suspension

[Tad Eareckson]

http://www.hanggliding.org/viewtopic.php?t=28169
Maybe a stupid question about flying over water

Steve Seibel - 2013/01/31 00:12:24 UTC
Willamette Valley

One and a half years ago-- was in the surf-- maybe fairly mild surf but still surf-- and cold.

Was incredibly lucky that glider came to rest in an attitude near level, slightly nose-up, with nose out water, the sail over my head was not trapping me constantly under water and I could take several breaths, though my head was going under water frequently as the surf waves broke. So I didn't have to do everything on just the lungful of air that I had when I hit. I'm pretty sure I wouldn't have made it if that had been the case. The air trapped in the double surface helped the glider float.

I had trouble cutting my hang straps in the surf-- it was one of those deals where two hang straps, backup and main, are sewn into one double-thickness web. My hook knife choked on it. Due in part to the plastic housing flexing and opening up the gap between the blades as Steve noted.

Remind me when I get back to my glider stuff, to try cutting a remnant of that same strap with a fresh blade and report back how it worked. I don't think the blade was dull at the time but it was some years old, you never know.

Here's an idea, AEROEXPERIMENTS...

http://www.chgpa.org/forums/viewtopic.php?f=2&t=1079
$15 pacifiers

Jim Rooney - 2005/09/20 13:11:43 UTC

I know of at least one pilot out there that flies with two caribiners. His logic makes more sense to me... you can't have too many backups.

Try BREAKING a remnant of that same strap, compare the number you get to what it takes to rip your glider apart, and ask yourself how much sense it makes to have it backed up.

So I unhooked instead. It was NOT easy in the surf. Had just barely tightened the locking thing to the point where it started to overlap and prevent the gate from opening.

Here's another idea, AEROEXPERIMENTS...

Simulate an event which could cause an unlocked gate to open and ask yourself whether a locked gate is more likely to get you killed than keep you from getting killed.

Was glad I hadn't screwed it all the way. I never screw it all the way, there is no reason.

What's the reason to have it screwed part way? What's the reason to use a locking carabiner? 'Cause it LOOKS safer?

Also, here the two-straps-in-one was to my advantage, I only had one thing to unhook.

How 'bout one-strap-in-one?

Never give an "extra wrap" of the hang strap around the caribiner to shorten it, if you know what I mean-- that kind of mess would have been near impossible to unwrap in the surf. But then again maybe the hook knife would have cut it easy if just made of two single hang straps not a doubled one.

Still not hearing why you need two straps. How many times have heard about the primary breaking?

Put your hook knife on a line so you don't lose it but put a weak link on the line. I'm not kidding! After the hang strap was free, my hook knife wrapped around a flying wire and I almost couldn't get away from the glider. Which by now had floated over to near a shear cliff with stronger-breaking waves, and was about to be balled up I was sure. And I couldn't cut the line because I couldn't reach the knife. Finally I broke the line by pulling really hard but if you use a really strong line this might not work.

Use a velcro attachment if you plan on a lot of ocean landings.

Likewise a weak link on camera and everything else that is connected to you by a line. One could argue even for the harness zipper pulls...

Still flying with a Wallaby Release, bent pin backups, and a standard aerotow weak link?

When I finally got to the beach and got out, the glider was no longer visible. It had gotten balled up and sunk. Could have happened while I was still under it or still attached to it by that hook knife line, if things had gone a bit differently.

Stay in your harness, it floats. And keeps you warmer.

Land ANYWHERE but the surf.

[Tad Eareckson]

P.S. Steve...

- You spent a quarter of your projected life expectancy fucking with a hook knife that lotsa people - after drills and actual emergencies - KNEW had a low probability of being of any use.

- Your piece o' shit hook knife was rendered even more useless by the extra bulk of placebo webbing.

- Then you:
-- wasted some more time fucking with a carabiner locking mechanism that nobody's ever needed
-- almost got drowned anyway when the safety lanyard on one of your on the safety devices got hung up

And your response is to keep flying the same environment in the same configuration 'cept to use a breakaway on the primary safety device and in the same emergency situation hope for better results on everything else.

