five and a half months later...
Paul Hurless - 2012/08/15 20:36:30 UTC
I was actually referring to the way his posts are becoming longer and divided up into many quotes as well as sometimes seeming to cover the same thing over and over again.
And here we are, one dead tandem aerotow instructor later, seeming to cover the same thing over and over again.
Mike Lake - 2012/08/16 00:19:10 UTC
Wherever you put the blame and whatever a pilot should or shouldn't do the fact remains that on an otherwise ordinary (or at least manageable) tow pilots have been injured, killed and gliders bent because of weak-link failures...
Craig Hassan - 2012/08/16 11:15:57 UTC
My last weak link break was 2010 at the Mid West Comp. I've been using the same weak link since then.
Super, Craig. The last time anyone was killed on a Lockout Mountain Flight Park release was 2009/08/31 - and plenty of people have been surviving their numerous malfunctions in the four years since. So, obviously, there's not a serious problem.
So my suggestion is, don't break your weak link and it won't cause you any problems.
- So what was it you think that Zack Marzec did wrong to break his standard aerotow weak link and have the failure cause him some problems?
- So can I take it that you're not necessarily on board with Paul Hurless, Paul Tjaden, Davis Straub, Jim Rooney, Peter Birren that a weak link blow is physically incapable of causing anything more serious than a bit of inconvenience?
Craig Hassan - 2012/08/17 10:43:10 UTC
Stay focused, stay in position, and stay in control. This flying thing is easy when you do that.
So how come you've got four posts - plus one you deleted - in this thread and zero in any of the Zack Marzec discussions?
So my suggestion is, don't break your weak link and it won't cause you any problems.
Would you tell that to Jonny Durand, who (among others) broke at least one weak link at Big Spring?
Even a 'perfect pilot' will break a 5 lb weak link. So where's the cut off breaking strength above which all weak link breaks become pilot error? Keep in mind that the tension on a weak link will vary depending on bridle configuration, glider, pilot/glider weight, and tug climb rate, so be sure to factor those in the computation.
Huh?
If all weak link breaks are pilot error, perhaps you can point out the error here:
Would you tell that to Jonny Durand, who (among others) broke at least one weak link at Big Spring?
Yes
I "pro-tow" Sport 2 155, U2 160, and now a Climax 14. I've weighed between 195 and 230lbs over the past few years. I've towed behind The Dragon Fly (from 2 stroke to 4 stroke turbo, about 8 or 9 different ones.) Kolbs and a Challenger at Hang Glide Chicago, and a trike at our home field. I was towing behind the Challenger when I broke my last link. 4 minute tow to 900'
The white and green line that most places use is fine for the weight ranges I have been and the gliders I have flown behind the tugs that have provided my tows. I can't say much more for anyone else.
If all weak link breaks are pilot error, perhaps you can point out the error here...
Never said that they were pilot error. I just said don't break them and you won't have an issue.
Tom Noddy said "Bubbles will last forever if they don't break."
Heard him say that when I was about 7 or 8 and kind of liked it.
As far as the video.
Obviously an early morning tow. (Not much thermal activity yet I would guess) So the tow would have been a fairly smooth tow, or maybe there was some wind and mechanical turbulence. (The tuft on your nose wire doesn't seem to show much ground wind.)
I do see the tug move up a little, but not enough to warrant the large input you made. (Bar 18-20" forward, from abdomen to almost above your head.)
So since you asked for it, my opinion is YOU did cause the weak link to break. Don't be angry, you asked for my opinion and I gave it. I could very well be 100% wrong.
stupid pin bending, pro toad, 130 pound Greenspot clone?
Zack C - 2012/08/17 16:12:56 UTC
Never said that they were pilot error. I just said don't break them and you won't have an issue.
I'm afraid your point is lost on me, then. Did you have one, or was the statement meant purely in jest?
With Craig does it matter?
It was actually around 3:30 PM. Thermal and mechanical turbulence (it was ridge soarable). After the break the tug pilot commented (as a possible explanation) that conditions were rowdy.
The GoPro's wide angle distorts distances. I've found tug movements are greatly understated in shots like this. But what the tug is doing in the video, or whether the input was warranted, isn't important...what's important is if an input like this could ever be warranted in some set of circumstances.
So since you asked for it, my opinion is YOU did cause the weak link to break.
I agree. That's why that was the last time I flew with 130 lb line. Inputs like the one exhibited in the video are common in rowdy conditions. I no longer worry about being dumped because of them.
Where's the sport in that?
michael170 - 2012/08/17 17:01:40 UTC
Zack, let me see if I understand your logic.
You had a thing and it broke needlessly.
You didn't want the thing to break needlessly.
You replaced the thing with a stronger thing.
Now the thing doesn't break needlessly.
We engage in a sport that has risk and that is part of the attraction.
Kinsley Sykes - 2012/08/17 17:09:23 UTC
And now the thing might not break when you need it to...
Given the choice, I'd rather it break when I don't need it than not break when I do... but I really don't want to open this can of worms.. A weaklink break should be a non-event, if it's an event, I'd say the problem is with the pilot not the "thing"
An eminently qualified tandem pilot reported a random incident that we all could learn from
My response would be - "Thanks for letting us know that we have to be careful about how long our weaklinks are".
All the other crap you (ridgerodent) wrote is just noise.
Wasn't Zack Marzec also an eminently qualified tandem pilot who experienced a random incident that we all could learn from?
- If he had survived his thing breaking when he needed it to what do you think he'd have reported that we could all have learned from?
- Ya think Lauren would have ended up any less dead in the same circumstances? If:
-- so, how come her sole contribution to the public discussion has been:
I am posting the report my husband, Paul Tjaden, just wrote about Zach Marzec's death at Quest. It is a great tragedy to lose someone so young and vital. We are sick about it, and our hearts go out to his friends, family and loved ones.
-- not is there the slightest possibility that the bitch isn't all that fucking eminently qualified?
Mike Lake - 2012/08/17 19:08:45 UTC
You had a thing and it broke needlessly.
You didn't want the thing to break needlessly.
You replaced the thing with a stronger thing.
Now the thing doesn't break needlessly.
Concise, logical and absolutely the correct thing to do.
However, if you had added ...
"And remove the pilot's release at the same time"
frankly, that would have been sh**.
...
But the gentleman quoted above didn't add that line so a pilot at the top end with his beefed up weak-link AND a release is going to suffer ... what?
Paul Edwards - 2012/08/17 19:22:25 UTC
Can someone help 'dumb it down' for me? I cannot exactly follow the debate... too many words and not always on the point.
Sure, Paul...
- The purpose of a weak link...
Tost Flugzeuggerätebau
Weak links protect your aircraft against overloading.
...is to protect your aircraft against overloading.
If you're stupid enough to dumb it down in order to try to use it as an emergency release the chances of it doing that are so close to zero that the difference isn't worth mentioning and the chances of it crashing you go through the ceiling. In extreme low level thermal conditions...
Donnell Hewett - 1980/12
Now I've heard the argument that "Weak links always break at the worst possible time, when the glider is climbing hard in a near stall situation," and that "More people have been injured because of a weak link than saved by one."
...you've pretty much signed your own death warrant.
- A release is supposed to allow the PILOT to stay on or blow tow at his discretion. But if you're stupid enough to configure it so you have no possibility of actuating it while you're controlling the glider...
...you can count on getting your face rearranged...
...in fairly minor situations and your fuckin' neck broken...
The Herald on Sunday - 2009/01/10
Hurt hang glider pilot joked bravely with friends after a crash landing, unaware that his injuries were fatal.
But he began losing consciousness as he awaited the arrival of paramedics.
Aucklander Stephen Elliot, 48, was taking part in the Forbes Flatland Hang Gliding Championship in Sydney last Saturday when he landed badly.
Elliot shattered four bones in his neck and damaged several blood vessels that supplied blood to the brain. He was flown to the Royal North Shore Hospital in Sydney and put into an induced coma but died on Monday.
...in circumstances just a bit more interesting.
As far as I can tell, the two sides of the debate are:
1. Weak links should break during lockout, or other extreme towing circumstances, thus saving the pilot's bacon. Sure, a weak link that is weak enough to break during lockout may also break at random, unpredictable times but that is ok with me because I feel safer overall knowing that I have the weak link as a backup release mechanism.
and on the other side
2. Weak links should never break unless the glider and/or tug is about to fail structurally. This is because a weak link that is any weaker may break at random, unpredictable times and that is very dangerous.
Flip a coin. Do whatever the fuck you want.
Zack C - 2012/08/17 19:25:23 UTC
I started using a stronger link because I had finally arrived at an understanding of what a weak link is for and what it can and cannot do. It just so happened the break on video occurred around the same time.
And now the thing might not break when you need it to...
Not a chance. It only needs to break before the glider, and the glider will never be anywhere near stressed with the weak link I'm using.
If you think the weak link might 'need' to break under some other circumstances, please tell us when a weak link should break and how you determine the breaking strength that will ensure it does in those circumstances.
Naw... You want me to make bold black and white statements so that you can have a go.
Unfortunately that's not what you're getting.
Some people listen with the intent of understanding.
Others do so with the intent of responding.
Jim Rooney - 2013/02/17 00:34:14 UTC
Ok, I've got a few minutes to write ya up something a bit more.
You need to understand something here that you're really not getting yet.
You are talking as if I or "we" need to justify something to you.
This is 180deg off.
YOU are the one arguing with a system that's been in place and has been worked on over quite literally HUNDREDS of THOUSANDS of tows.
The onus is on YOU.
Not the other way around.
"We" don't need to justify jack.
You want to take pot shots... go for it. I couldn't give a toss.
You don't like my answers... again, get bent.
You're the newbie.
You want to bring in something new?... go for it... it's to YOU to justify it.
It is not to us to justify what we do.
We've been at this a long time and have gone over and over all these little arguments before that you think are "new".
They're new to you.
But they're old hat to "us".
Zack - I choose not to get on the Tad part 2 merry-go-round. But please enjoy yourself.
Zack Marzec also chose not to get on the Tad part 2 merry-go-round. Instead he chose to get on the Flight Park Mafia 130 pound Greenspot roller coaster. Sometimes it pulls out in time, sometimes it don't.
Zack C - 2012/08/17 21:09:03 UTC
Paul (pjwings, that is),
I think you have the right general idea, but I have to correct and clarify some things. I say 'think' because I can only speak for the side I'm on. I have a hard time getting the other side to tell me when a weak link should break or what its breaking strength should be (as you might have been able to tell).
Weak links should break during lockout...
Stronger weak links will still break during a lockout if the pilot doesn't release. It will just take slightly longer.
Weak links should never break unless the glider and/or tug is about to fail structurally.
I wouldn't say 'about to fail'...they should break well below that to leave a safe margin. I'd say they should break well above anything that would normally be encountered on tow but well below what would break the aircraft. That allows a pretty big range.
