Carabiner and Mailion failures

[DavidG4]

51 minutes ago, AndyB said:

The one failure caused hard lock over at beyond normal maximum travel....and was on a 747-400 if my memory is correct (might not be).

Several B737 were lost due to uncommanded rudder hard-overs.  Aeroplanes are not steered by their rudders.  Rudder failure is not an issue, rudder hardcover IS.

 

As for using a loop rather than a caribina as a safety item, in PG some deaths have been caused by sudden stresses of one loop on another - heat is instantaneously generated and it  melts the fabric.  Not a good result.  I would prefer two carbines for sure.  Risk assessment, (not worry) - chances of failure...low. Result of a failure...catastrophic.   Answer...double up.

 

I used to fly a Mainair Flash but in the end the sight of just one main bolt stopped my flying - too much time in heavy metal with redundancy maybe, but I eventually couldnt hack it anymore.

[AndyB]

David, thanks. I have flown RC planes for 40 years so understand the controls rather well. When flying knife edge that rudder is all so important! And, yes, the 747 can't do that!...although one or 2 have tried on the way down.

I think the idea of a lightweight back-up for ppg (or pg) is something that would designing well. I had in mind a totally separate loop that attached to a different place from the main carabiner. Maybe wings would need to be made with a second lightweight attachment point for the 'reserve loop'. Even the speedbar attachment could done in a way that it could be the reserve.....if the risers were modified appropriately.

In the mean time this engineer checks his carabiners regularly and replaces them after 3 years or 100 hours. They don't cost much comparatively speaking.

[DavidG4]

Cheers Andy.  I always find it interesting that in a theatre the stage  lights are bolted to a pole which is suspended.  But the lights ALSO have a metal rope loop round them...just in case that well engineered bolt fails!  Likelihood...low, outcome...catastrophic.   Im with you.

[AndyB]

Interestingly, when my son was on stage in Peter Pan, a light fell off in the middle of a show and landed right next to him. Probably a 15 kg light. The bolts vibrate loose because of the 50 hz elec. The safety strap had not been connected! The show went on.

[geoffw]

Just my reasoning, you can easily pick up a ton bag of sand with a paraglider carabiner,done it ,!! and you can tow /move a large car with a A or B line done it,!!  All done with an old line and carabiner ,made me realise how much strength in built into our equipment give it a try yourself and see ,stop me worrying about line and carabiner failure. And always do your pre flight checks didn't stop me doing that.!!!!.

[HangTen]

You're probably referring to Northwest Airlines Flight 85.   That was a lower rudder hardover.

The actual "redundancy" in that case was the use of power adjustments from the engines and ailerons.   No injuries. System failures that would likely result in catastrophic loss of flight control generally have redundancies.

I sometimes use full rudder in combination with ailerons to do heavy cross wind landings.  Rudder controls yaw, ailerons control roll.  I had to practice those a LOT to get better at it.

If you figure out a way to avoid memory loss as you get older, please contact me 

[HangTen]

19 hours ago, geoffw said:

Just my reasoning, you can easily pick up a ton bag of sand with a paraglider carabiner,done it ,!! and you can tow /move a large car with a A or B line done it,!!  All done with an old line and carabiner ,made me realise how much strength in built into our equipment give it a try yourself and see ,stop me worrying about line and carabiner failure. And always do your pre flight checks didn't stop me doing that.!!!!.

Cool.  Good to know how strong they can be.  If the gate is neglected, defective or side loads occur, all bets are off.

Six Sigma is the BEST you can hope for.   And statistically, the absolute best is 3.4 (approx) failures per million.  REALLY low odds.   But again, that's the absolute best possible scenario, on paper.   it's probably not near that good in reality.    As far as odds go, I wish I could get those odds on Lotto tickets......I'd feel a win was actually possible.   So you can get a TON of near perfect carabiners......but at 500ft or less, just one bad one could be fatal.  And the fact is....like it or not, they're out there.   You "could" go your entire life and never encounter a bad one.  That said, don't worry about anything inside your own comfort zone.

Can you understand my point that of ALL the equipment on a PPG, the attachment point between the load and the lift is among the most critical?  especially since a failure of either one guarantees an instant jarring swing to one side and then a very rapid, very instant uncontrolled descent?

No one's "worried" about it......it's just a discussion.   Maybe some design in the future will incorporate 2 on each side.  Just for redundancy.

Here's some good info in another discussion

http://www.paraglidingforum.com/viewtopic.php?t=10346

Edited June 9, 2019 by HangTen

[HangTen]

Ok, so let me backtrack just a bit.......
After more reading (and learning), it would probably be more beneficial to find a way to never forget to secure your leg straps, than worry about a carabiner failure.

Seems that mistake (forgetting to secure leg straps)  is far easier to do and far more likely to get you than a carabiner.

This was just a discussion.  It's all good.

[AndyB]

I find always doing leg straps up first means they don't get forgotten. What I did do once was not have one latched properly, so it came undone when I took off. Not a great issue as you can still get into the seat by lifting yourself up on the risers. I now always give each clip a really good tug after doing them up. 

[HangTen]

Looky what I stumbled across......

A MUCH more authoritative summary of PPG Carabiners.

Don't use Aluminum ones seems to be the general advice.

[Steve]

32 minutes ago, AndyB said:

I find always doing leg straps up first means they don't get forgotten. What I did do once was not have one latched properly, so it came undone when I took off. Not a great issue as you can still get into the seat by lifting yourself up on the risers. I now always give each clip a really good tug after doing them up. 

