Glider pilots: How often do you train your rope breaks?

[AlexUM]

Hi all!

To the glider pilots among you: After obtaining your license, how often do you train your rope break procedures?

I had a lot of simulated rope breaks during my training, either the instructor just pulled out, or the winch took the power out.

Once I got my license, I always try to get 2 to 3 rope breaks per season. And every time I'm flying somewhere other than my home base, I try to get a local instructor to get into the local procedure.

When I talk to other pilots, there doesn't seem to be consensus. More often than not, I get the feeling that people fly hoping that "it won't happen today".

I've witnessed one fatal accident due to poor procedure during a rope break, so from my point of view, you cannot train this enough.


PPRuNe-Gliders, what's your opinion about this?

[cats_five]

Each club has it's own formula. Mine does them as part of the formal check flights required, how often depends on what badge one has.

[flybymike]

Do they actually use "ropes?". Do glider pilots have "licences?"
Genuine questions.

[Tupperware Pilot]

Do they actually use "ropes?". Do glider pilots have "licences?"
Yes and yes....

[ProfChrisReed]

At my club, experienced pilots get an annual session of refresher training which includes launch failures. This seems entirely sensible to me, as modern winches rarely offer up a real failure and aerotow ropes hardly ever fail (if inspected regularly). New pilots begin with a regular check regime, and out of check pilots probably get a launch failure practice on their check flights.

Of course, if you are witnessed using poor launch technique then you will probably be invited to demonstrate the correct way to an instructor, as he or she has to write the accident reports if you can't cope with a real emergency.

I've witnessed a few real launch failures where the pilot didn't cope properly, and in all cases they were pilots about whom the instructors had concerns - pilots with poor decision-making, or over-confident pilots (often very experienced) pushing the envelope. Funnily enough, it tends to be these types of pilot who object to regular launch failure practice.

Annual practice seems to be enough for the rest of us to fly safely.

[mary meagher]

In my early days at Shenington, we had, on the winch, a reliable 50% SUCCESS rate, using piano wire. Sometimes we even had 3 cable breaks in a row. Certainly kept us on our toes and current; I still remember an enthusiastic launch in a K8, cable broke under strain, spaghetti all over the winch; only thing for me to do was to stay airbourne for a couple of hours and so avoid the telling off for pulling too hard!

Our late CFI, Paul Gibbs, rejoiced in keeping us current; seldom indeed on a check ride with PG did Blogs ever get to the top. As an instructor, I developed a similar vein of sadism; after a briefing on the things we would do after the launch, eg. stalls, spins, going for THAT cloud, etc etc, the sneaky hand on the yellow knob, and boing! Let's see what you can do with THAT problem!

Even more refined, brief the pilot on launch failures, then don't give him one.

[mary meagher]

Clarification to AlexUM, original poster, and to Tupperware pilot.

No, most clubs in the UK do not use 'rope! Braided steel cable is reliable, and unlike the Dynema rope used in some places, possibly on the Continent,
the braided steel cable does not lie on top of the grass, which causes a problem in clubs that do winch and aerotow, and do sometimes taxy across a cable, very carefully. We never never take off or land across a cable, if using a narrow run, the cables must be retracted before the airtow or motor glider departs.

[Crash one]

I seem to remember that rope was once tried at the club I flew from. it was left on the winch drum overnight after reeling it in & the tension cut the drum in half. No, they used to use 3mm piano wire now braided cable.
Using piano wire, several of us that were keen had a "repair kit" in the car.

[Tupperware Pilot]

No, most clubs in the UK do not use 'rope! Braided steel cable is reliable, and unlike the Dynema rope used in some places, possibly on the Continent,
On aerotow they do Mary.....you should know that..hehe

[Mechta]

Weak links work harden with use, which results in a well used one having a higher breaking strain than a fresh one. Its not unusual to have a weak link last months, only to then have two or three break replacements in quick succession, until one survives long enough to get enough launches to also be work hardened.

The Air Cadets had a policy at one time of giving pilots a new weak link for a first solo flight, which was just about the worst thing that one could do, as it would fail at a lower tension than the cadet and winch driver was used to on the previous launches.

[Crash one]

Weak links work harden with use, which results in a well used one having a higher breaking strain than a fresh one. Its not unusual to have a weak link last months, only to then have two or three break replacements in quick succession, until one survives long enough to get enough launches to also be work hardened.



Something lacking in the design department here. If they survive & become work hardened they are no longer the "weak" link they are supposed to be. How could one be re-calibrated to the next strength up? Prob impossible without breaking it to find out.
If weak links are designed like this then they are worthless, dangerous, chance of ripping the tow hook out of the glider. I would suggest some thought be put into them.
I believe they are just a short length of steel plate of varying thickness to suit the weight required. Bad idea.

[IFMU]

AlexUM,

Here in the states I only fly aerotow. In my 20ish years I have done about 5 simulated rope breaks, and two real ones, though one of the real ones I was in front of the rope. I was happy the real one was at harris hill, none of this 180 degree turn stuff, just head for the edge of the ridge and figure it out from there. On my day the ridge worked enough that I was able to climb and land back, else I would have landed at our emergency field.