This is because a weak link that is any weaker may break at random, unpredictable times and that is very dangerous.
Weak link breaks are usually nothing more than inconveniences. But with just the right combination of factors they could be much worse.
...a weak link that is weak enough to break during lockout...
Lockouts only matter near the ground (at altitude, the weak link, no matter how strong it is, will break and the glider recover if the pilot doesn't release). If a lockout occurs near the ground, you do not want to rely on any weak link to save you. If it's strong enough to get you to altitude, it's strong enough to permit a very bad attitude that could be catastrophic near the ground (as illustrated by the earlier video I posted). That's why they say the weak link isn't there to protect the pilot.
For any given lockout that ends in a weak link break, there's a breaking altitude below which the pilot will not be able to prevent a crash. If you use a stronger weak link, that altitude will be a little higher. Using the weaker weak link will only matter if the lockout occurs between those two altitudes, so you'd basically be gambling that at some point you'll need it to break in this range in exchange for a much greater chance of it breaking at a bad time.
Jim Gaar - 2012/08/17 22:12:29 UTC
This is GOLDEN for all of us that tow (I tow a lot on a PL rig). It holds true for ANY towing system. Zack you are doing a great job of shining the light on the weaklink issues. It's really that simple to me. I am going to start using 205 leech. I was using 4 strands of 130 kite string (standard AT stuff). Thanks
Can you explain, then, exactly how we arrived at the current 130 lb weak link standard?
Jim Gaar - 2013/02/13 17:57:05 UTC
Former Flight Park Manager
Because it has the best known and accountable safety record (in my personal books anyway).
Fuck you, Rodie.
Zack C - 2012/08/17 23:25:41 UTC
It holds true for ANY towing system.
The purpose of the weak link is the same for any tow method, but what you quoted is not entirely applicable to payout winch towing because it's tension controlled. While a weak link will eventually break at some point in the course of an aerotow lockout, this is generally not the case on a payout winch because the drum will just pay out faster rather than allow tension to increase. It thus makes even less sense to use lighter weak links with payout winch towing.
I am going to start using 205 leech. I was using 4 strands of 130 kite string (standard AT stuff).
For AT or PL? How many strands of 205? At the end of a V bridle or directly engaging the towline?
Four strands of 130 will break around 200 lbs (not the 520 often assumed).
Here in Houston we use four strands (two loops) of 205 leech line directly engaging the towline for platform towing. We've tested this configuration to break around 600 lbs.
That's two or three times the strength you should be using! You'd better check that.
General guidelines is to use a "1G" weak link, with a breaking strength roughly equal to your all-up weight - you, glider, harness, etc.
When we platform tow in rough air, and the consequences of a weak-link break aren't great, we go as far as a 300 pound weak link. (Yeah, I know, bad!) But not double that!
A three hundred pound (towline) weak link - forty pounds over what Zack Marzec was using - that would've killed him just as dead.
Zack C - 2011/08/13 03:23:51 UTC
Just about all of us here in Houston use 600 lb weak links.
The purpose of the weak link is to prevent structural failure of the glider. A glider is not in danger of failing with a 600 lb weak link. The group here has been towing with these for decades and has never seen a structural failure.
Why is a 1 G weak link recommended?
We use stronger mainly because a weak link break at the wrong time can cause a stall near the ground.
And, as Zack C got ZILCH in the way of a response from that useless fucking asshole at that time we got ZILCH in the way of and hint of useful participation from that useless fucking asshole in any of the Zack Marzec discussions.
Paul Edwards - 2012/08/18 00:55:41 UTC
Thanks Zack! That clarifies it well. Seems like a very subtle difference to raise such ire. Either way unplanned breaks are possible. Either way the weak link will pop long before the aircraft does. It just comes down to a matter of degree... And which set of variables a pilot is most comfortable towing with.
- Bullshit.
- And thanks for all your participation in the discussions at the end of last winter.
Zack C - 2012/08/18 01:16:26 UTC
I suspect nearly all pilots using a good release and following USHPA's weak link recommendation will never see a weak link break - just as in the sailplane world.
Jim Gaar - 2012/08/18 04:33:30 UTC
It thus makes even less sense to use lighter weak links with payout winch towing.
Exactly. I was going to say that with the payout you just keep on locking out as the weak link fails to pop. We are all about the PIC releasing BEFORE anything gets too out of whack. And if it does finally break you get a whip stall maybe or you just end up low, fast and going downwind!
For AT or PL? How many strands of 205? At the end of a V bridle or directly engaging the towline?
For PL. At least three at the end of my 3 string release, directly engaging the towline loop.
Four strands of 130 will break around 200 lbs (not the 520 often assumed).
Yes I have personal experience with that knowledge.
I didn't post this info when this thread was 'live' as at the time an accident report was pending.
On the 12th August a new(ish) pilot took off on tow, his weak-link snapped, the glider's nose dropped and with no height to recover he hit the ground.
Now you can dress this incident up as much as you like but what put the guy in hospital was his 'safety device'.
If the weak-link had held he would have had a post flight briefing instead of a trip in a helicopter.
It is true the guy made some mistakes and was not a perfect pilot.
The weak-link sure taught him a lesson, perhaps we should also have given him a good kicking while he was on the ground waiting for the air ambulance.
A stronger weak-link, by that I mean one not teetering on the edge breaking under normal flight conditions, would drastically reduce the above risk.
This, the same risk we all (with current thinking) subject ourselves to on EVERY take off as we fly through the "Cone of Danger"
(smartarse comment acknowledged).
Now, this same guy in all probability will go through his whole flying career without suffering a lockout, he may well experience the onset of a lockout and of course release, as we are all trained to do.
At this onset why would the guy (with a stronger link) wait for his weak-link to break instead of releasing?
If he does wait he can be just as upside down with a weaker link than one that has given him the luxury of a reduced risk on every takeoff he has ever made.
One day we will look back and wonder why we endure this unnecessary risk at such a critical time, just like we now look back and wonder why we thought towing from the middle of the base bar was such a good idea, 'cos that's how everyone does it.
Wow...
So you know what happened then?
OMG... thank you for your expert accident analysis. You better fly down to FL and let them know. I'm sure they'll be very thankful to have such a crack expert mind on the case analyzing an accident that you know nothing about. Far better data than the people that were actually there. In short... get fucked.
Again, tell me how all this nonsense is about "safety"?
So, a stronger weaklink allows you to achieve higher AOAs... but you see high AOAs coupled with a loss of power as *the* problem? So you want something that will allow you to achieve even higher AOAs?
Are you NUTS?
I'm tired of arguing with crazy.
As I said many times... there are those that listen with the intent of responding... you unfortunately are one.
You've done a great job of convincing me never to tow you.
Thank you for that.
Mission accomplished.
(The guy is ok, recovering and hopefully will want to fly again.)
isn't OK and won't be recovering and flying again.
Brad Barkley - 2012/09/22 23:08:52 UTC
From Tracy and Lisa's article mentioned in this thread:
So, the typical weak link used for aerotowing most hang gliders, made as a single loop from 130 lb. line, will have a nominal 1G breaking strength of 260 lbs. and be legal for both the very small, light glider and the heavier, larger glider--assuming there is no reduction in strength of the weak link due to a knot in the line...And these are extreme cases. When we look at gliders and pilots of more average size, the standard 260 lb. weak link placed on the end of the V-bridle is FAA-legal for most gliders and pilots, and closer to the USHPA nominal 1G recommendation.
Did anyone here bother to read Drs. Lisa Colletti and Tracy Tillman's thirteen page idiotic article in the June issue of USHPA's worthless magazine?
NMERider - 2012/06/06 03:25:09 UTC
You are being much too complimentary IMHO. I got so nauseated reading it I had to take a breather. Do you mean to tell me they wrote an article that wasn't insipid and self-congratulatory to the extreme? I've found their entire series on aerotowing to come off rather poorly to say the least. A sad waste of such exalted and highly qualified medical professionals. How do I know this? Well they won't stop patting each other on the back about how great they both are.
Pardon me while I puke.
For those of you who I know only through this forum, I have an article in the USHPA magazine, this month. It's just my story, how I came to flying a couple of years ago, and why I love it so much. The title is simply "Flying," and I hope all my HG brothers (and sisters) here will check it out.
Yeah but he's also a real HG pilot with a real story. And his occupation gives him a little credit when it comes to comparing writing styles.
Nuthin' like a professional fiction writer to zero in on quality writing about aviation issues.
Also mentioned in this thread, this breaking strength assumption is not correct, as has been experimentally verified many times by many sources.
For an S2 155, 160 lbs would put you at around 0.9 times the MCOW. Legal, but barely so, and far below 'the USHPA nominal 1G recommendation' (i.e., your hook in weight plus the glider's weight).
Brad Barkley - 2012/09/23 15:12:10 UTC
It's what they use at their own flight park.
Well, if somebody running a flight park uses something the reason can only be that it's the best possible option for the job.
Zack C - 2012/09/23 16:21:08 UTC
They think they're following their own recommendations and the FAA regulations.
No they don't. There is NOTHING in the aerotow industry that's more threatening to it than solid figures on weak link strengths. Solid weak link figures are to the aerotowing industry what the hook-in check is to the foot launch instruction industry.
Once hang gliding starts implementing dangerous procedures, policy, equipment - standup landings, hang checks, Hewett Links, releases within easy reach, Birren Pitch and Lockout Limiters - and starts crippling and killing people as consequences - you can BET THE FARM that it will NEVER back off, admit the mistake, fix the problem, tolerate anyone who attempts to fix the problem.
It is my belief that NEVER ONCE in the global history of hang gliding has a mainstream school or instructor taught students hook-in checks. And if anyone can point to the slightest scrap of evidence to the contrary please do so.
Trisa's doing what everyone else is doing and everyone else is doing it 'cause everyone else is doing it and has always done it that way. And Trisa wrote that half a magazine's worth of crap to confuse, bore, nauseate everyone enough to distract them from the fact that what everyone's doing is flagrantly illegal and dangerous. Crap like that doesn't get written by accident.
I'm just saying actually follow them.
Good freakin' luck.
Chris McKeon - 2012/09/23 16:36:10 UTC
California
Safe towing realese set up
I realize that I am asking a question that is not on task, so to speak. But, I figure if all of you are into towing. Maybe one of you could turn me on to system, a set-up as in how the towing force/line is released. It has always seemed to me that one would not want to being taking one's hands off the control frame while things are getting out of shape, providing they are. So, please show me your systems for disconnecting yourself from the Tow Line.
I just buried my friend and you want me to have a nice little discussion about pure speculation about his accident so that some dude that's got a pet project wants to push his theories?
Deltaman loves his mouth release.
BFD
I get tired as hell "refuting" all these mouth release and "strong link" arguments. Dig through the forums if you want that. I've been doing it for years but unfortunately the peddlers are religious in their beliefs so they find justification any way they can to "prove" their stuff. This is known as "Confirmation Bias"... seeking data to support your theory... it's back-asswards. Guess what? The shit doesn't work. If it did, we'd be using it everywhere. But it doesn't stand the test of reality.