Yeah Steve...

http://www.chgpa.org/forums/viewtopic.php?f=2&t=1079
$15 pacifiers

Jim Rooney - 2005/09/20 13:11:43 UTC

I know of at least one pilot out there that flies with two caribiners. His logic makes more sense to me... you can't have too many backups.

http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?

Jim Rooney - 2011/09/02 23:09:12 UTC

Remember kids, always blame the equipment.

Really hard to go wrong throwing safety equipment into the equation - instead of engineering to do the job right.

[Tad Eareckson]

http://www.hanggliding.org/viewtopic.php?t=28169
Maybe a stupid question about flying over water

Scott (dscotts) - 2013/01/31 20:41:15 UTC
Portland, Oregon

Just north of here last year a pilot drowned his glider but escaped death himself. I asked him when he knew he was going in. He said "when the water hit my face".

Like most pilots, we think we can make it, we deny this is happening. He ended up trying to get his carabiner unlocked then switched to swimming out of his harness. Glider parts and four GoPros washed up on the beach three days later. No piece was longer than one foot.

Ya know, Wills Wing...

You...

Wills Wing

45B-9020
HOOK KNIFE ONLY
Harness Products
$22.50

...and/or your scummy dealerships are selling piece o' crap hook knives which have proven as useless in water landings as they are in towing.

You have stated the obvious - that there is NO engineering based reason to install backup loops on gliders and that the only reason you're doing it is as a cave to the idiot paranoias of your idiot customers.

You also ship your harnesses with overbuilt steel carabiners with locking mechanisms which also serve no useful function.

You know perfectly goddam well your gliders are gonna be flown over lakes, rivers, oceans, surf and that - given Murphy's Law and history - people WILL go down in the aforementioned and some of them WILL die.

So people are wasting critical seconds finding out the hook knives don't work before trying something else, if they have something that works they have to try to hack their ways through twice as much webbing as they should, and if they try to unhook they get slowed down or stopped by the locking mechanism.

Given enough water landings that piece 'o crap hook knife and those faux safety devices WILL kill somebody (if they haven't already). And I sure don't see you doing anything about it or participating in the discussions.

[JoeF]

http://www.youtube.com/watch?v=p1qe-XW_bR8

[Tad Eareckson]

http://www.hanggliding.org/viewtopic.php?t=28878
Coastal Flying - locked or not?

Coastal pilots - when flying how is your beener set up?

2013/04/26

number - percent

20 - 66 - Carabiner in both hang loops + carabiner locked
01 - 03 - Carabiner in 1 hang loop + carabiner locked
05 - 16 - Carabiner in both hang loops + carabiner unlocked
04 - 13 - Carabiner in 1 hang loop + carabiner unlocked

30 - Total Votes

Thirteen percent. Not bad. A lot more indication of intelligent life forms on The Jack Show than I'd have thought possible.

Janica Lee - 2013/04/22 13:45:22 UTC
Helix - California

When coasting flying, how is your beener set up?

Robert Moore - 2013/04/22 16:32:50 UTC

Get yourself a carabiner like the "Kong" style with a quick twist lock, and you won't have to worry about it. Local BA good-guy Steve Rodriguez sells them:

http://www.skypuppy.us/merchandise.htm

'Cause spinning a locking sleeve a quarter turn in the right direction and opening the gate is just as fast, easy, idiot-proof as opening the gate.

Tom Emery - 2013/04/22 16:51:28 UTC
San Diego

Cost

Weird post. Nice beener. Any idea what it costs?

- Thirty bucks.
- Who cares?

Definitely a better mousetrap.

- For addressing yet another nonexistent problem in hang gliding at the cost of adding ACTUAL problems? Like the one Joe found and identified in the previous post? Fer sure. (Nice catch, Joe. Thanks bigtime.)

- And this is the first time you've heard of autolocking carabiners?