Bad advice, lifting your weight on the risers - especially for new PPG pilots to read.

Seem to recall we've been here before. 

HangTen, I advise you not get too hung up on stuff until you've spent some time around experienced pilots and/or an instructor. Things like leg straps are the first thing you'll probably get drummed into you, it shouldn't ever be an issue. Paramotor flying is a joy and it's a case of understanding the risks, the equipment and your skill level - and flying accordingly. Do it properly and you'll love it. If you can, get yourself to a fly-in and immerse yourself in it all. 

[AndyB]

Steve just out of interest, what is a newcomer told to do if they have a leg strap failure and are hanging out of the harness? Having been in that situation it would have been nice to have been taught what to do. What is so bad about wrapping your hands around the risers just above the carabiners and lifting evenly with both arms at the same time? Doing this, then as far as the wing is concerned it knows no different.

[AndyB]

3 hours ago, HangTen said:

Looky what I stumbled across......

A MUCH more authoritative summary of PPG Carabiners.

Don't use Aluminum ones seems to be the general advice.

What?

[Patrick1]

43 minutes ago, AndyB said:

Steve just out of interest, what is a newcomer told to do if they have a leg strap failure and are hanging out of the harness?

My advice would be to close your eyes.

[Steve]

1 hour ago, AndyB said:

Steve just out of interest, what is a newcomer told to do if they have a leg strap failure and are hanging out of the harness? 

Leg strap issues should be picked up on preflight. Failure to do the straps up properly, as you did, is pilot error. Totally avoidable. 

[AndyB]

So your advice to a student whose leg strap comes loose is.....a) Close your eyes or b) It didn't happen!

Mine got a tiny bit of sand it. It looked like ti was done up and could even take a tug....but a big tug and out it came. Just takes a few grains of sand, which unfortunately is where I am most of the time. I have this same issue repeat a number of times now!!!!

[Trevsked]

Andy,

Good tip to check for grit/sand, easily missed I’d imagine.

 

Trevor.

[Patrick1]

I once had a belt buckle pop open high up over the Alps. As I was already back in the seat it wasn’t really an issue but it was a bit disconcerting. 

[AndyB]

Talking of sand, last week I had a single grain of sand stop my engine starting for half an hour. I eventually realised that the stop button on my throttle was still slightly pressed. It was jammed in with one grain of sand down the side between it and the housing.

[DavidG4]

On 6/9/2019 at 6:17 AM, HangTen said:

You're probably referring to Northwest Airlines Flight 85.   That was a lower rudder hardover.

There have been several. One was Singapore I think. Might be wrong 

On 6/9/2019 at 6:17 AM, HangTen said:

The actual "redundancy" in that case was the use of power adjustments from the engines and ailerons.   No injuries. System failures that would likely result in catastrophic loss of flight control generally have redundancies.

I sometimes use full rudder in combination with ailerons to do heavy cross wind landings. 

You don't mean heavy landings I hope.  Using full rudder and ailerons will give you a sideslip.  There are better cross wind techniques. You also do not need to always use full rudder.

 

Rudder controls yaw, ailerons control roll.  I had to practice those a LOT to get better at it.  

What can I say? 

If you figure out a way to avoid memory loss as you get older, please contact me 

 

[HangTen]

30 minutes ago, DavidG4 said:

You don't mean heavy landings I hope.  Using full rudder and ailerons will give you a sideslip.  There are better cross wind techniques. You also do not need to always use full rudder.

 

 Sideslip is exactly what a crosswind landing is.   You're "slipping Into" the wind coming from the side in order to stay on the runway center line. 

If wrong, by all means educate me before I hurt myself 

[AndyB]

Sometimes I crosswind land my paramotor using my head as a rudder.

[cas_whitmore]

Lol 

[DavidG4]

13 hours ago, HangTen said:

 Sideslip is exactly what a crosswind landing is.   You're "slipping Into" the wind coming from the side in order to stay on the runway center line. 

If wrong, by all means educate me before I hurt myself 

There are two techniques for crosswind landings...wingdown and crabbing. Crabbing is by far the easier.  Crab to the flair then kick off the crab just before touchdown. The aeroplane will fly exactly as you're used to all the way down.  

The other way is wing down...you fly a straight approach but One wing down (the into wind wing) so that the plane is always slipping  sideways but into wind so that the track over the ground is straight. In this technique you do not cross aileron and rudder.  This approach requires you to level the wings at some point but will allow you to touch One wheel first.  This approach means the aeroplane is never really level all the way down so its never quite 'normal' and thus may be more difficult. I'd use the crab.

 

Your sideslipping technique, using crossed rudder and ailerons, is wrong because thats not what a sideslip is for.  Sideslipping is a way of increasing sink rate in an aeroplane with no flaps, it is not a method for dealing with a crosswind.  It has the disadvantage in a crosswind of having crossed controls AND increased sink rate which, at the flair when you kick it off, dramatically reduces...so you float, and if you float in a strong crosswind you will float sideways.  

Definitely try to use a crab or wingdown technique for cross wind landings and keep the sideslipping for shortfield and for fun...which is certainly is.  Edit...just a thought.  Not all flapped aircraft are actually cleared for sideslipping. It puts quite a force on the fin and can blanket the controls.  Caveat emptor

 

Edited June 11, 2019 by DavidG4

[AndyB]

I really do find slide slipping my Roadster and using my head as a rudder works well. I just have to straighten my head when my feet touchdown. Admitidly, it can be difficult to see where I am going and this has resulted in some of my cross wind landing going off-course (well that's my excuse).