AT isn't new. This stuff's been worked on and worked over for years and thousands upon thousands of tows. I love all these egomaniacs that jump up and decide that they're going to "fix" things, as if no one else has ever thought of this stuff?
How many posts on this stuff have we made on The Jack Show? If you were really interested in this issue you couldn't have helped tripping over us.
Dennis Wood - 2012/09/23 18:28:23 UTC
Suffolk, Virginia
just speaking to the forces applied to the weak links. in a pro-tow situation, the force is divided between two points, i.e. at each shoulder, so if force is split into two equal parts, how much is it? now on a keel tow, again the force is split. before complaining about how strong a weak link is, look at the different rigs and see how it is used.
Why do you need to tell us this? This isn't Day One material for all the AT students you Currituck assholes run through your program? How come it's not up on Kitty Hawk's website?
Carole Sherrington - 2012/09/23 23:52:53 UTC
If it's got to the point where you have to release because of an impending lock-out, taking your hands off the control bar won't make much of a difference.
I'm gonna assume you're not speaking from experience 'cause you're still alive running your idiot mouth.
Most people in the UK who tow with a static winch use a Koch-type 2-lever release and use that for aerotowing too.
The fact that they use it for aero too speaks volumes.
Note: STUPIDLY neglected to include Dennis Pagen in the list of USHGA officials and authorities who would have had to have reviewed, been consulted on, participated in the preparation of and/or approved the report on this tragic incident. Omission recently rectified.
http://www.ushpa.aero/safety.asp
USHPA - Safety Articles
Fatality Reports
Fatality Report 2013 (PDF)
Hang Gliding and Paragliding Fatalities Jan 2013 Through July 2013
Hang Gliding Fatalities
2013/02/08 - Zack Marzec
Zack Marzec (27), an H-4 Pilot with Aero Tow and Tandem Aero Tow proficiency as well as Advanced Instructor and Tandem Instructor appointments, and a USHPA member since 2009, suffered fatal injuries when when his glider tumbled during an aero tow launch. During the launch, at an altitude of 150 AGL, the pilot encountered an invisible bullet thermal which pitched the nose up, causing the weak link to break. Upon the breakage of the weak link, the glider whip stalled and then tumbled twice. The pilot and glider's leading edge hit the ground simultaneously. The pilot was utilizing his own pro-tow style tow harness, this own high performance glider with VG on, and was not wearing a full face helmet.
2013/02/08
2013/02/02 - motherfuckers. Groundhog Day. Five days BEFORE you gutted the SOPs to bring Quest's operation in line with them. Hoping for another one just like it - preferably with Rooney or Davis - same time next year.
During the launch, at an altitude of 150 AGL, the pilot encountered an invisible bullet thermal...
Zack hit the lift a few seconds after I did. He was high and to the right of the tug and was out of my mirror when the weak ling broke. The load on the tug was not excessive as with a lockout, but I was not surprised when the weak link broke. I was still in the thermal when I caught sight of Zack again. I did not see the entry to the tumble, but I did see two revolutions of a forward tumble before kicking the tug around to land. The thermal was still active in the area that I had just launched from so I did a go round and landed on a runway 90 degrees cross to the direction we were towing in.
Mark Frutiger - 2013/02/09 02:31:37 UTC
The turbulance level was strong, among the strongest thermal activity I've felt leaving the field. I've encountered stronger mechanical mixing, but the vertical velocity this time was very strong.
- The thermal was strong, wide, relatively smooth, sustained, and within the range of what could be expected and has been experienced leaving that field.
- The Dragonfly couldn't see it coming but - with the aid of reliable, steady, uninterruptable thrust - had no problem whatsoever dealing with it.
- Compare/Contrast with what happens to a Dragonfly on a normal tow in smooth air when it has its power cut abruptly at eighty feet:
- Once the tug was in it he didn't need to see it to fully assess its potential threat. Being in it he could, in fact, better assess its potential threat than he would have been able to by watching dust and dry grass, had it been present, prior to flying into it.
- Zack, by seeing the thermal's effect on the tug, knew EXACTLY what he would be dealing with in about five seconds. For him the thermal was TOTALLY visible. People who fly hang gliders a lot tend to be pretty good at judging how fast chunks of air are going up by watching other planes and birds flying into it.
- Neither pilot considered the thermal to be problematic to abort the tow.
- And Mark makes no mention of other tows he's pulled into similar strength thermals at similar low altitudes being aborted.
- The tow was aborted on the call of the fishing line which overrode the decisions of both pilots to continue the tow.
- And that was the point of the beginning of the real problems - big surprise.
...which pitched the nose up...
- How come the tug doesn't report a problem with his nose getting pitched up? Could it possibly be that the tow bridle...
...was in compliance with the Aerotow Equipment Guidelines...
The United States Hang Gliding and Paragliding Association, Inc. - 2013/01/23
12. Standard Operating Procedure
10. Towing/Aerotowing Administration
09. Aerotow Pilot Appointment (ATP)
-B. Aerotow Equipment Guidelines
02. The tow line connection to the towing vehicle must be arranged so as to not hinder the control system of the towing vehicle.
...USHGA published just ten days prior to the crash while the glider's tow bridle, for which there are no comparable guidelines, was using a bridle configuration...
...which seriously compromised his pitch control range? I mean, in the 2005/01 issue of Hang Gliding you published a fatality report...
Dennis Pagen - SUMMER 2004 ACCIDENT REPORTS
FATAL TOWING ACCIDENT
The first accident occurred in Germany at an aerotowing competition. The pilot launched with his Litespeed and climbed to about forty feet when he encountered a thermal that lifted him well above the tug. After a few moments, the glider was seen to move to the side and rapidly turn nose down to fly into the ground, still on tow, in a classic lockout maneuver. The impact was fatal.
This pilot was a good up-and-coming competition pilot. He had been in my cross-country course three years ago, and this was his second year of competition. What happened to him is not too unusual or mysterious. He encountered so much lift that although he was pulling in the base bar as far as he could, he did not have enough pitch-down control to get the nose down and return to proper position behind the tug. This situation is known as an over-the-top lockout.
I am personally familiar with such a problem, because it happened to me at a meet in Texas. Soon after lift-off the trike tug and I were hit by the mother of all thermals. Since I was much lighter, I rocketed up well above the tug, while the very experienced tug pilot, Neal Harris, said he was also lifted more than he had ever been in his heavy trike. I pulled in all the way, but could see that I wasn't going to come down unless something changed. I hung on and resisted the tendency to roll to the side with as strong a roll input as I could, given that the bar was at my knees. I didn't want to release, because I was so close to the ground and I knew that the glider would be in a compromised attitude. In addition, there were hangars and trees on the left, which is the way the glider was tending. By the time we gained about 60 feet I could no longer hold the glider centered--I was probably at a twenty-degree bank--so I quickly released before the lockout to the side progressed. The glider instantly whipped to the side in a wingover maneuver. I cleared the buildings, but came very close to the ground at the bottom of the wingover. I leveled out and landed.
Analyzing my incident made me realize that had I released earlier I probably would have hit the ground at high speed at a steep angle. The result may have been similar to that of the pilot in Germany. The normal procedure for a tow pilot, when the hang glider gets too high, is to release in order to avoid the forces from the glider pulling the tug nose-down into a dangerous dive. This dangerous dive is what happened when Chris Bulger (U.S. team pilot) was towing John Pendry (former world champion) years ago. The release failed to operate in this case, and Chris was fatally injured. However Neal kept me on line until I had enough ground clearance, and I believe he saved me from injury by doing so. I gave him a heart-felt thank you.
The pilot in the accident under discussion was an aerodynamic engineer. He had altered his glider by lengthening the front cables and shortening the rear cables to move his base tube back. The amount was reportedly ten centimeters, or about four inches. This is well within the acceptable range, according to Gerolf Heinrichs, the Litespeed designer. Why the pilot altered his bar position in this manner is anyone's guess, but my guess is that it was because he felt the bar was too far out on the glider with the VG off. This Litespeed was the pilot's first topless glider and I expect he wasn't informed that most of the new topless gliders experience a great movement of the base tube as the VG is pulled through its range. The result is that the bar is so far out and the pitch pressure so strong that with the VG off, that the standard procedure is to take off and land with at least a quarter VG. If the pilot didn't know this he would have been tempted to move the bar.
Factors that attributed to the accident in various degrees were the pilot's experience, the conditions and the alteration of the base tube. To begin, he wasn't greatly experienced in aerotowing, although he had learned and spent much of his flying with surface tow. It is difficult to assess the effect of the turbulence, but suffice it to say that it was strong enough to project him upward, well above the tug. Finally, the alteration of the basetube position could have been a contributing factor because he certainly would have had more pitch authority if he hadn't done that. It is impossible to tell, but perhaps the thermal that lifted him would not have done so as severely if he had had a bit more pitch travel.
What We Can Learn
To begin, alteration of our gliders should not be done without full agreement and guidance from the factory or their trained representatives. Even with such approval, be aware that the factory might not know how you will be using your equipment. Changing the pitch range of a glider is a fairly serious matter and should only be done with full understanding of all the effects.
Secondly, over-the-top lockouts are not frequent, but common enough in big-air towing that tow pilots should all have a plan to deal with them. Think about this: When we are lifted well above the tug, the tow system forces becomes similar to surface towing, with the limit of tow force only being the weak link. The susceptibility to a lockout is increased in this situation.
My experience leads me to believe that a strong thermal hitting when low can push you vertically upwards or sideways before you have time to react. If this happens when I am low, I fight it as hard as I can until I have clearance to release safely. If I am high above the tug, I stay on line with the bar pulled in as far as possible and keep myself centered if at all possible. I fully expect the tug pilot to release from his end if necessary for safety, but in the case of a malfunction, I would release before endangering the tug.
We are taught to release at the first sign of trouble, and I fully support that general policy, but in some cases, the trouble happens so fast and is so powerful that a release low would have severe consequences. In my case, I was instantly high above the tug with a strong turn tendency and a release at that point would have been ugly. The main point for us to understand is that we must gain our experience in gradually increasing challenges so we can respond correctly when faced with different emergencies. It should be made clear again that a weak link will not prevent lockouts and a hook knife is useless in such a situation, for the second you reach for it you are in a compromised attitude.
Thirdly, experienced pilots should be aware that towing only from the shoulders reduces the effective pull-in available to prevent an over-the-top lockout. Like many pilots, I prefer the freedom of towing from the shoulders, but I am aware that I must react quicker to pitch excursion. Sometimes reactions aren't quick enough and emergency procedures must be followed. It seems to me that we shouldn't be overly eager to encourage lower airtime pilots to adopt this more advanced method of aerotowing.
...which included a report of a near fatal very similar incident experienced by the reporter and much was made of the bridle configuration which wiped out a great deal of the pitch control range for which the glider was certified.