Andy Long - 2013/04/22 17:04:47 UTC
California

I don't worry about my biner when flying near the ocean. That's because, through actual testing with hang gliders in the water, it has been found that you are better off putting your energies towards getting out of your harness rather than trying to unhook.

In ALL POSSIBLE SCENARIOS, right?

So, I've got a mental routine down that I would go through if I landed in the water. Step 1, step 2, etc. One good thing to practice is being able to unlock your chest and waist buckles without looking at them, with one hand only, etc, as that seems to be the biggest challenge.

The other one is radio wires that may be routed through your clothing that would still hold you underwater... even when you are out of your harness.

Scary sh%t Manerd... the thought of landing in the ocean/surf.

How 'bout THIS scenario:

Doug Hildreth - 1985/03

1984/03/03 - Garth Beatty - 28 - Intermediate - Marina, California - Pro-Star

Flying at beach with limited landing area (second flight on new glider). Misjudged and landed in surf in knee-deep water. Set glider down and unclipped. Surf flattened glider and, despite spectators trying to pull glider out, surf took glider and tangled pilot out to sea.

Any possible advantage to a nonlocking carabiner over:
- an autolocker?
- a screw locker?
- getting out of your harness?

But if you're a devout Aussie Methodist you needn't answer. I understand that your faith mandates that you only enter and exit the harness while it's hooked into your glider - no exceptions.

Jim Gaar - 2013/04/22 17:24:16 UTC

Hay RM I get nervous looking at that carabiner, then reading the info that talks about the webbing from your harness mains or parachute getting in the way of the gate. I fly with a LOT of pilots that also use a rubber band or inner tube section to keep the webbing in place on their carabiner.

With no tension on the carabiner it seems to me that getting it unhooked could be an issue! There's even a warning about it...

Idiot.

AndRand - 2013/04/22 17:43:01 UTC
Poland

According to some tests tight locking is required to prevent from fatigue strength failure. Putting things short - tight locking prevents tensions on carabiner due to clearance on lock (play on catch).

http://finsterwalder-charly.de/images/stories/startseite/downloads/karabinertest_april05_eng.pdf
http://finsterwalder-charly.de/images/stories/startseite/downloads/sicherheitscheck_karabiner_eng.pdf

Finsterwalder offers different construction carabiners or additional safety rope loops.

Has anybody run those fatigue tests on a carabiner suspended to a glider keel?

Don't we have anything better to worry about?

If you're worried about fatigue and not worried about separating from your glider real fast why don't you use a Speed Link:

http://www.flickr.com/photos/aerotowrelease/8322255878/

http://www.flickr.com/photos/aerotowrelease/8321197179/

like I do?

fly,surf,&ski - 2013/04/23 03:12:21 UTC
Torrey Pines

I did not answer the poll because for me it depends on what kind of coastal flying...

For dune gooning where you are flying Low and Slow right next to the surf and shore break, well then I go unlocked. Still going to do what ever I can (including piling in) to avoid the water, but IMO you are better off with the carabiner unlocked for dune gooning...

Tell me when a locked carabiner is EVER an advantage.

As for any other kind of coastal flying like Torrey or Funston I always lock the carabiner...

Why?

Rodger Hoyt - 2013/04/23 05:52:20 UTC

I always lock my biner.

I never had the slightest doubt.

It's part of a ritual of pre-flight muscle memory that I never want to deviate from regardless of the altitude I'm flying. "Sometime you lock, sometimes you don't?" Sounds like "sometimes you hook in, sometimes you don't."

Well, the really important thing is to NEVER - under ANY circumstances - do a hook-in check 'cause, as we all know very well, a hook-in check will...

http://www.rmhpa.org/messageboard/viewtopic.php?f=1&t=4258
HG accident in Vancouver

Tom Galvin - 2012/10/31 22:17:21 UTC

I don't teach lift and tug, as it gives a false sense of security.

...give you a false sense of security.