IFMU

[Fitter2]

The odds against a rope break on aerotow are excellent - I've never had one in 50 years gliding. The odds against a towplane engine faliure (or some other serious problem) however are rather higher, and part of the pre-take off checks are 'what do I do if the tow terminates prematurely'. And a continual monitoring on the climb out of the same action plan.

Getting out of position in severe turbulence at some sites, in wave rotor, (and having to pull off) is always a distinct possibility, and that's again part of the action plan. Not happened so far, but I've come close.

Wire breaks on winch launching are rather more likely, and part of the annual proficiency check at the club where I fly. Again, a pre-take off plan taking wind, field layout and so on means that they are a non-event.

PPPPP

[mary meagher]

Hey, Tupperware, I think the original poster was referring to winching. It would be really peculiar to handle wire on airtow....though I am unfamiliar with those gadgets that retract the rope (?) after the glider lets go.....seems to me to add unnecessary complication, one more piece of machinery to fail, instead of occasionally dragging the tow rope through the hedge on return to the field. However, airfield supervision (the humble role to which I have been demoted since no medical any more) should ensure that the ignorant public, or for that matter ignorant pilots, should be kept well clear of the approach as getting dinged on the head by a flailing towline and steel rings is undesirable.

So, repeat after me. Braided steel wire for winching, Rope for aerotow. and keep it simple.

Reminiscing once again, regarding launch failure on aerotow; at Booker, High Wycombe, at about 200 feet behind the tug in a K13 back seat, suddenly we found ourselves pushing the rope. Tug went on without us.
I said - in a slightly elevated tone - "I have control!!" and turned to look at my options, which included being able just to slide in a handy corner of the airfield, so I ditched the rope (took 3 hours to find it later) and landed the glider back in the handy corner.

The student said "Why didn't you let me fly it? I could have done it!"

I replied "Well, I wasn't sure I could!!"

And again, from the other end of the rope, the 150 Supercub was not climbing at all well and the earth bank at the end of the short runway was fast getting closer, T's and P's OK, looked in the rear view mirror, and noticed the K13 had the airbrakes open! Scraped over the bank, climbed at about 45 mph IAS, and at 300 feet dumped the glider. All the second guessers told me I should have carried on....but my knees had turned to jelly. And the BGA rule says waggle the rudder to signal the glider that his airbrakes are open. Are you kidding? at 45 mph at 50 feet you think I'm going to wiggle the rudder? Oh yes.

The glider landed in a local field, no damage. But all three women aboard the combination have never forgotten that educational experience!

This is why we fly, to have adventures worth sharing in the bar.

I'm off to New Jersey on Thursday for the rest of August, so hasta la vista.

[BabyBear]

waggle the rudder to signal the glider that his airbrakes are open. Are you kidding?

Indeed! I have the same trouble when over speeding on the winch. I believe I am signalling the winch driver to slow down. My desire not to have the imminent bang happen when I am at 45 degrees with full rudder seems to overrule every time.

BB

[Prop swinger]

Something lacking in the design department here. If they survive & become work hardened they are no longer the "weak" link they are supposed to be. How could one be re-calibrated to the next strength up? Prob impossible without breaking it to find out.
If weak links are designed like this then they are worthless, dangerous, chance of ripping the tow hook out of the glider. I would suggest some thought be put into them.
I believe they are just a short length of steel plate of varying thickness to suit the weight required. Bad idea. Don't be ridiculous. There are hundreds of thousands of winch launches every year in Britain alone, I've never heard of a tow hook being ripped out of a glider. I know sweet FA about metallurgy but I'm sure that the manufacturers have taken such things into account.

Mary, some places do use rope on the winch. Skylaunch visited us a while ago to set up a winch for a continental club, equipped with a nylon rope. Also, from John Marriot's "Aerotowing Guidance Notes":
If the glider brakes are open, do not signal immediately unless absolutely necessary, try to get the glider to a safe height if possible, then signal.

[Crash one]

Quote:
Originally Posted by Crash one
Something lacking in the design department here. If they survive & become work hardened they are no longer the "weak" link they are supposed to be. How could one be re-calibrated to the next strength up? Prob impossible without breaking it to find out.
If weak links are designed like this then they are worthless, dangerous, chance of ripping the tow hook out of the glider. I would suggest some thought be put into them.
I believe they are just a short length of steel plate of varying thickness to suit the weight required. Bad idea.

Don't be ridiculous. There are hundreds of thousands of winch launches every year in Britain alone, I've never heard of a tow hook being ripped out of a glider. I know sweet FA about metallurgy but I'm sure that the manufacturers have taken such things into account.