And Dennis says:
What happened to him is not too unusual or mysterious.
If it's not too unusual or mysterious shouldn't we fix the problem before too many more people are killed?
...causing the weak link to break.
- Causing WHAT weak link to break?
-- Hell, just a little over eight months before the crash you published a very extensive fourteen page article detailing our expectations for loops of 130 pound Greenspot and how to tie them such that they break as early as possible in lockout situations but be strong and reliable enough to avoid frequent breaks from turbulence.
-- Fourteen pages centering on how to Wrap and Tie a loop of 130 pound Greenspot so it breaks reliably as early as possible in lockout situations at 260 pounds but not unreliably and frequently in turbulence at 130 pounds the way a Pre-Tied 130 pound Greenspot loop does - and you can't tell us ANYTHING about THE weak link other than pitching up caused it to break?
Dr. Trisa Tilletti - 2012/06
Russell Brown, a founder of Quest Air in Florida and a well-known Dragonfly tug pilot, is also a sailplane pilot, tug pilot, and A&P mechanic for a large commercial sailplane towing operation in Florida. He told us that, like us, he has never seen a sailplane weak link break, either. Russell owned the first 914-powered Dragonfly ever made--he helped us build the second one, which we still fly. He is the one who, many years ago, showed us the method for making a WT weak link and suggested we use polypropylene rather than Spectra for hang glider V-bridles.
I'da thunk for sure that RUSSELL BROWN - a cofounder and co-owner of the flight park where Zack crashed and strong advocate of 260 pound Wrapped and Tied fishing line - would've have used this golden opportunity to promote his more reliable weak link to the benefit of us all.
- So you're saying that the pitching up of a glider causes "the" weak link to break? Is it a good idea to fly with something in the system that causes the glider to be dumped off tow when the glider pitches up? Is that a good idea?
- What's the purpose of "the" weak link? In the 2013/01/23 SOPs you state:
The United States Hang Gliding and Paragliding Association, Inc. - 2013/01/23
12. Standard Operating Procedure
10. Towing/Aerotowing Administration
09. Aerotow Pilot Appointment (ATP)
-B. Aerotow Equipment Guidelines
06. The purpose of the weak link is to protect the tow equipment, and may not prevent lockouts or other abnormal flight conditions.
Protect WHAT tow equipment? The towline, tow ring, pro-tow style tow harness, bent pin barrel release? At the expense of dumping the glider into a whipstall when the glider pitches up? Is that a good idea? Wouldn't it be better to risk stressing out the tow equipment than to guarantee that the glider is dumped into a whipstall when it pitches up? You can replace the tow equipment Zack was using for about fifteen bucks - a good topless glider can run around seven grand.
- Would it be possible to use as stronger weak link than the one Zack was using that would protect the tow equipment but be less likely to dump the glider into a whipstall when it pitched up? Your 2013/01/23 SOPs state:
04. A weak link must be placed at both ends of the tow line. The weak link at the glider end must have a breaking strength that will break before the towline tension exceeds twice the weight of the hang glider pilot and glider combination. The weak link at the tow plane end of the towline should break with a towline tension approximately 100 lbs. greater than the glider end. Weak links must be used in accordance with 12 CFR 91.309(a)(3). The USHPA recommends that a nominal 1G (combined operating weight of the glider and pilot) weak link be used, when placed at one end of a hang glider pilot's V-bridle; or about 1.5-2G if placed at the apex of the tow bridle or directly in-line with the tow rope. The actual strength of the weak link used by the hang glider pilot must be appropriate for the operation and have a breaking strength between 80% and 200% MCOW (max. cert. operating weight) of the glider, in terms of direct towline tension. 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.
Was Zack flying in that 1.5 to 2.0 G range USHGA recommends? If not...
Mark Frutiger - 2013/02/08 19:12:21 UTC
The load on the tug was not excessive as with a lockout, but I was not surprised when the weak link broke.
...wouldn't it be a good idea to emphasize that recommendation in this fatality report?
I've personally refused to tow a flight park owner over this very issue. I didn't want to clash, but I wasn't towing him. Yup, he wanted to tow with a doubled up weaklink. He eventually towed (behind me) with a single and sorry to disappoint any drama mongers, we're still friends. And lone gun crazy Rooney? Ten other tow pilots turned him down that day for the same reason.
Again, tell me how all this nonsense is about "safety"?
So, a stronger weaklink allows you to achieve higher AOAs... but you see high AOAs coupled with a loss of power as *the* problem? So you want something that will allow you to achieve even higher AOAs?
Are you NUTS?
I'm tired of arguing with crazy.
As I said many times... there are those that listen with the intent of responding... you unfortunately are one.
You've done a great job of convincing me never to tow you.
Thank you for that.
Mission accomplished.
...none of your idiot fucking tug drivers will pull anybody who wants to fly in the USHGA recommended range?
Upon the breakage of the weak link, the glider whip stalled and then tumbled twice.
Are there any implications for the equipment we're using here?
In 1975/09 you published an article by Harry Robb in "The Tow Line" series...
Polyethylene or polypropylene, 12 strand, braided 3/8 inch line, 500 feet in length is used in competition. Lines for novice flyers should be about 150 feet long, and increased in length as experience is gained. According to the Kiting Handbook by Dan Poynter, this size line has a tensile strength of 2025 pounds.
Each end of the tow line is normally provided with a stainless steel screw-pin shackle with an approximate 3/16 inch shank which fits in the slot of the safety release hook. The screw pin of the shackle is inserted through a loop of the tow line at least 2 or 3 feet, providing sufficient friction to prevent disengagement. Although some flyers use only the loop of the tow line in the safety release, this practice is not recommended as it greatly accelerates the abrasion and fraying of the line.
Once the line shows very many single strand breaks, its tensile strength is greatly decreased and should be discarded. No flight should ever be made with a knot in the tow line. Aside from the abrasion caused by the knot rubbing on itself, the tensile strength is decreased by as much as 50%. Lines require constant inspection - prior to the first flight of every day by every flyer. In a tournament, the Lineman Starter can inspect some portions of the line on each flight, and the Safety Inspector will inspect the entire line slowly, foot-by-foot, two or three times daily. The tow line is a life line and must be treated with utmost respect.
It seems that back then some of these people were greatly concerned about ensuring that nothing break in the course of a tow. Hell, even Dr. Lionel D. Hewett states in an article you published in 1983/08 that...
Now I've heard the argument that "Weak links always break at the worst possible time, when the glider is climbing hard in a near stall situation," and that "More people have been injured because of a weak link than saved by one."
...he's heard the argument that "Weak links always break at the worst possible time, when the glider is climbing hard in a near stall situation," and that "More people have been injured because of a weak link than saved by one." Might not it be a good idea to look into some of these arguments in a little more depth, determine if there's any validity to them, and make recommendations accordingly?
The pilot was utilizing his own pro-tow style tow harness...
- I'll bet he made it out of that nasty low stretch Spectra.
Dr. Trisa Tilletti - 2012/06
Unlike Spectra, polypro has some stretch to it under load--and can stretch up to 20% before breaking. It acts like a shock absorber to soften impact loads, which helps to prevent damage to the structure and hardware of the tow plane and sailplane and helps to avoid unnecessary weak link breaks.
You get a lot of unnecessary weak link breaks with Spectra. And if EVER anyone had an unnecessary weak link break...
...it would've had to have been this guy.
Dr. Trisa Tilletti - 2012/06
Another factor is the size and material used for the pilot's V-bridle. A Spectra bridle has almost no stretch, so sharp, impact loads are transferred directly to the weak link, while a polypro bridle has a reasonable amount off stretch and can act as a shock absorber and reduce the intensity of the impact load.
Without shock absorption, a Spectra bridle acts somewhat like an impact wrench on the weak link.
That Spectra acts somewhat like an impact wrench on the weak link - but apparently just...
The load on the tug was not excessive as with a lockout, but I was not surprised when the weak link broke.
...on the glider end.
- What's a "pro-tow style tow harness"? I went to your online store, purchased a copy of the excellent book, Towing Aloft, by Dennis Pagen and Bill Bryden, and could find absolutely nothing about it.
...this own high performance glider with VG on...
Your point being? Are we not supposed to aerotow our own high performance gliders with VG on? Why is it more important to know that some VG was on than the:
- glider model and size
- max certified operating weight
- actual flying weight
- manufacturer's recommendations for:
-- VG setting for tow
-- tow bridle configuration
-- weak link strength
...and was not wearing a full face helmet.
And this is relevant how? What serious injuries did he sustain that he wouldn't have with a full face helmet?
Ya know, back in the old days...
Doug Hildreth - 1990/09
1990/07/05 - Eric Aasletten - 24 - Intermediate - 2-3 years - UP Axis - Hobbs, New Mexico - Platform tow - Fatal / Head
Reasonably proficient intermediate with over a year of platform tow experience was launching during tow meet. Home-made ATOL copy with winch on the front of the truck. Immediately after launch, the glider pitched up sharply with nose very high. Apparently the angle caused an "auto release" of the tow line from the pilot, who completed a hammerhead stall and dove into the ground. Observer felt that a dust devil, invisible on the runway, contributed to or caused the relatively radical nose-up attitude. Also of concern was the presumed auto release which, if it had not occurred, might have prevented the accident. Severe head injury with unsuccessful CPR.
It's more of this crappy argument that being on tow is somehow safer than being off tow.
...fueled the crappy argument...
...that being on tow is somehow safer than being off tow we'd get some accounting...
Doug Hildreth - 1991/03
Towing competition in midday thermal conditions. Normal launch sequence to fifty feet where an apparent thermal caused glider to go into extreme nose-high attitude, accidentally releasing tow line. Hammerhead stall with head first crash onto runway. Helmet broke. Died immediately.
...of the kinds of injuries the subject sustained. And in the case of Eric Aasletten:
- it didn't matter whether or not it was a full face helmet because his face wasn't an issue
- the helmet absorbed as much energy and provided as much protection as it was capable of doing and that wasn't - and couldn't possibly have been - enough
If there HAD been a head injury involved I one hundred percent guarantee you that Quest and USHGA would've gotten half a dozen idiot helmet discussions going in order to distract everyone away from the two REAL issues - the standard aerotow weak link and pro toad bridle - same way Wills Wing got idiot discussions about idiot Screamers built into racing harnesses to distract everyone away from the issue of racing harnesses being constructed such that the parachute can get locked in the container by frame deformation in a tumble.
So it's pretty fucking obvious that Zack died of internal abdominal injuries, his helmet was totally irrelevant, and that once his Quest Link increased the safety of the towing operation his death was a foregone conclusion.
Thus we can tell EXACTLY what the primary issue was in this one PRECISELY because of what information you are and AREN'T giving us.