They used to sell a "quick release" carabiner that was designed with a pull pin to enable fast detachment from the wing in case of a water landing. Unfortunately there were too many unintentional "quick releases" in the air.

- Bullshit. They had a problem or two arising from webbing getting hooked over the T-handle on the pin but nobody ever separated from a glider in the air.

- They still sell a "quick release" carabiner designed with a pull pin to enable fast detachment from the wing. See:

http://finsterwalder-charly.de/images/stories/startseite/downloads/karabinertest_april05_eng.pdf

just referenced above. It's not mandatory to flush EVERY good idea that crops up down the toilet because Version 1.0 has a bug or two - even if this IS hang gliding.

fly,surf,&ski - 2013/04/23 17:49:50 UTC

"Sometime you lock, sometimes you don't?" Sounds like "sometimes you hook in, sometimes you don't."

Sorry, I just don't see the correlation...

The guy's an idiot.

Steve Seibel - 2013/04/24 17:17:08 UTC

unlocked

I unhooked while floating in waves two years ago. My harness would be difficult to bail out of due to fixed leg loops. Plus there's nothing like closed-cell foam for floatation and warmth in cold, active water.

I don't dispute that in violent surf or any time the pilot is completely and continually immersed and not able to take occasional breaths of air, bailing out of the harness might be better in many cases.

I leave my caribiner unlocked when flying near the ocean. Even over land I just twist the lock enough to overlap the gate by a small amount. There is no need for more, and you never know when you might have to unhook in strong wind, etc.

Tell me, AEROEXPERIMENTS... Why is there ANY need for a locked gate? (Idiot.)

If you want to standardize your procedure, just twist the lock enough to overlap the gate a small amount. Do that every time. It won't make it take much longer to unhook than if the lock were fully open, as long as you can keep "lefty loosey" straight in your head.

Yes. AS LONG AS you're functioning just fine under the terror you'll be experiencing with tons of churning water on your wing rapidly reducing you to aphid status.

If you ever land and notice that lock has moved enough that you can unhook without touching the lock, then you can start worrying about whether that procedure is really adequate. I bet it will NEVER happen.

How 'bout worrying about whether or not a locking mechanism has ANY impact on hang gliding that isn't TOTALLY NEGATIVE?

I can't imagine flying without a backup hang loop.

Of course you can't. You:
- put your Quallaby release lever on your downtube
- use bent pin backup releases on your shoulder
- use a Rooney Link as a lockout protector
- refuse to do hook-in checks
but there's no fuckin' way you're gonna fall out of your glider when that main fails.

But I would advise avoiding any arrangement that involves multiple wraps around the caribiner (to shorten the hang loop). That will really slow down your unhooking!

Yeah, but it might really speed up your ability to fly somebody else's glider.

Steve Seibel - 2013/04/24 17:28:18 UTC

http://finsterwalder-charly.de/images/stories/startseite/downloads/karabinertest_april05_eng.pdf
http://finsterwalder-charly.de/images/stories/startseite/downloads/sicherheitscheck_karabiner_eng.pdf

Interesting-- something to think about. I never heard that before.

Yeah Steve, keep thinking about that. The more people we can get focused on carabiner fatigue issues the sooner we can stop this all the carnage resulting from these things cracking apart in flight.

http://4.bp.blogspot.com/-bRrpHNa68iY/UQ6Pv9gRZyI/AAAAAAAAjTg/Hc22bx5122Q/s2048/20943781_BG1.jpg


Asshole.

[Tad Eareckson]

Skypuppy HangGliding
http://www.skypuppy.us/merchandise.htm

Safety note: Parachute bridle should be consolidated with harness mains to keep webbing clear of gate locking mechanism.

Good > < Not good

UNLESS...

Towing Aloft - 1998/01

Figure 7-21: Hooking Primary Release to Carabiner

Release lanyard looped through carabiner. Note: Carabiner faces backwards in this application to avoid loading gate and hinge improperly.

...you're using your carabiner as a two point aerotow release anchor. Then the big danger is that your Rooney Link will transmit so much force that if the gate's forward it will it'll blow the carabiner apart from the inside.