I don't think I'm being ridiculous, OK so the hook might not get ripped out but the cable can break somehere else, or the glider could over speed & not feel the effect.
If the thing work hardens, & being an engineer I know that happens, then the thing is not the same as it was designed to be. Whatever the consequenses are.
So DID the designers take that into account?
Maybe gliders a stronger than they should be,. Either way I say again if something work hardens it is a piece of useless crap.
This is the same as replacing a fuse wirh a nail:ugh::ugh:

[flybymike]

Do glider pilots need a medical?

[BabyBear]

Yes, minimum as NPPL.

All about to change though, I believe.

BB

[flybymike]

Doubtless for the worse if EASA have anything remotely to do with it.

[BabyBear]

I believe so, though having the need for a Class 2, which covers gliding, I have not looked at the detail.

BB

[avturboy]

Many, many years ago I flew at Staffordshire Gliding Club when the club site was located at a place called Morridge (on the Stafforshire Moorlands near Leek)

The ground between the winch sites and launch sites was so poor (uneven and boggy) that normal cable recovery by tractor was near impossible so there was a retreive cable to haul the main cable back to the lauch site.

This also meant that a straight ahead landing from a low cable break was to be avoided at all cost. If memory serves correct the pre-flight mnemonic was CB SIT CB

C - Controls full and free movment
B - Brakes retracted and locked
S - Straps
I - Instruments
T - Trim
and ...
CB ... cable break ....

As I say we had very good reason not to want to experience a low straight ahead break, so the cable break consideration was drummed in from the outset, is this familiar to anyone else??

I've just worked out that that I've trawled back 37-38 years to remember this ... I'm not sure if it was the mnemonic that was so good or that the conseqences of getting it worng were so bad ... but I do remember it!

[Fitter2]

Actually the last CB was

Canopy locked
Brakes closed and locked

The first B was Ballast (cokpit load in limits, with fixed ballast added as required).

E (for eventualites) got tagged on the the end, for actions including, but not limited to, cable breaks.

[mary meagher]

Baby Bear, your commendable caution on undesirable attitudes when winch launching reminded me of my week of instructor completion under the wise guidance of Chris Rollings. Never, said he, let your glider while going up the wire assume an angle so steep that you would not be happy were the cable to break. Likewise, latest BGA advice, and this I agree with, is no longer to signal too fast, the glider is not stressed during the early part of the launch even if it is faster than comfortable. If things don't improve after half way up, just release and land (and communicate with the winch driver appropriately). As for signal "too slow", well, lower the nose, my dear, and if the winch driver doesn't get the message, time to release. They usually do get the message.

Here is a question I put to those who began gliding at a winch site, and wish to learn the aerotow:

Q. What is the most important difference between a winch launch and an airtow?

A. It is really difficult to kill a winch driver.

[BabyBear]

Never, said he, let your glider while going up the wire assume an angle so steep that you would not be happy were the cable to break.

Indeed Mary, in fact it is keeping it shallow for just a fraction too long that can result in an excess in speed which can then be impossible to lose irrespective of how far back the stick comes. All glider and conditions dependent of course.

BB

I speak as a novice with few solo flights in single seaters.

[funfly]

CB SIT SB...up slack...all out.
Wow memories... 1970 South Marsdon, I remember just making it over the bank in a K13 after my bronze C!
Instructor called Eric Winning, anyone know him?

[chrisN]

Just to correct two earlier answers:
No, there is no UK official (i.e. CAA or EASA) gliding licence. Under EASA, there will be but it is not yet here.

The BGA issues a licence upon request, but it has no official standing and is not obligatory for any level of flying, not even instructing.

Nor is there a legal requirement for a medical, AFAIK. The BGA has standards which have to be met by its member clubs and people who fly under their auspices, and AFAIK all BGA member clubs adhere to that or more, but there is no legal requirement for a club to belong to the BGA and any outside the BGA may not have that standard, or any standard, of medical. (And yes, there have often been, and may now be, one or more civilian gliding operations not in membership of the BGA. Again, under EASA, I think that may not be possible much longer.)


(By the way, my personal answer to the OP – several practice launch failures each year, usually. And occasionally a real one. Almost all winch, but I had one aerotow failure – rope came away from tug.)


Chris N.

[IFMU]

It would be really peculiar to handle wire on airtow....though I am unfamiliar with those gadgets that retract the rope (?) after the glider lets go.....seems to me to add unnecessary complication, one more piece of machinery to fail, instead of occasionally dragging the tow rope through the hedge on return to the field.

Mary,

We have those gadgets on all our towplanes. They have nylon rope. They are wonderful. I heard we got them at harris hill because we did score a glancing blow to somebody's head with a tow ring. Scary stuff, there. At the end of the field is a road, a parking area, and swings so people can look out over the valley. When the gadgets occasionally break, we have to use an old fixed rope. When I land over the people, I stay at least 200' high until I am at least 200' past them, then it is a pedal to the floor slip. We only have 1115' of pavement there, and some grass before. Not having to play those games makes the operation safer and more enjoyable, especially after a few hours of heavy towing, when fatigue starts to set in.

Some pictues of where the swings live are here:
Flying harris Hill (http://www.harrishillsoaring.org/www/PilotGuide.html)

Look where the road crosses in front of the field.