The United States Hang Gliding and Paragliding Association, Inc. - 2013/01/23
12. Standard Operating Procedure
10. Towing/Aerotowing Administration
09. Aerotow Pilot Appointment (ATP)
-B. Aerotow Equipment Guidelines
04. A weak link must be placed at both ends of the tow line. The weak link at the glider end must have a breaking strength that will break before the towline tension exceeds twice the weight of the hang glider pilot and glider combination. The weak link at the tow plane end of the towline should break with a towline tension approximately 100 lbs. greater than the glider end. Weak links must be used in accordance with 12 CFR 91.309(a)(3). The USHPA recommends that a nominal 1G (combined operating weight of the glider and pilot) weak link be used, when placed at one end of a hang glider pilot's V-bridle; or about 1.5-2G if placed at the apex of the tow bridle or directly in-line with the tow rope. The actual strength of the weak link used by the hang glider pilot must be appropriate for the operation and have a breaking strength between 80% and 200% MCOW (max. cert. operating weight) of the glider, in terms of direct towline tension. 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.
I'm kinda confused by a lot of this...
A weak link must be placed at both ends of the tow line.
If a weak link MUST be placed at both ends of the towline and MUST be used in accordance with 12 CFR 91.309(a)(3) which state:
A safety link is installed at the point of attachment of the towline to the glider...
how can you then recommend...
The USHPA recommends that a nominal 1G (combined operating weight of the glider and pilot) weak link be used, when placed at one end of a hang glider pilot's V-bridle...
...placing it at "one end of a hang glider pilot's V-bridle"? What happens to the protection to the tow equipment when the bridle wraps - which Jim Keen-Intellect Rooney assures us it DOES...
Oh it happens.
I have, all the guys I work with have.
(Our average is 1 in 1,000 tows)
Oh yeah... an other fun fact for ya... ya know when it's far more likely to happen? During a lockout. When we're doing lockout training, the odds go from 1 in 1,000 to over 50/50.
...over half the time in lockout emergency simulations on the fine standard aerotow equipment they use? Isn't a lockout the time when the towing equipment is most likely to need protection?
We (and many others) do not recommend using a second weaklink on the non-released end of the bridle. That weaklink is just as likely to break as the one on the other end. If the lower weak link breaks, the bridle could get caught in the towline ring, and pull the glider from the 'biner or keel, causing it to tuck. The other weaklink (on top) may not break prior to the tuck.
The weaklink should be on the released end of the bridle, and the bridle should release from the top. That way, if the bridle does get caught on the ring, it is pulling from the body, rather than from the glider, and the glider may still be controllable--in which case you can use your secondary release (or hook knife if that fails) to release.
Do you really wanna be flying at a hundred feet with an overload bent pin release engaging a thick rope and hacking away at a wrapped bridle in pro-tow style tow harness configuration while you're locking out or a quarter second later when you're locked out?
Haven't you written the regulation to violate itself?
Wouldn't using a bottom end secondary weak link twenty to fifty percent over the one on the top end really effectively deal with any wrap issue and bring the glider into compliance with the FAA regulation?
Oh...
Dr. Trisa Tilletti - 2012/06
What we have covered in this article is practical information and knowledge gleaned from the real world of aerotowing, developed over decades and hundreds of thousands of tows by experts in the field. This information has practical external validity. Hopefully, someone will develop methods and technology that work better than what we are using as standard practice today. Like the methods and technology used today, it is unlikely that the new technology will be dictated onto us as a de jure standard. Rather, to become a de facto standard, that new technology will need to be made available in the marketplace, proven in the real world, and then embraced by our sport.
...right. I forgot that you don't want anybody dictating that anyone use any technology that would bring you into compliance with FAA regulations. Hell, you've got the hook knife, right? Forget I mentioned it.
The weak link at the glider end must have a breaking strength that will break before the towline tension exceeds twice the weight of the hang glider pilot and glider combination.
I have a friend who flies a Sport 2 155 - 60 pounds - at the very bottom of the hook-in weight range - 150 pounds. He prefers to minimize the likelihood of the focal point of his safe towing system breaking when he pitches up in an invisible bullet thermal so he uses a weak link that doesn't break until he hits twice the weight of the pilot glider combo - 420 pounds.
But you say that:
Weak links must be used in accordance with 12 CFR 91.309(a)(3).
And 12 CFR 91.309(a)(3) states that:
A safety link is installed at the point of attachment of the towline to the glider or unpowered ultralight vehicle with a breaking strength not less than 80 percent of the maximum certificated operating weight of the glider or unpowered ultralight vehicle and not greater than twice this operating weight.
The maximum certificated operating weight of his glider is 310 pounds. Twice that is... hang on for a second here... 620 pounds - which is pretty close to the six hundred my buddy Zack C, who hooks into his Sport 2 155 at 200 pounds, uses for platform.
- Is he not allowed to use any of that top 200 pound range because USHGA's upper limit supersedes the FAA's?
- If he:
-- throws on a hundred pounds of ballast to get up to max hook-in is it OK if he goes all the way to 620?
-- dumps the ballast at a thousand feet on the way up does he get his rating revoked as soon as he comes back down?
The weak link at the tow plane end of the towline should break with a towline tension approximately 100 lbs. greater than the glider end.
It "SHOULD"? But it doesn't have to?
I top out my HPAT 158 at 319 pounds and wanna fly at the bottom of USHGA's recommended 1.5 to 2.0 G range - 479 pounds. Bobby Bailey - who's a fucking genius when it comes to this shit - designed the Dragonfly's tow mast to snap off at 400 pounds. I'm having a bit of a problem with that arithmetic.
If I wanna maintain that hundred pound margin I've gotta fly at 300 pounds which is 0.94 Gs which is over a half a G under the bottom end of USHGA's recommended range and about what Zack Marzec was flying. Any suggestions?
A Falcon 3 145 - max certified operating weight: 235 pounds - wants the pitch and lockout protection afforded by the minimum / 0.8 G legal weak link for that glider - 188 pounds. If the tug uses the weak link it "should" - 288 pounds - he exceeds the glider by 53 percent - over twice the FAA's legal limit. Isn't that a bit problematic with respect to the regs?
The actual strength of the weak link used by the hang glider pilot must be appropriate for the operation...
- Meaning any stupid pigfucker running a flight park, tow meet, or Dragonfly...
I've personally refused to tow a flight park owner over this very issue. I didn't want to clash, but I wasn't towing him. Yup, he wanted to tow with a doubled up weaklink. He eventually towed (behind me) with a single and sorry to disappoint any drama mongers, we're still friends. And lone gun crazy Rooney? Ten other tow pilots turned him down that day for the same reason.
...can override the FAA's 0.8 G minimum any time he feels like it, force 130 pound Greenspot down everyone's throat, and keep anyone who wants to get safely airborne...
Then again, Russell Brown had us double up behind him after six breaks in a row at Zapata. We couldn't figure out why we had so many breaks so quickly. Maybe just coincidence.
...from doing so.
- How 'bout you spell out for us what you mean by that bullshit, motherfucker?
-- Is that the Taber Clause that got put in so he can keep selling that piece of crap...
The new GT aerotow release, new as of July 11th 2009, is designed to be used with a V bridle and a 130-pound green stripe Dacron tournament fishing line weak link. At this time it is not recommended to use this release with a higher value weak link.
...he refers to as an "aerotow release"?
-- Or is that the clause you threw in so when a Zack Marzec gets whipstalled, tailslid, tumbled, and killed you can say his Rooney Link was perfectly OK 'cause it was appropriate for the operation at Quest - which has a very long track record of using Rooney Links?
The actual strength of the weak link used by the hang glider pilot must be appropriate for the operation and have a breaking strength between 80% and 200% MCOW (max. cert. operating weight) of the glider, in terms of direct towline tension.
Translation...
- A weak link appropriate for about any AT operation you wanna name is 130 pound Greenspot.
- On a glider bridle that approximates the safety specifications defined for the tug the max tension is 226 pounds.
- If the max certified operating weight is 283 pounds or over it can't fly legally.
...and have a breaking strength between 80% and 200% MCOW (max. cert. operating weight)
USHGA Aerotow Guidelines - 1985/07
USHGA Safety and Training Committee
II AEROTOWING EQUIPMENT
3) A weak link must be placed between the tow line and the release at both ends of the tow line with the forward link ten percent stronger than the rearward weak link. The weak link must have a breaking strength less than 85% the weight of the hang glider and pilot combination, not to exceed 200 pounds.
- No minimum. If you were maxed out on your glider at
-- 235 pounds or under you could fly at 0.85 Gs tops
-- 250 pounds you could fly at 0.80 Gs
- Anything over 250 you could not fly legally under the FAA aerotowing regulations which incorporated hang gliders 2004/09.
- In the early nineties the Dragonfly reared its ugly head and all gliders:
-- were:
--- conned by Flight Park Mafia quacks into flying 130 pound Greenspot
--- told a loop of 130 pound Greenspot blew at 260 - twice its actual strength
-- 283 pounds and over were flying below the FAA minimum
The United States Hang Gliding and Paragliding Association, Inc. - 2011/11
Standard Operating Procedure
12. Rating System
02. Pilot Proficiency System
12. Hang Gliding Aerotow Ratings
-C. Aerotow Equipment Guidelines
04. A weak link must be placed at both ends of the tow line. The weak link at the glider end must have a breaking strength that will break before the towline tension exceeds twice the weight of the hang glider pilot and glider combination. The weak link at the tow plane end of the towline should break with a towline tension approximately 100lbs. greater than the glider end.
Even though we've been covered under FAA aerotow regulations for over seven years at that point USHGA continues to use what they've had on the books for probably twenty years or more:
- a more restrictive maximum for any glider not maxed out
- no:
-- minimum
-- no acknowledgement of the FAA regs
This is a very deliberate deception by the USHGA cult leaders.
- Hang glider towing was built on the foundation that there's no towing problem that can't be solved by a towline failure and the most severe consequence one can experience from a towline failure is a wee bit of inconvenience.
- They've spent the previous twenty years selling rot like Towing Aloft which is full of crap like:
Caution: For aerotowing tandem, weak links should be lighter than for surface towing tandem. One commercial aerotow operation (Wallaby) uses the same weak link for tandem towing as they use for solo with very good results and a wide safety margin.
Hang gliders aerotowing
- 80% to 100% of total weight solo.
- 80% or less for tandem.
Ultralight sailplanes aerotowing
- 75% or less of total weight.
- See manufacturer's recommendations.
- They know bloody well that:
-- they've been crashing gliders left right with mostly illegal standard aerotow weak links
-- all tandems pulled by Dragonflies are operating in flagrant violation of FAA regulations
-- the crap from 1985 mandating maxes of 200 pounds or 85 percent of flying weight, whichever comes first, will be very difficult to explain
The United States Hang Gliding and Paragliding Association, Inc. - 2013/01/23
12. Standard Operating Procedure
10. Towing/Aerotowing Administration
09. Aerotow Pilot Appointment (ATP)
-B. Aerotow Equipment Guidelines
04. The actual strength of the weak link used by the hang glider pilot must be appropriate for the operation and have a breaking strength between 80% and 200% MCOW (max. cert. operating weight) of the glider, in terms of direct towline tension.