So you turn it around backwards and don't worry about the parachute bridle getting ripped to shreds as it's tearing up across the gate locking mechanism during a deployment.

DO try to do your homework and cover all the bases, Skypuppy.

(Fuck you Dennis, Bill, Peter.)

[Tad Eareckson]

Oops. I violated one of my fundamental rules and didn't assume the worst about somebody in hang gliding.

- The "Not good" configuration ain't all that bad. The parachute bridle is obviously aft of the harness suspension and WILL feed up the spine / WILL NOT get shredded on the locking sleeve.

- He has a stupid loop of climbing rope connecting the parachute bridle to the harness suspension to back up the connection "in case the carabiner fails".

Oh well, at least the photos don't depict a backup loop for the glider's suspension (although it's a real safe bet he has them on his gliders).

[Tad Eareckson]

http://www.hanggliding.org/viewtopic.php?t=29526
Carabiner

Brad Barkley - 2013/07/16 02:36:00 UTC

I'm flying with a harness I bought used, and having no problems with it. My instructor went over it when I got it and found it to be sound.

How did your instructor find your releases and weak link? No, wait. Your instructor is undoubtedly the one who set you up with and sold you your towing equipment - so it's undoubtedly top notch.

Lately, though, I've been thinking about the biner...

Of course you have. That's about the one piece of equipment someone with a brain the size of a walnut can imagine having a problem with.

...and how it would be hard to know if it had internal stresses in the metal, because I have no idea how much the PO might have dropped it on concrete, run over it accidently, etc. Pure paranoia, I'm sure...

Mostly. But don't discount the stupidity element - it's not like it was insignificant.

...but it's one of the few pieces of equipment without a redundant backup...

Right.
- If a port downtube, cross spar, inboard or outboard leading edge section, or sidewire blows there's another one just like it on the other side.
- And if your primary release on the keel fails you have a:
-- backup on your shoulder
-- Rooney Link - which has probably popped already
-- hook knife
-- professional tug pilot constantly poised to make a good decision in the interest of your safety

...and I'm thinking a new biner for the old harness might be cheap peace of mind.

For a cheap piece of mind? Hard to beat!

Question: which one?

Get the Omega Pacific Modified D 7/16" Steel Quik-Lok:
- 53 kiloNewtons
- close to twelve thousand pounds
- about four and a half times the strength of your Wills Wing Eagle 180
- over 35 Gs at max flying weight
- autolocks so it won't open up in flight and dump you
- easily unlocks and disconnects with one hand after you've broken your other arm by being three quarters of a second late on your flare timing

Ideas?

Yeah.

- If you're using it as a two point release anchor turn it around backwards so that the force transmitted by your Rooney Link doesn't blow the gate open.

- Use two of them, just in case.

http://www.chgpa.org/forums/viewtopic.php?f=2&t=1079
$15 pacifiers

Jim Rooney - 2005/09/20 13:11:43 UTC

Sorry, I don't see the logic in trying to save a couple bucks on equipment that I am litterally entrusting my life to. "Pacifier"? may be... but there's an old saying out there... "You never need the backup, until you need the backup".

I know of at least one pilot out there that flies with two caribiners. His logic makes more sense to me... you can't have too many backups.

You can't have too many backups - just ask Jim Keen-Intellect Rooney. And with twice as many carabiners...

The Press - 2006/03/15

The Civil Aviation Authority (CAA) is urgently pushing for new hang-gliding industry standards after learning a hang-gliding pilot who suffered serious injuries in a crash three weeks ago had not clipped himself on to the glider.

Extreme Air tandem gliding pilot James (Jim) Rooney safely clipped his passenger into the glider before departing from the Coronet Peak launch site, near Queenstown, CAA sports and recreation manager Rex Kenny said yesterday.

However, he took off without attaching himself.

In a video, he was seen to hold on to the glider for about fifty meters before hitting power lines.