IFMU

[mary meagher]

IFMU, thank you for your reply, especially the attachment showing Harris Hill near Elmira - the very birthplace of American gliding, I am told!

Recommend all you guys have a look at it! Clearly the grid of 50+gliders is set up for a competition, probably a National comp? and probably at least 6 towplanes as well, to make sure the entire grid is launched in an hour - unless there are two classes, which makes life a little easier except that whichever class is launched last will get grumpy if they miss the best weather!

The cooperation in the US with local ATC for both gliders and GA is truly heartwarming, especially compared with the curious reluctance of the British to permit GA into controlled airpace....over here we are funneled into tight little corridors of free space. (OK, its a very small island, during the Olympics, even smaller, it seems..)

But for all that, gliding in the UK and in Europe is much more popular than in the US; we have to thank the Germans for that, as the restrictions on flying power during the 30's in that country caused accelerated development of sailplanes, and these days the truly hot ships in general production are still from Europe rather than the US. I bet most of the gliders in that photo of the grid on Harris Hill are European.....

Incidentally, good thing you have that extra airstrip available at the bottom of the hill....only way to keep a farmer sweet if gliders keep arriving is to buy a piece of his farm, and I bet he got a good price for it!

When planning your gliding club, my own personal theory is, it should not be at the top of the hill, like Long Mynd. Nor at the bottom of the hill, like Dunstable, but half way up the hill, like Talgarth (Black Mountains gliding club in Wales). Very very much worth a visit, all you sailplane pilots, for rock polishing, go to Wales.
Top of the hill attracts cloud cover. Bottom of the hill - hill gets too crowded, attracts hang gliders etc and sometimes fog from the valley delays
operations.

[BabyBear]

Nor is there a legal requirement for a medical, AFAIK.

Indeed, Chris, the medical standard similar to the NPPL requirement is in fact a BGA requirement, and not a legal one.

BB

[Prop swinger]

Crash One,

Add on the rest of Europe & there must be at least a million winch launches a year using these weak links, maybe 2 million. They are produced by an engineering company & I have no doubt that factors such as work hardening will have been taken into account during their design & manufacture.

[Crash one]

Then why suggeast that they break more easily when new than after work hardening?
They should be consistent. & I don't give a **** how many launches worldwide.
Consistency & designed to break at a particular tension is what they are designed for.
If "some" last longer after they are "worked in" that is, in my opinion rubbish. You cannot control the degree of work hardening except perhaps in laboratory conditions.

[Heston]

Work hardening involves permanent plastic deformation of the material. Do the weak links deform over time? That can't be a good plan in itself, apart from the implied variation of the breaking force.

What alloy are they made from? Almost all metal alloys exhibit some amount of work hardening, but whether or not it is significant will depend on what the material is.

H (once upon a time a metallurgist)

ps edited to add: this web site has details of weak links etc TOST TOW RELEASE (http://www.wingsandwheels.com/page30.htm) I note that the specified link breaking forces have a plus or minus 10% allowance, so the variation observed in use attributed to work hardening could still be within tolerance if the original as manufactured tolerances were much better than this. I'd expect the glider pilot and launch crew to notice a 10% increase in strength of the weak link, so maybe both sides of this argument are right. H

[davydine]

Crash One

A quick look at the load tables on the Tost web sites show that their range of weak links have a quoted breaking strain plus or minus 10% and they recommend that they are replaced after 200 launches.

This would suggest that up to 200 launches the link will break within its stated design parameters and thus the glider is not at risk

Home AGB Impressum (http://www.tost.de/ESollbruchstellen.html)

[Mechta]

Crash One wrote:

Something lacking in the design department here. If they survive & become work hardened they are no longer the "weak" link they are supposed to be. How could one be re-calibrated to the next strength up? Prob impossible without breaking it to find out.
If weak links are designed like this then they are worthless, dangerous, chance of ripping the tow hook out of the glider. I would suggest some thought be put into them.
I believe they are just a short length of steel plate of varying thickness to suit the weight required. Bad idea. The fact is that all materials have their own idiosyncrasies. Hang glider fliers often use a length of thin cord as a weak link when winching, but this can deteriorate with UV light, get chafed and the type of knot used can affect the failure load.

The properties of steel have been well researched, and the raw material is produced by very tightly controlled processes, so despite its tendency for work hardening, it is still a good material for the job.

A work hardened weak link will still be below its ultimate tensile strength, but perhaps 5 to 10% stronger than a new one. According to the table below, a black weak link of minimum strength (900daN) could work harden to 1100daN (22% increase) and still be in specification. Going the other way, launching on a weak link only 82% of the strength of the previous one is a good recipe for a cable break.