So Trisa... What's the deal with this eighty percent MINIMUM?
I read your article in the 2012/06 issue of the magazine and found the following OBVIOUS issues related to the maximum...
There has been a trend lately for some tandem operators to go with about a 400 lb. weak link on both the tandem glider and tug V-bridles, rather than 520 lbs., to help protect the equipment from large stresses.
Tandem weak links over four hundred pounds - 0.7 Gs on a Falcon 3 Tandem - may not help protect the equipment from large stresses - especially when the equipment includes a Dragonfly tow mast breakaway designed by a fucking genius to break away at about four hundred pounds towline tension. Hell, look what happened to this tandem...
I know personally of another incident that occurred this year in a tandem (not at Quest, not with me). A pilot with limited tandem experience took up a tandem passenger behind a tug pilot with limited midday experience. The hang gliding pilot had difficulty controlling the glider's pitch due to bad flying on the tug pilot's part. He should have released earlier, but didn't.
By the time the glider released the tandem had been stressed pretty hard. The tandem pilot safely landed the tandem. Afterwards, while examining the glider to ensure that it had not been overstressed, it fell apart on the ground. Very lucky it was not a double fatality.
The pilot will report this in a timely fashion but it is not my place to reveal details. The weak link did not break.
Being stuck to the plane is not always good.
...with a four strand weak link on the glider's bridle and a three strand tow mast breakaway on the tug's bridle - and that glider didn't even lock out. I shudder to think what would've happened to a solo glider that did.
If tandem operators think that, practically, a 520 lb. double loop weak link is too much for a tandem, it is way too much for a solo pilot.
If tandem operators think that, practically, a 520 pound double loop weak link - which actually blows at around 200 pounds - is too much for a tandem, it is way too much for a solo pilot. And, in a sport founded and operated entirely on opinions, what possible parameter could be more important than what a tandem operator...
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.
I am posting the report my husband, Paul Tjaden, just wrote about Zach Marzec's death at Quest. It is a great tragedy to lose someone so young and vital. We are sick about it, and our hearts go out to his friends, family and loved ones.
You are being much too complimentary IMHO. I got so nauseated reading it I had to take a breather. Do you mean to tell me they wrote an article that wasn't insipid and self-congratulatory to the extreme? I've found their entire series on aerotowing to come off rather poorly to say the least. A sad waste of such exalted and highly qualified medical professionals. How do I know this? Well they won't stop patting each other on the back about how great they both are.
Pardon me while I puke.
Hahahahahahahahaha
Oh that's just rich!
Riiiiiight... it's my attention span at issue here....
and I'm the one that's arrogant!
HAHAHAHAHAHAHAAHAHA
No, I'm not being nice. No, I do not feel the need to be nice. You're trying to convince people to be less safe. I don't want to be on the other end of the rope when someone listening to this drivel smashes in.
I've heard it a million times before from comp pilots insisting on towing with even doubled up weaklinks (some want no weaklink). I tell them the same thing I'm telling you... suck it up. You're not the only one on the line. I didn't ask to be a test pilot. I can live with your inconvenience.
Please tell me again what's wrong with the wheel? Why you keep trying to reinvent it?
...a million comp pilots... Only a total moron would side with the million comp pilots. Who ever heard of a SOLO pilot being able to understand the physics of aerotowing, think for himself, and make his own aviation decisions?
If a tandem operator says that a loop of 130 pound Greenspot on a bridle end translates to 360 pounds of towline tension and...
The normal braking force in pounds for a weak link is around 180, at least that is the regular weak link line used at most aerotow operations. By adding a second weak link to your bridal you are cutting the load on each link by half, meaning that the weak link will not break at the intended 180 pounds but it will need about 360.
If that is what you use and is what your instructor approved then I have no business on interfering, i dont know if you are using the same weak link material but there shoul be only ONE weak link on a tow bridle for it to be effective in breaking before higher loads are put into you and the glider should the glider gets to an attitude or off track so much that the safety fuse of the link is needed to break you free from the tug.
...loops on both ends bring the towline tension up to 720 who are we weekend warrior muppets to argue otherwise? Hell, if TWO tandem operators are saying the same thing...
I made the same mistake on putting two weak links thinking that I was adding protection to my setup and I was corrected by two instructors on separate occacions at Quest Air and at the Florida RIdge.
...we should probably play it safe and assume that the towline tension goes to 1440.
Solo hang glider pilots should not place a 520 lb. double loop weak link on their V-bridle, unless they get specific approval from the tow operator. It could be hard on the equipment and could be illegal if the tug is using a weaker weak link. It is also far beyond USHPA's nominal 1g recommendation.
Solo hang glider pilots should not place a 520 minus 320 pound double loop weak link on their V-bridle, unless they get specific approval from the tow operator...
We had six weaklink breaks in a row at Zapata this year. Russell Brown (tug pilot, tug owner, Quest Air owner) said go ahead and double up (four strands of Cortland Greenspot).
Davis Straub - 2011/08/28 15:26:28 UTC
Then again, Russell Brown had us double up behind him after six breaks in a row at Zapata. We couldn't figure out why we had so many breaks so quickly. Maybe just coincidence.
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.
...it could be hard on the equipment and could be illegal if the tug is using a weaker weak link. It is also far beyond USHPA's nominal one G recommendation.
But as long as they get that specific approval from the tow operator:
- it won't be:
-- hard on the equipment
-- illegal if the tug is using a weaker weak link - which he IS
- being far beyond USHPA's nominal one G recommendation won't matter - except in terms of being able to get the gliders off the ground
Jim Lee, two-time US Hang Gliding National Champion and six-time US comp point champion, was our commercial pilot sailplane instructor. He is a sailplane distributor, instructor, and tow pilot in Florida. He recently told us that he has only seen two sailplane weak link breaks, and experienced one himself, when he and the tow plane had to turn sharply on tow to avoid a helicopter that flew into their flight path. He said that his weak link performed properly in that situation.
A heavy weak link might not perform properly when the tug and glider turn sharply to avoid a helicopter that turns into their flight path.
In addition to preventing structural failure, weak links may break: (a) to prevent loss of control of the tow plane or glider in unusual attitudes, (b) when tow forces increase as a glider gets outside of the cone of safety, and (c) sooner or later after a lockout has started.
A heavy weak link might not break:
- (a) to prevent loss of control of the tow plane or glider in unusual attitudes
- (b) when tow forces increase as a glider gets outside of the Cone of Safety
- (c) sooner or later after a lockout has started
(kinda the way...
The United States Hang Gliding and Paragliding Association, Inc. - 2013/01/23
12. Standard Operating Procedure
10. Towing/Aerotowing Administration
09. Aerotow Pilot Appointment (ATP)
-B. Aerotow Equipment Guidelines
06. The purpose of the weak link is to protect the tow equipment, and may not prevent lockouts or other abnormal flight conditions.
...any weak link capable of getting the glider airborne might not).
Actually, that is our expectation of performance for weak links on hang gliders here at Cloud 9, too. Primarily, we want the weak link to fail as needed to protect the equipment, and not fail inadvertently or inconsistently. 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. It is the same expectation of performance that we have for the weak links we use for towing sailplanes.
A heavy weak link might not meet Cloud 9's expectation of breaking as early as possible in a lockout situation - which is the same expectation of performance that they have for the weak links they use for towing sailplanes. And we've had some really scary and ugly towing incidents when weak links don't perform in accordance with our expectations:
1982/10/23 - Donnell Hewett
1985/07/17 - Chris Bulger
1992/05/17 - Dick Reynolds
1996/07/25 - Bill Bennett / Mike Del Signore
1999/12/11 - Debbie Young
1998/05/15 - Richard Graham
1998/10/25 - Jamie Alexander / Frank Spears
1999/02/27 - Rob Richardson
2004/06/26 - Mike Haas
2005/01/09 - Robin Strid
2005/05/29 - Holly Korzilius
2005/09/03 - Arlan Birkett / Jeremiah Thompson
2006/02/05 - John Dullahan
2008/05/18 - Socrates Zayas
2008/06/02 - Carlos Weill
2009/01/03 - Steve Elliot
2009/08/31 - Roy Messing
2011/10/28 - Lois Preston
2012/11/04 - Frank Murphy
2013/02/02 - Zack Marzec
Either case is legal if within FAA limits, and can be ethical and practical if it works effectively and safely for that operation. The strength of the weak link that is appropriate for a particular operation can depend on the power of the tug and resultant climb rate and climb angle of the tow.
A heavy weak link might not be ethical and/or practical at some operations...
You will only ever need full throttle for the first fifty feet of a tandem tow. Don't ever pull a solo at full throttle... they will not be able to climb with you. You can tow them at 28 mph and you'll still leave them in the dust... they just won't be able to climb with you... weaklinks will go left and right.
...particularly those with anemic tugs with crappy climb rates.
To be legal, a hang glider pilot should not just use any strength weak link they want to use, it must be within legal limits, and coordinated with the weak link used at the tug end of the rope.
A heavy weak link might not be coordinated with the weak link used at the tug end of the rope - the strength the Pilot In Command of the tow wants to use. The tug driver must be allowed to use any fuzzy piece of shit he feels like and force the glider to the rock bottom of the FAA legal range - or below - the way it's been done for several decades and hundreds of thousands of tows conducted by numerous aerotow operators across the county.
And this is ALL we've got for the MINIMUM:
These factors lead to a relatively high frequency of weak link breaks at aerotow hang gliding competitions.
Adam Parer - 2009/11/25
Airborne Gulgong Classic
New South Wales
Due to the rough conditions weak links were breaking just about every other tow and the two tugs worked hard to eventually get everyone off the ground successfully.
...where you can get a relatively high frequency of weak link breaks dumping you back into and gumming up the launch lines while the soaring window evaporates. It's not like that's an issue...
Jim Rooney - 2011/08/28 19:39:17 UTC
Weak links break for all kinds of reasons.
Some obvious, some not.
The general consensus is the age old adage... "err on the side of caution".
The frustration of a weaklink break is just that, frustration.
And it can be very frustrating for sure. Especially on a good day, which they tend to be. It seems to be a Murphy favourite. You'll be in a long tug line on a stellar day just itching to fly. The stars are all lining up when *bam*, out of nowhere your trip to happy XC land goes up in a flash. Now you've got to hike it all the way back to the back of the line and wait as the "perfect" window drifts on by.
I get it.
It can be a pisser.
But the "other side"... the not cautions one... is not one of frustration, it's one of very real danger.
Better to be frustrated than in a hospital, or worse.
No exaggeration... this is the fire that the "other side" is made of. Best not to play with it.
...for regular weekend types who enjoy flying in actual soaring conditions.
An inadvertent weak link break places a pilot at a competitive disadvantage...