Rooney and the passenger fell about fifteen meters to the ground.

...you're only half as likely to launch without connecting one.

Nic Welbourn - 2013/07/16 02:50:00 UTC
Canberra

If it's steel you'll likely be able to see if it's compromised (ie. it will be all smashed up). Not so for alloy.

Get yourself a new self locking STEEL carabiner.

Yeah, even though it would be obvious if there were anything wrong with it and there's obviously nothing wrong with it, buy a new one anyway. And keep flying your cheap bent pin releases 'cause everyone else does.

Mark Selner - 2013/07/16 02:50:29 UTC

If it's metal don't even give it a second thought.

Brad Barkley - 2013/07/16 03:08:18 UTC

Funny, in looking around I discovered that Wills Wing recommends replacing even steel biners every three to five years.

And whenever Wills Wing pulls a number out of its ass and publishes it you should do exactly what they say. When they tell you to use a loop of 130 pound Greenspot as your standard aerotow weak link, regardless of:
- your flying weight
- your glider's capacity
- whether your flying two or one point
- the fact that it:
-- puts you at two thirds of a G and way off the bottom end of the FAA legal range
-- just dumped, whipstalled, and killed a tandem aerotow instructor a lot lighter than you
you should do exactly what they say.

I wonder how many pilots never replace them.

If you do you'll be the first person in the entire history of hang gliding stupid enough to do it.

Notice that for their Falcon 3 Tandem flying at a commercial aerotow operation which is using the same carabiner while:
- carrying almost twice as much weight
- pulling aerobatics for the tourists about two out of three flights
- doing about a billion times as many launch and landing cycles as one of their typical muppet solos
the recommendation is also three to five years?

Lafe Williams - 2013/07/16 04:40:30 UTC
Tamworth, New South Wales

What's a biner worth $35-50?
Confidence in your equipment. Priceless.

The kind of fucking idiot who replaces:

- a twelve thousand pound carabiner every three to five years because some asshole told him to; and

http://www.hanggliding.org/viewtopic.php?t=29065
Cortland Greenspot source?

Brad Barkley - 2013/05/19 01:57:31 UTC

I thought of buying a roll of greenspot to make myself change my weaklinks more often.

- a two thirds G weak link every three to five flights because some asshole told him to

and thus feels confident about his equipment...

http://www.hanggliding.org/viewtopic.php?t=28727
Easiest sites to learn foot launch.

Brad Barkley - 2013/03/29 18:05:07 UTC

The tragic death of one pilot is no reason to dismiss an entire method of launch.

...has no fuckin' business flying anything and is just part of the malignancy destroying this sport. And ditto for anybody supporting this idiot replacing his carabiner to increase his confidence about his equipment.

[Tad Eareckson]

http://www.hanggliding.org/viewtopic.php?t=29526
Carabiner

Brad Barkley - 2013/07/16 05:28:40 UTC

Yes, I know... not aluminum, not mercury, not plastic, not J-B Weld, not Unobtanium. I want a steel biner to replace my steel biner. Yes and yes. I was just asking about particular brands or sizes (7/16, 1/2?)

you know...specific suggestions.

- Remove the carabiner that came with your harness and then put it back on. You will thus have replaced it and instead of being able to rip your keel apart just four times over it'll be able to rip your keel apart two to the second power times over - exponential dude.

- Use a half inch steel carabiner. 72 kiloNewtons. Over sixteen thousand pounds. Eight tons. You'll be able to pull 48 Gs and totally kick ass at any aerobatics competition you wanna enter.

- And be sure to keep flying the same Rooney Link that just killed Zack Marzec.
-- The tragic death of one pilot is no reason to dismiss an entire method of launch with a huge track record.
-- In hang gliding it's not cool to address actual and obvious threats - just totally lunatic imaginary ones.

Paul Walsh - 2013/07/16 05:58:31 UTC

AustriAlpin Delta Karabiner

This was probably the first steel karabiner to have been designed purely for hang gliding, and in my opinion nothing else is as good.