Once a weak link is taken beyond its ultimate tensile strength, necking will occur at the eventual failure point. If this is observed on an unbroken weak link, it is definitely time to change it as the load is now being transmitted through a smaller area. Tensile test and Stress-Strain Diagram [SubsTech] (http://www.substech.com/dokuwiki/doku.php?id=tensile_test_and_stress-strain_diagram)

With regard to breaking other bits of the glider or ripping the hook out, you need to compare the relative cross-sections of the components. The weak link has a very small cross-sectional area in comparison to the components in the glider and the winch cable.
Below are a selection of weak links and their breaking loads. Not all will be from the same thickness material, so some of the weaker ones may have smaller holes at the failure point than stronger ones.

What is very important is the surface finish on the walls of the centre hole (at which it is designed to fail). It must be reamed, as a drilled hole could fail over a much greater range of loads.

http://svsponline.co.uk/images/C/Weak%20Links%20%26%20Cable%20Accessories_1.jpg

http://www.svsp.co.uk/Shop%20Website/pages/Tost%20weak%20link%20chart%202.gif

Davydine, I would love to know how many clubs keep an accurate record of the number of launches that each weak link has done. Getting people to sign the winch daily inspection log is hard enough! :ugh:

[blind pew]

Yes there have been cases of winch hooks being pulled out.
My old club had two whilst I was a member - the second was a smelly French Side by side two seater.

Fortunately safety has increased in the UK.
Several years ago I penned a letter for S&G which started along the lines of accident.... Or culperable homicide .... after I read of two more avoidable deaths.
Of course I was ignored, so the letter was forwarded to a member of the executive who adopted the same stance as my club's chairman that the clubs which had a high accident rate would be forced by their insurance provider to change their operations.
The problems were centred around poor instruction and fear.
Fortunately someone in the BGA realised that we couldn't go on killing people and an excellent new guide to winch launching was published.
This dispelled many myths and restored my faith that there are intelligent people in flying who are willing to stick their necks out.
What we used to teach was to signal if you were too fast below 300ft - suicidal and also demonstrated a lack of knowledge of stresses and winching techniques.
Too fast and too much initial rotation to reduce over speeding.
Pole bending was derigeur.
And off course hanging on with a ridiculously low speed at the top of the launch.

I didn't understand winch launching until I had attended an ass cat course, instructed for six months and had a serious think about proceedures.
My last day running my old club I watched a trail lesson very nearly crash after a wing drop. My CFI ignored my complaint that it is unacceptable for a pilot to continue the launch with a wing tip on the ground.
Needless to say I quit the club.
Annual checks required several cable breaks which progressed to a low one around 400ft.
What wasn't done by some instructors was the bunny hop - because of the risks involved. The jury is out on that one as far as I am concerned - primarily as have carried out some extremely dangerous training exercises in my flying career which have now been discontinued.
In the states they have a stupid proceedure of getting the aero tow rope over the wing inflight...
And in france they do a return to ground whilst on aero tow.
Safe flying....

[mary meagher]

Hey, Blind Pew, your caveat has been recognised as correct; the latest word from the British Gliding Association is begin a winch launch with the left hand lightly holding the release....and if a wing drops - even before it touches the ground, RELEASE IMMEDIATELY. Which can prevent the painful possibility of a cartwheel, with fatal consequence.

Likewise, polebending is no longer considered sensible. See quote from Rollings on my previous post. Likewise, signaling too fast - also far more dangerous than accepting increased speed and departing the wire before the top of the launch.

Slow speed at the top of the launch....yes, time to leave, and also DON'T TURN until correct speed indicated on the ASI. Happier now?

I think that the wing drop problem is not the same on aerotow, if you have a nose hook on your glider, as the glider will usually straighten up OK once you get going. Ever land out in a field with nobody to hold the wingtip? the outcome is interesting: having been told by the tuggie to put THAT wing down before the launch, I did, and of course as soon as he increased power, the torque decided that the other wing looked better on the ground.. No problem, however, with a nosehook glider it all straightens out with no tendency to cartwheel.

Be interesting to hear from other glider pilots or tuggies on this question..

All the kerfluffle from the techies about differing breaking strengths of weak links...and the surprising information that a weak link gets STRONGER? with use? until it breaks, of course! I would say if the glider pilot relies on infalible weak links, he is seriously in need of launch failure practice, as recommended by the original poster.

Winch launches are spectacular, exciting, and can prove fatal. Yet a study of the points raised by Blind Pew, and eventually recognised as dangerous practice by the BGA, have resulted in recent years in the UK by far fewer horrible winch accidents. The only horrible thing I can think of now not covered by latest best practice, would be a hangup - which is rare indeed.
Anybody know about any hangups in the last 10 years? attributable to weak links getting stronger?

[davydine]

Mechta,

LOL, yes I can imagine, it's been a long time since I flew gliders but I am pretty sure that no one ever kept a track of how many launches a weak link did. Would be pretty hard given how often the link gets changed for a different colour when there are several different types of glider being launched.

On reflection I wonder how many weak links last as long as 200 launches and how many clubs routinely replace all of their weak links.

[Mechta]

Mary,

Winch launching accidents have reduced, but there is still room for improvement.