I still won't tow people with doubled up weaklinks. You don't get to "make shit up". I don't "make shit up" for that matter either.
We all play by the same rules, or we don't play.
Morningside decided that they were happy with 200lb weaklink. They changed their tug's link and they don't just pass the stuff out either. If you'd like to know more about it... go ask them.
The law of the land at comps was 130lb greenspot or you don't tow. Seriously. It was announced before the comp that this would be the policy. Some guys went and made their case to the safety committee and were shut down. So yeah, sorry... suck it up.
The competition rules are established by Davis Straub whose unwavering concern for safety has always taken precedence over all other issues - including...
Davis Straub - 2011/08/28 15:26:28 UTC
Then again, Russell Brown had us double up behind him after six breaks in a row at Zapata. We couldn't figure out why we had so many breaks so quickly. Maybe just coincidence.
...allowing the gliders to get airborne.
Everybody plays by the same rules - a 350 pound glider flying two point uses the same Davis Link as two hundred pound glider flying one point. That way all gliders have the same:
- towline tension limit
- pitch and lockout protection
- probability of getting dumped
and there is no competitive disadvantage for anyone.
This ain't rocket science and...
Jim Rooney - 2011/08/25 04:55:25 UTC
It always amazes to hear know it all pilots arguing with the professional pilots.
I mean seriously, this is our job.
We do more tows in a day than they do in a month (year for most).
We *might* have an idea of how this stuff works.
They *might* do well to listen.
Not that they will, mind you... cuz they *know*.
Jim Rooney - 2011/08/25 21:40:25 UTC
Tommy.
First, I sent Steve a bunch of info offline. Hopefully it clears things up a bit for him.
Unfortunately, he's stumbled onto some of Tad's old rantings and got suckered in. So most of this was just the same old story of debunking Tad's lunacy... again .
See, the thing is... "we", the people that work at and run aerotow parks, have a long track record.
This stuff isn't new, and has been slowly refined over decades.
We have done quite literally hundreds of thousands of tows.
We know what we're doing.
...you MIGHT THINK these professional pilots with long track records have ideas about how this stuff works and know what they're doing - especially seeing as how if you think otherwise...
Jim Rooney - 2013/03/05 19:42:58 UTC
Again, tell me how all this nonsense is about "safety"?
So, a stronger weaklink allows you to achieve higher AOAs... but you see high AOAs coupled with a loss of power as *the* problem? So you want something that will allow you to achieve even higher AOAs?
Are you NUTS?
I'm tired of arguing with crazy.
As I said many times... there are those that listen with the intent of responding... you unfortunately are one.
You've done a great job of convincing me never to tow you.
Thank you for that.
Mission accomplished.
...you'll have an even harder time getting airborne.
...and can increase the chance of personal injury or damage to their glider--which is also a competitive disadvantage.
PURE UNADULTERATED ROT.
Jim Rooney - 2011/08/31 09:25:57 UTC
Oh how many times I have to hear this stuff.
I've had these exact same arguments for years and years and years.
Nothing about them changes except the new faces spouting them.
It's the same as arguing with the rookie suffering from intermediate syndrome.
They've already made up their mind and only hear that which supports their opinion.
Only later, when we're visiting them in the hospital can they begin to hear what we've told them all along.
Nobody's talking about 130lb weaklinks? (oh please)
Many reasons.
Couple of 'em for ya... they're manufactured, cheap and identifiable.
See, you don't get to hook up to my plane with whatever you please. Not only am I on the other end of that rope... and you have zero say in my safety margins... I have no desire what so ever to have a pilot smashing himself into the earth on my watch. So yeah, if you show up with some non-standard gear, I won't be towing you. Love it or leave it. I don't care.
So please, find me something... that you didn't make... that I can go out and buy from a store... that's rated and quality controlled... that fits your desire for a "non one size fits all" model, and *maybe* we can talk.
But you see... I'm the guy you've got to convince.
(or whoever your tug pilot may be... but we all tend to have a similar opinion about this)
You've not heard about strong-link incidents.
Uh, yeah... cuz we don't let you use them.
"light" weaklink issues?
"I had to land"... boo hoo.
Oh, I thought of an other one... I smashed into the earth after my weaklink let go cuz I fly as badly as I tow, and I'm only still here cuz my weaklink didn't let me pile in harder.
Your anecdotal opinion is supposed to sway me?
You forget, every tow flight you take requires a tug pilot... we see EVERY tow.
We know who the rockstars are and who the muppets are.
Do you have any idea how few of us there are?
You think we don't talk?
I'll take our opinion over yours any day of the week.
Ok, I'm tired of this.
I'm not really sure who you're trying to convince.
Again, I don't care to argue this stuff.
I'll answer actual questions if you're keen to actually hear the answers, but arguing with me? Really? Have fun with that.
Gimme a call when you think of something that we haven't already been through years ago... cuz to date, you have yet to come up with anything new. Well, maybe it's new to you I guess. It's old as dirt to me though.
"Light" weaklink issues? "I had to land."... Boo hoo.
Davis Straub - 2013/03/06 18:29:05 UTC
You know, after all this discussion I'm now convinced that it is a very good idea to treat the weaklink as a release, that that is exactly what we do when we have a weaklink on one side of a pro tow bridle. That that is exactly what has happened to me in a number of situations and that the whole business about a weaklink only for the glider not breaking isn't really the case nor a good idea for hang gliding.
I'm happy to have a relatively weak weaklink, and have never had a serious problem with the Greenspot 130, just an inconvenience now and then.
Davis has never had a serious problem with a Davis Link, just an inconvenience now and then.
If people at competitions were crashing and getting hurt then why is Davis still putting them up on 130 pound Greenspot which vaporizes...
...every time the tow runs into a minor thermal bump?
You cite me ONE SINGLE INCIDENT REPORT - USHGA, HPAC, BHPA, HGAF - from the entire thirty plus year history of Hewett based hang or para glider towing in which a light weak link has been cited as a contributory factor. If anyone had ever had a serious crash as a consequence of a light weak link vaporizing unnecessarily and dumping the glider into an unrecoverable stall don't you think there'd have been an immediate advisory circulated and that the leadership would've gotten as serious about enforcing legal minimums as it is about setting arbitrary maximums which put most gliders below legal minimums?
Dangerous situations arising from light weak link failures are purely mythological - they simply don't exist. People making the claim that they do are...
Donnell Hewett - 1980/12
Now I've heard the argument that "Weak links always break at the worst possible time, when the glider is climbing hard in a near stall situation," and that "More people have been injured because of a weak link than saved by one."
...simply ARGUING. And the argument they're making - that being on tow climbing hard away from the surface is somehow safer than being dumped off tow stalling towards the surface - is a really...
Jim Rooney - 2007/08/01 19:49:30 UTC
It's more of this crappy argument that being on tow is somehow safer than being off tow.
...crappy one. And God my head hurts. I'm so...
Jim Rooney - 2013/03/05 19:42:58 UTC
My god my head hurts.
Again, tell me how all this nonsense is about "safety"?
So, a stronger weaklink allows you to achieve higher AOAs... but you see high AOAs coupled with a loss of power as *the* problem? So you want something that will allow you to achieve even higher AOAs?
Are you NUTS?
I'll start with a legal review. The FAA has mandated requirements for weak links in FAR 91.309(a)(3) [ref 1] for civil aircraft towing sailplanes, ultralight gliders, and hang gliders in the US. It states:
(3) The towline used has a breaking strength not less than 80 percent of the maximum certificated operating weight of the glider or unpowered ultralight vehicle and not more than twice this operating weight. However, the towline used may have a breaking strength more than twice the maximum certificated operating weight of the glider or unpowered ultralight vehicle if--
(i) A safety link is installed at the point of attachment of the towline to the glider or unpowered ultralight vehicle with a breaking strength not less than 80 percent of the maximum certificated operating weight of the glider or unpowered ultralight vehicle and not greater than twice this operating weight.
and
(ii) A safety link is installed at the point of attachment of the towline to the towing aircraft with a breaking strength greater, but not more than 25 percent greater, than that of the safety link of the towed glider or unpowered ultralight vehicle end of the towline and not greater than twice the maximum certificated operating weight of the glider or unpowered ultralight vehicle.
Dr. Trisa Tilletti - 2012/06
I'll start with a legal review. The FAA has mandated requirements for weak links in FAR 91.309(a)(3) [ref 1] for civil aircraft towing sailplanes, ultralight gliders, and hang gliders in the US.
Wow! Really? When? Like a couple of weeks ago?
Shouldn't we have had some advance notice about this impending legislation so we could've pled our case for the special weak link requirements of hang gliders and had stricken that regulation for a minimum? I mean that MINIMUM is, for all intents and purposes, considerably HIGHER than our original 1985/07...
USHGA Aerotow Guidelines - 1985/07
USHGA Safety and Training Committee
II AEROTOWING EQUIPMENT
3) A weak link must be placed between the tow line and the release at both ends of the tow line with the forward link ten percent stronger than the rearward weak link. The weak link must have a breaking strength less than 85% the weight of the hang glider and pilot combination, not to exceed 200 pounds.
...MAXIMUM! And I never saw any problem with those regs. And nobody else did either - there was never a single word of objection in the magazine.
Lemme check Reference 1 to see if this is carved in granite yet. Maybe it's not too late to do something about this...
HOLY SHIT!!! This amendment went into effect 2004/07/27!!!
I'm Tracy Tillman, on the USHPA BOD, on the Tow Committe, and I am an Aviation Safety Counselor on the FAA Safety Team (FAAST) for the Detroit FSDO area. As a rep of both the USHPA and FAA, I would like to help you, USHPA, and the FAA improve safety in flying, towing, and hang gliding.
The FAA gets a lot of letters of complaint from a lot of yahoos...
...KNOW about this?! I mean Jesus H. Keeriste! If I check your Reference 4 it says:
Towing Aloft - 1998/01
For aerotowing operations, a weak link breaking strength equal to 80 to 100% of the total flying weight--the weight of the pilot and glider--is a reasonable starting point. This will typically be in the neighborhood of 200 to 250 pounds. With the common aerotow bridle that has a weak link at the end, about half these values is a proper weak link strength. A common weak link in this case is a loop of 130 lb test braided fishing line or a loop of 205 leech line with an overhand knot in it to weaken it. These weak links break around 120 lbs due to the knots and effect of rings or releases. When placed at the end of a V bridle it gives a tow breaking point of 240 pounds. This has also been evaluated experimentally by some experienced pilots towing to a high altitude and intentionally banking the glider up into a hard turn simulating a lockout to break the weak link.
240 POUNDS!!! That puts me at 0.75 Gs!!! I've been flying in violation of FAA regulations for nearly six years now! I thought that sucker was a bit flimsy and tried to up it but...