Search for it on net.

Use a fuckin' six dollar, three thousand pound, one inch Speed Link from Para Gear:

http://www.paragear.com/templates/parachutes.asp?group=244&parent=34&level=2

http://www.flickr.com/photos/aerotowrelease/8322255878/

http://www.flickr.com/photos/aerotowrelease/8321197179/

Tasi - 2013/07/16 07:55:50 UTC
Greece

Funny I was having this conversation just last night with somebody.

I believe there is another thread in here from some time ago with some good info; look it up.

To keep it short, don't even think of aluminum.

Bullshit. Paragliders use aluminum and I'd happily fly with a properly manufactured aluminum carabiner.

As others already said, they might be light and strong but a drop can compromise it with you noticing and failing in the air under load.

Bullshit. If that had any legitimacy there'd have been a one hundred percent increase in fatalities in the Seventies and early Eighties. But, in fact, there weren't any in-flight failures.

The way to go is a steel carabiner, from AustriAlpin with a breaking stress of 32kN, having a modified D shape to keep your straps clean and especially designed for hang gliders.

Use the fuckin' Speed Link.

Another alternative is the Stubai Super 5000. D shape with 50kN breaking stress.

I use the AustriAlpin for free flight and Stubai for FLPHG.

And I'll bet neither one has ever blown on you.

[Tad Eareckson]

http://www.hanggliding.org/viewtopic.php?t=29526
Carabiner

razola - 2013/07/16 19:26:03 UTC

I am an engineer but I don't know much.

An engineer who doesn't know much versus a hang glider driver who knows everything about everything by virtue of his vast experience. Breath of fresh air.

I think I am wrong but I don't understand why a climbing carabiner is safe to climb and unsafe for hang gliding. The loads when climbing are even higher because when the climber falls the carabiner is loaded dynamically. This carabiner in aluminium for example has allowable loads 5620 / 2248 / 1798 lbf = 25 / 10 / 8 kN (axial / transverse / open).

http://www.dmmclimbing.com/products/belay-master-2/

http://www.hitchnhike.co.uk/acatalog/dmm_belay_master_2_screw_lock_karabiner_a872_2009_big.jpg


As you know allowable load is a half when carabiner is loaded in transverse direction or open. I have loved this DMM carabiner because it is simple and avoid to be loaded in transverse direction.

- It's designed to be used with rope - not one inch flat webbing.

- If you stitch your harness suspension webbing to a bit of a snug fit on the carabiner it'll be impossible for the carabiner to accidentally rotate to minor axis.

- If your carabiner DOES rotate to minor axis it won't matter. The glider will still break before the carabiner does.

It is also easy to check immediately if it is open or closed.

You need to be doing that EVERY TIME you make the connection anyway. A couple of people have died as a result of partial hook-ins - and that's a pooch Yours Truly has screwed.

To practise climbing an aluminium carabiner is much more likely to receive impacts with rocks but the strength is considered to be enough. It is not so fragile!

And Brad's steel carabiner is even less fragile.

And also, aluminium is a material of aerospace industry. Aluminium is a material to fly, steel very uncommon.

In REAL aviation power failure on takeoff is very uncommon and considered to be a BAD thing.

I think the topic is about damage tolerance. But I think there is not really an issue with aluminium.

Correct. Get a good aluminum carabiner and don't abuse the crap out of it and you'll be fine.

I also think the critical load case for the carabiner should be a bad landing but the deformation of the structure during the crash should unload the carabiner.

It does.

There might be however a problem of abrasion because of the friction.

No.

But the carabiner should be inspected and changed if there is lost of material. I hope friction is not so high.

It isn't.

Can somebody refer to documented accidents due to an issue with an aluminium carabiner?

No. There aren't any. There HAVE been a couple of failures on the ground but there've been a good many sidewire failures in the air and resultant fatalities. But people are so much happier talking about the dangers of aluminum and used steel carabiners than they are doing preflight sidewire load tests and dealing with other issues that actually kill people.