The emphasis to date has been on regular refresher training for pilots, teaching them to cope with cable breaks, wing drops and incorrect winch speed. The other person in the loop, the winch driver, should be the next point of focus. How many clubs really train their winch drivers to cope with the 'out of the ordinary' beyond a verbal description of what to do? Winches are quite capable of maiming and killing with or without a glider involved.

[MartinCh]

CBSIFTCBE
F - flaps (if applicable) haha. almost 40 years ago, not many flapped gliders around. Maybe except L13 Blaniks.

[blind pew]

Mechta
Whilst I wouldn't disagree with you as to correct winch driver training, my old club was excellent in that respect although there is always some room for improvement. (such as understanding that the launch can trigger a thermal and change the gliders airspeed).
But most of the drivers were fairly young. - the accident problem centred around some of the old f@rts who were instructing since Noah unloaded and were doing so for egotisitical reasons or for free flying to stay current over the winter.(their words).
Before anyone jumps down my throat I stopped instructing when I was in my late 50s as I had started making mistakes and wasn't giving money's worth.
Things go wrong very quickly on a winch launch.
I have known instructors in their late 70s who were excellent but I wasn't prepared to take the risk.

[Crash one]

Weak links work harden with use, which results in a well used one having a higher breaking strain than a fresh one. Its not unusual to have a weak link last months, only to then have two or three break replacements in quick succession, until one survives long enough to get enough launches to also be work hardened.

The Air Cadets had a policy at one time of giving pilots a new weak link for a first solo flight, which was just about the worst thing that one could do, as it would fail at a lower tension than the cadet and winch driver was used to on the previous launches.


If a weak link of a particular "spec" can be so different in service as to break readily when new & not break after work hardening to the point where it is so noticeable then the spec must be a bit wide!
As for ripping the hook out, I was being a little flippant:ugh: that is more likely to happen to aged wooden a/c possibly suffering from woodworm.
The more likely scenario would be a hangup & I was a member when that happened although didn't actually see it. Winch driver franticly whacking at piano wire over a piece of railway sleeper with a 7lb axe, glider doing tight circuits with 3ton winch hanging underneath. I designd & built a giulotine that cured that problem but was never used in anger. No doubt things are safer today than in days of yore & clubs routinely change weak links regularly, but how many new ones does it take till you find a "good" one?
The fact that gigamilions of launches take place successfully only proves that the release mechanism is an excellent design & a weak link is not required because pilots are not trying to pull the wings off.

[Mechta]

The fact that gigamilions of launches take place successfully only proves that the release mechanism is an excellent design & a weak link is not required because pilots are not trying to pull the wings off.

You are right that release hook design is excellent. It is not intended to release due to overload though, so the weak link is still an essential component. As Blind Pew pointed out, a thermal (or a gust for that matter) can suddenly increase the lift from the glider and the tension in the cable, before the pilot or winch driver can react to keep the tension in limits.

With winches typical putting 300hp+ into the cable drum these days, and their engines typically 30% efficient, there is 700hp of heat heading downwind to create, or at least accelerate, a thermal.

[ChrisJ800]

Cable breaks from a winch or car tow launch are pretty easy to land from (and we are well trained) but breaks during an aerotow when still low down can be tricky! Not much training in these so you need to think in advance what to do and consider a nearby field landing.

[LTCTerry]

I was home in the US in April - two lovely weeks with my family despite by dad being very ill. I took one day for myself and took the glider commercial written test in the morning and the checkride in the afternoon.

As part of the checkride the examiner did a simulated rope break right at 200'. I did an immediate 180-degree turn into the wind (over trees) at a 45-degree bank and continued another 45 degrees to intercept the runway. At this point my speed was slightly slower that I wanted (~57 instead of 60) and it was really hard to push the stick knowing that would give me speed instead of pulling "because I'm so low and need to stay up."

A 45-degree bank the opposite direction saw me lined up with the runway, brakes all the way out and as much slip as I could stand because I was still too high despite the 200' release.

I knew it was coming on one of the flights, so it wasn't a great surprise. I'd imagine it's different when unexpected. Hence, always expect a rope break on the winch and be ready to PUSH HARD NOW, accelerate, and fly the glider safely.

Terry

PS I've never had a real rope break on the winch, though I've seen several and done a number of simulated ones both in the UK and Germany.

[blind pew]

Generally a cable break on the winch is easier to handle if properly trained than one on an aero tow. Exception is the very low winch failure.
Problem created by a flat climb gradient without too many options.
The Montpellier club - made famous after having a collision with an airbus - has options of trees or grape vines verses turn and spin....not a joke especially during a downwind aero tow.

[longer ron]

Many years ago I was a member of a gliding club at a historic military airfield,the CFI decided I needed an annual check...fair enough :)
I was very current and had originally been well trained in cable break procedures LOL
First launch we get a real medium break...so 360 and land ...which of course I pay for...
Second launch we get a real medium cable break...so 360 and land...which of course I pay for...
Third launch we get yet another real medium cable break...but I just stuffed the nose down - pulled full airbrake (K13) and landed straight ahead,the instructor was a little confused as we had enough height for a 360...but understood when I told him that I did not have to pay for a straight ahead :ok:

[IFMU]

Cable breaks from a winch or car tow launch are pretty easy to land from (and we are well trained) but breaks during an aerotow when still low down can be tricky! Not much training in these so you need to think in advance what to do and consider a nearby field landing.