`
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 http://www.cortlandline.com/catalog/braid.html and should be placed at one end of a shoulder bridle. The tow forces on the weaklink will be roughly divided in half by this placement. Pilots will be shown how to tie the weaklink so that it more likely breaks at its rating breaking strength.
...at this year's World Record Encampment. I wonder if Rooney and Davis are reading the magazine as attentively as they should be.
But of course you've been being very careful to make sure your Cloud 9 students thoroughly understand and adhere to the regulations before signing them off on their AT ratings, RIGHT? And you can refer me to one of them who will affirm this - in court, under oath, under penalty of perjury, RIGHT?
How come Highland Aerosports didn't get the word on this? Giving them the benefit of the doubt and assuming that Glen is maxed out on his glider...
Gee Tad, Jim is just making sure nobody is going to rip off the tug's tail above Highland, they are kind of expensive, you know.
Brian, I don't know why you feel us bigger guys need to beef things up. Talked to Glen, he gave me permission to drop his name. He hooks to the tow line at an impressive 350 lb. He had a total of 1(!) unexpected weak link break out of all his tows. He knows nothing of this discussion, so I asked him how he felt about using a stronger weak link. His answer was a straight "NO". Both Glen and I veto you on beefing our weak links up based on our good and safe experience with greenspot.
...he's flying at 0.65 Gs. And NO, we're not gonna call it the 0.74 he'd have flying one point because until right after my letter to the FAA of 2009/10/27 there was a requirement that:
02. The towed vehicle (un-powered ultralight) must meet or exceed the Hang Glider manufacturers Association's Airworthiness Standards.
...and a glider being towed one point no way in hell meets - let alone exceeds - the Hang Glider manufacturers Association's Airworthiness Standards.
How come Greg Ludwig, the then Towing Committee Chairman, is asking...
Gregg Ludwig - 2009/02/12 00:05:51 UTC
Tad-
Would you be interested in a position on the ushpa Tow Committee? You can participate via e-mail if you can't make it to a BOD meeting. ..or just help me with a single project...
I need to rewrite the aerotow SOP...to include ATP and Sport pilot stuff....weaklinks...or just send me a proposal on weaklink sop ideas...
Gregg
Tow Committee Chair
...Yours Truly to help him rewrite the SOPs regarding weak links when the FAA had already rewritten them for us four and a half years prior to his request?
And sumpin' else...
The United States Hang Gliding and Paragliding Association, Inc. - 2011/11
12. Standard Operating Procedure
02. Pilot Proficiency System
12. Hang Gliding Aerotow Ratings
-C. USHPA Aerotow Equipment Guidelines
04. A weak link must be placed at both ends of the tow line. The weak link at the glider end must have a breaking strength that will break before the towline tension exceeds twice the weight of the hang glider pilot and glider combination. The weak link at the tow plane end of the towline should break with a towline tension approximately 100lbs. greater than the glider end.
Keep pushing your luck, motherfuckers. The next asshole you kill with a Rooney Link is likely to be heavy and in very clear violation of the 0.8 minimum limit and that's gonna open up some negligent homicide issues.
Dr. Trisa Tilletti - 2012/06
I'll start with a legal review.
Yeah, Trisa. You do that. With a bit of luck you might end with a legal review as well.
The sailplane guys have been doing this for a long time, and there are many hang glider pilots and quite a few tug pilots who don't understand what the sailplane guys have learned over the years. It certainly would help if hang glider towing methods and training were standardized to the degree that they are in the sailplane world.
Dr. Trisa Tilletti - 2012/06
Sailplane weak links rarely fail inadvertently--that's not so much the case for hang gliding weak links.
You and I have flown sailplanes for almost as long as we have flown hang gliders. We own two sailplanes and have two airplanes that we use for towing full-size sailplanes. In all the time that we have flown and towed sailplanes, we have not experienced or even seen a sailplane weak link break.
It's not that it doesn't happen, but it is a rare occurrence. Russell Brown, a founder of Quest Air in Florida and a well-known Dragonfly tug pilot, is also a sailplane pilot, tug pilot, and A&P mechanic for a large commercial sailplane towing operation in Florida. He told us that, like us, he has never seen a sailplane weak link break, either.
Jim Lee, two-time US Hang Gliding National Champion and six-time US comp point champion, was our commercial pilot sailplane instructor. He is a sailplane distributor, instructor, and tow pilot in Florida. He recently told us that he has only seen two sailplane weak link breaks, and experienced one himself, when he and the tow plane had to turn sharply on tow to avoid a helicopter that flew into their flight path. He said that his weak link performed properly in that situation.
Actually, that is our expectation of performance for weak links on hang gliders here at Cloud 9, too. Primarily, we want the weak link to fail as needed to protect the equipment, and not fail inadvertently or inconsistently. 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. It is the same expectation of performance that we have for the weak links we use for towing sailplanes.
So in the entire collective sailplane and sailplane tug driver careers of Dr. Trisa Tilletti 1, Dr. Trisa Tilletti 2, Russell Brown, and Jim Lee you've witnessed a total of two weak link breaks and experienced a total of one.
He recently told us that he has only seen two sailplane weak link breaks, and experienced one himself, when he and the tow plane had to turn sharply on tow to avoid a helicopter that flew into their flight path. He said that his weak link performed properly in that situation.
So neither you - a two-time US Hang Gliding National Champion and six-time US comp point champion; commercial pilot sailplane instructor for the great Drs. Trisa Tilletti 1 and Trisa Tilletti 2; sailplane distributor, instructor, and tow pilot in Florida; nor your tug pilot elected to abort the tow.
You elected to turn sharply ON tow to avoid the helicopter that flew into your flight path.
But then your polypro Pilot In Command stepped in and made the call to abort the tow. It PERFORMED PROPERLY because you and your driver were too stupid to realize that by continuing the tow you'd have ripped the glider apart. And, of course, if:
- you assholes had had to manuever hard to to avoid something at a hundred feet and your polypro Pilot In Command had PERFORMED PROPERLY by stepping in and making the call to abort the tow there's no fuckin' way you'd have stalled and cartwheeled on a tip
- for any reason - monster thermal, visible or invisible dust devil, visible or invisible dust devil, pilot error - your sailplane had been standing on its tail at a hundred and fifty feet and your polypro Pilot In Command had PERFORMED PROPERLY by stepping in and making the call to abort the tow there's no fuckin' way you'd have whipstalled back into the runway.
The most common emergency situations on takeoff develop when a towrope breaks, there is an inadvertent towrope release, or towplane loses power. There are five planning situations regarding in-motion towrope breaks, uncommanded release, or power loss of the towplane. While the best course of action depends on many variables, such as runway length, airport environment, and wind, all tow failures have one thing in common: the need to maintain control of the glider. Two possibilities are stalling the glider, or dragging a wingtip on the ground during a low altitude turn and cartwheeling the glider.
FUCK YOU.
- A weak link PERFORMS PROPERLY by breaking at its breaking strength and doesn't give a rat's ass about either:
-- the circumstances AT THE TIME it PERFORMS PROPERLY
-- what happens to the glider AFTER it PERFORMS PROPERLY
- So YOUR weak link PERFORMED PROPERLY in THAT situation. Meaning - OBVIOUSLY - that the two weak links you OBSERVED blowing performed IMPROPERLY in THOSE situations. So both of those breaks were unnecessary and undesired as well. And for all we know they could've resulted in kills - 'cause you're very conspicuously NOT saying why they happened and/or that they were nonevents.
So none of you motherfuckers has ever experienced or observed a sailplane situation requiring or improved by a weak link break.
So far I've only had negative experiences with weak links. One broke while aerotowing just as I was coming off the cart. Flared immediately and put my feet down only to find the cart still directly below me. My leg went through the two front parallel bars forcing me to let the glider drop onto the control frame in order to prevent my leg from being snapped.
All other weak link breaks have been during boat towing, and were uneventful and unwarranted.
Finally, while I understand that this is controversial, someone needs to explain to me just exactly how a weak-link makes towing paragliders safer for anything other than step towing. One of the most dangerous things I have witnessed is a weaklink break in the first thirty feet of a tow. THE REAL danger on a tow is a lockout, but a properly rated weaklink WILL NOT BREAK IN A LOCK-OUT (otherwise they should be impossible with regulated tow force systems like pay-out winches or hydralic winches, yet they are certainly possible on such systems).
If you have a system that regulates pressure, and an operator who is not asleep, what does a weaklink do except increase the chance that a momentary surge in tow force causes an inadvedent release close to the ground, right as you have gotten wacked?
I have towed hangliders for well over a decade, and EVERY SINGLE CLOSE CALL I HAVE EVER HAD WAS FROM A WEAKLINK BREAK. I have NEVER seen a weaklink "save" anyone from anything. When aerotowing, it is a must to protect the tug pilot, but even then I have known tug pilots (I am one) to release a glider too far out of whack much more often than the weak link does it for them.
Daniel Walker - 43911
- H4 - 1999/07/25 - Tracy Tillman - AT TFL TST CL FSL - TUG PILOT
- P4 - 2005/09/01 - Kenneth Munn - FL ST TFL TST CL FSL RLF RS TUR XC
So if we - sailplanes, hang gliders, paragliders - were all using ten thousand pound Spectra towlines as our weak links we'd all be better off.
Actually, that is our expectation of performance for weak links on hang gliders here at Cloud 9, too. Primarily, we want the weak link to fail as needed to protect the equipment...
So... if it's *only* purpose is to prevent your glider from breaking apart... which is complete and utter bullshit... but if that was it's only purpose... why then do we have them at all?
Your glider will tear the rope apart before it breaks.
It will tear the towmast off the tug before it breaks.
Your glider is capable of amazing feats of strength... it is in no danger of folding up on you.
...you've never been anywhere close to a situation in which you've NEEDED "the equipment" to be protected. You've just said that none of you motherfuckers has ever even seen a situation in which a weak link was needed to protect a sailplane and it would be close to physically impossible to tear a hang glider apart behind a Dragonfly.
...and not fail inadvertently...
ALL weak link failures are inadvertent - asshole.
...or inconsistently.
NO weak links fail inconsistently. They ALL fail precisely at their breaking strengths. And PRECISION doesn't matter AT ALL - regardless of what you're using or stupidly attempting to use a weak link for. If you shoot for somewhere in the top half of the legal range a fifty pounds one way or the other is very unlikely to make any difference.
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.
Donnell wanted his "Center of Mass" Bridle to autocorrect roll deviations. But he was - and IS - totally clueless regarding the physics of towing hang gliders as well.
And I'll bet Zack Marzec read your article 'cause that's EXACTLY what he wanted his Rooney Link to do. Unfortunately for him he hadn't paid much attention to its long track record.
It is the same expectation of performance that we have for the weak links we use for towing sailplanes.
Yeah? But seeing as you've never experienced or even witnessed a sailplane weak link blow and can only cite three in all the research you did for this fourteen page article - all of which were unnecessary, undesired, and potentially if not actually dangerous - just what is the fantasy on which you're basing your expectation?