One thing I love about Harris Hill - my one real rope break (on the glider side) was at 20'. It was windy and we lifted off late, I think there was some local lift suppression on the runway. I just flew back down into ground effect and skimmed along until I was off the edge, then I had it made. The ridge even worked for a while, I climbed 700' until the wind direction swapped, lost 100', and made a normal landing. My oldest son has the broken weak link as a souvenir, which happens to be a work-hardened piece of nylon rope. Had the ridge not worked we would have had the emergency field, even the pawnee can make it there if the engine fails.

-- IFMU

[Fantome]

Our club in 30 years ops has never had an aerotow rope break or weak link failure. Look after the tackle and it will look after you.

[funfly]

I've looked after my tackle all my life but it still sometimes lets me down:O

[Doodlebug]

Herr AlexUM,

When I started it was car- and winch-launches only. We were regularly subjected to cable-break training. In addition to that there were frequent actual cable-breaks seeing as we used wire because our landing strips were invariably gravel or sand, i.e. very abrasive to more 'high-tech' braided lines. The wire was not as strong, of course, and did not take kindly to rough launches. As a result the general standard of flying in this kind of emergency was quite acceptable. I gather that cable-break training, also recurrent cable-break training, is still very much the norm when engaged in winch-launching. (anybody still attach themselves to a car these days?)

Nowadays with launching being predominantly aerotow (and self-launching of course) I see no more cable-break training, which is my answer. The question you posed makes me think whether we should be training aerotow cable-breaks? Or is the risk unacceptably great when weighed up against the statistical chance of an actual break occurring on tow? Certainly I would not be very happy practicing a cable-break at 50 feet AGL with the end of the runway just disappearing behind the tug and glider, and I'm not sure whether a simulated cable-break within the safety-circuit - once at a more reasonable height than immediately after lift-off - would have much benefit, seeing as how that scenario becomes just another circuit, albeit possibly a somewhat shortened version. What do the brethren think?

On an aside, I have a scar on one lower leg from a bit of wire that penetrated to a depth of around two centimetres from a winch-launch that went awry. One of those early-fifties beasties where one sat right atop the contraption, blissfully exposed to the action, only nominally 'protected' by a little canvas awning. When the cable broke the loose end would flail around off the drum, pieces sometimes flying off in all directions. The cacophony of sounds was a little unsettling, as well as occasionally being pierced by hot little pieces of wire. Nasty things, winches.

Was für 'ne Mühle fliegst Du? Hals- und Beinbruch!

[India Four Two]

I've looked after my tackle all my life but it still sometimes lets me downhttp://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/embarass.gif

funfly, unfortunately that becomes more common as we age! :E

[Krystal n chips]

" an immediate 180-degree turn into the wind (over trees) at a 45-degree bank and continued another 45 degrees to intercept the runway. At this point my speed was slightly slower that I wanted (~57 instead of 60) and it was really hard to push the stick knowing that would give me speed instead of pulling "because I'm so low and need to stay up."
As part of the checkride the examiner did a simulated rope break right at 200'. I did

I don't normally venture onto this forum, but the above doesn't quite make sense.

Surely you were being launched into wind ?....and the subsequent landing was downwind. You say you performed two 45 degree banks, which, from a height of 200 ft and descending after recovering airspeed from the "break" is pushing your luck a shade. And why, once you had the break and performed the 180 did you not simply land on the runway as I assume the tug had not deviated from the runway heading on departure given the height ( 200ft) of the simulated break.

As for cable breaks, well it's basic psychology and training to prepare for every launch with the potential in mind and keep the left hand very adjacent to the little yellow knob / handle.

The weak links have worked perfectly well over the years but there have been the odd times when the release hook has failed and thus the guillotine gets used on the winch.

[BackPacker]

Knc, I think he meant "into the crosswind". Furthermore, I think he was discussing a winch launch, where 200' is kinda tricky.

I just posted my exam paperwork for the GPL to the authorities, so I don't have a lot of experience in gliding, but IMO the bit between about 150' and 300' is the most tricky part on a winch launch. You don't really have enough altitude to do a proper, abbreviated circuit, you are already nose high so you need to shove the nose down quite hard before you have the proper glide attitude and visibility, and a lot of runway has already disappeared behind you, leaving you with very little room to land ahead. Landing downwind might be the only option indeed.

On the two aerotows I ever did, we only reached 200' when we were miles from the airfield. No way we could have made it back, but there were plenty emergency fields to choose from. I have not done the calculations but it seemed to me the ascent angle of a DA-20 with a fully loaded ASK-21 in tow is less than the descent angle of the fully loaded ASK-21 on its own. So unless the tug/glider combination somehow circles back to the field during the tow, there is no way the glider will make it back to the field in case of a rope break. Unless the glider manages to find lift somehow, of course.

Back to the original topic - my last simulated rope break was just last Monday. At the club where I learned gliding it's standard part of the checkout procedure. Normally done at 300', which is adequate, but not ample, for an abbreviated circuit.

[Mechta]

an immediate 180-degree turn into the wind (over trees) at a 45-degree bank and continued another 45 degrees to intercept the runway.

Surely you were being launched into wind ?....

I had to re-read that a few times as it didn't make sense to me initially, but he could be correct. There are some hilltop sites which due to the slope on them are take off downhill and land uphill runways, particularly when aerotowing. The one on Wasserkuppe springs to mind.

Having had an aerotow in which the tow rope just fell off the glider at 300ft, with nothing broken, I'm a great believer in not trusting anything.

The trouble with practicing practicing aerotow cable breaks is like practicing failure modes with winch drivers and low winh lauch cable breaks. If you practice it for real, sooner or later something's going to get broken. In other words, a good justification for a realistic simulator.

[IFMU]

an immediate 180-degree turn into the wind (over trees) at a 45-degree bank and continued another 45 degrees to intercept the runway.

We often have a crosswind at Harris Hill, and it is not possible to launch into the wind as the runway is much narrower than it is long. So when the rope breaks, you turn into the wind. One of the questions you should ask yourself as you prepare for launch, which way am I going to go if the rope breaks? Nothing Cory Lidle would understand but I hope the rest of us do.

There are some hilltop sites which due to the slope on them are take off downhill and land uphill runways, particularly when aerotowing.
Harris Hill is another of these sites. For us it is not so much about uphill vs downhill, but with only 1115' of pavement we only launch off the hill, and not toward the middle of it with its inhospitable terrain. When it gets to about 10 kts tailwind, we knock it off (which is yankee for we quit flying).

IFMU

[Krystal n chips]

" The one on Wasserkuppe springs to mind"

True :ok::)

However, and I am not being contentious here, some things still do not add up.

If it was a cable break, at 200 ft on a winch launch, then why not recover the airspeed ( always helps ! ) to approach speed, pull the brakes albeit only to a minimal extension, and land straight ahead ?....and if you have a cross wind ( and Bruggen for example, was notorious for such ) then you simply fly "into wind", then kick off the drift as per normal for landing.

Surely with a 200 ft cable break, there has to be more than enough landing area straight ahead even on short / narrow strips.

It would be nice to learn the type of glider and location therefore.

[Mechta]

KNC, LTCTerry does mention in the title that it was an aerotow, not a winch launch; so at 200 feet he may not have had much, if any runway in front of him. He also mentions in his later post that there was a downhill gradient to the runway, so he might easily have found himself going along in ground effect or rolling down the runway in a glider with little inclination to stop had he attempted to go straight ahead. Glider wheel brakes are notoriously bad, so he was wise not to try and rely on it.

[LTCTerry]

It was an aerotow, as mentioned in the title, but not clearly (OK, not at all) in the body of the text.

"Into the wind" - yes, actually into the crosswind component to reduce how far you travel from the runway.

180 degrees - only takes you parallel to the runway you just took off from - still need to get over the runway and straighten for a downwind landing.

It made perfect sense to me when I wrote it...

Terry

[chrisN]

Terry, I have no idea why anybody thought you referred to other than an aerotow launch, nor why they could not understand that a single turn (180 degrees?) gets you parallel to, not in line with, the runway for a downwind landing. Unless there is a cross wind which drifts you back in line , of course you need more than 180 degrees first, then an opposite turn to straighten up in line. What you wrote made perfect sense, as you said.

Re Bungey Launch, “The Midland Gliding Club is one of the few places left in the world where you can experience a Bungey Launch”. See:

Midland Gliding Club Ltd at the Long Mynd (http://www.longmynd.com/Album/index.htm)

ChrisN

[Krystal n chips]

" Terry, I have no idea why anybody thought you referred to other than an aerotow launch, nor why they could not understand that a single turn (180 degrees?) gets you parallel to, not in line with, the runway for a downwind landing.


Thank you for that condescending comment.It has a certain resonance that reminds me of the author of an accident report which began "during a low final turn, my left wing clipped standing corn".

Lets see then. Rope breaks around 200ft, you pull the cable release to jettison the attached rope, whilst recovering attitude and airspeed.

Assuming you are being towed straight ahead from the airfield, then a 180 (in the purest sense ) will result in you lining up parallel to the runway. However, during this "180" you will clearly see the runway thus you adjust the turn to line up with your intended landing area


The "180" is a metaphorical statement therefore as you state below.

Unless there is a cross wind which drifts you back in line , of course you need more than 180 degrees first, then an opposite turn to straighten up in line. What you wrote made perfect sense, as you said.

Is was the bit about a 180 "into wind" that confused my simple mind. This on the basis I have always launched into wind or a cross wind as the case may be.

Thank you, Terry, for your own reply though.:ok: