If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Actual Rope Break
I had my first "rope break" ever today. I was approximately 200-250ft above the ground. Emergency procedures were not a problem.
The Tost released for some reason. Its a nose hook so the back release mechanism could not have been the culprit. Further testing with the wheel break on the ground revealed no problems so I took another tow and had no problems. The ring may not have been engaged properly (doubtful) or the slack I got in the rope was just too much when it tightened back up (probable but the release still should have held). In any case has anyone else ever experienced an actual emergency unplanned release? In 14 years of flying I have never heard of one. Good thing we do practice this. 2C |
#2
|
|||
|
|||
Actual Rope Break
At 23:20 01 June 2014, Kevin Christner wrote:
I had my first "rope break" ever today. I was approximately 200-250ft abov= e the ground. Emergency procedures were not a problem. The Tost released for some reason. Its a nose hook so the back release mec= hanism could not have been the culprit. Further testing with the wheel bre= ak on the ground revealed no problems so I took another tow and had no prob= lems. The ring may not have been engaged properly (doubtful) or the slack = I got in the rope was just too much when it tightened back up (probable but= the release still should have held). In any case has anyone else ever experienced an actual emergency unplanned = release? In 14 years of flying I have never heard of one. Good thing we d= o practice this. =20 2C Most common cause is a broken spring. If the spring breaks on one side it will still close the hook but with insufficient tension. This can cause intermittent failures. |
#3
|
|||
|
|||
Actual Rope Break
I've had rope breaks, weak link break, with slack line during training. At altitude so not an issue.
I have had ropes part on takeoff, normally at the initial strain on the takeoff acceleration, far up the rope, so it was missed on the first rope preflight of the day and failed late in the day. The glider hade barely moved 50ft, so it was not an issue. I've watched one ply of a three ply poly part about 50 ft in front of the glider. After I got off tow at altitude, I told the tow pilot he would need a new rope for the next tow. If your TOST released the ring, either it was not hooked up correctly, did it rattle after hooked up?, or your TOST springs are getting weak. Time to replace it. BillT |
#4
|
|||
|
|||
Actual Rope Break
Was the ring worn? If it isn't the full diameter it can self-release.
Jim |
#5
|
|||
|
|||
Actual Rope Break
On Sunday, June 1, 2014 5:20:14 PM UTC-6, Kevin Christner wrote:
I had my first "rope break" ever today. I was approximately 200-250ft above the ground. Emergency procedures were not a problem. The Tost released for some reason. Its a nose hook so the back release mechanism could not have been the culprit. Further testing with the wheel break on the ground revealed no problems so I took another tow and had no problems. The ring may not have been engaged properly (doubtful) or the slack I got in the rope was just too much when it tightened back up (probable but the release still should have held). In any case has anyone else ever experienced an actual emergency unplanned release? In 14 years of flying I have never heard of one. Good thing we do practice this. 2C I've had two uncommanded Tost releases myself and observed two more. (No drama ensued.) In another case, the hook wouldn't initially release until the pilot worked it loose by maneuvering the glider on tow. In all cases the release itself was found to be within its service life and in excellent condition with springs intact. The one common thing with all these incidents was a badly worn Tost ring pair. An abrasive runway had noticeably removed metal from the small ring leaving it with a rough, pitted surface. The point of the hooks "beak" could capture the rough ring against the cage with friction even though it wasn't fully inserted into the release. Even when tested by pulling hard on the rope, it sometimes wouldn't come loose but it could still work loose during the tow. The "beak" can't capture a new, smooth ring pair. We speculate the fail-to-release incident was the result on a worn, undersized ring getting cocked sideways inside the cage. If the tow operator can't be convinced to replace the ring pair, have the wing runner shake the rope to make sure it rattles in the hook after it is attached. If it's captured by friction, it won't rattle. |
#6
|
|||
|
|||
Actual Rope Break
when was the release mechanism last and most recently overhauled or
replaced? especially on old gliders teh release mechanisms were designed for the very old and obsolete old welded Tost double tow rings. (see the warning on Wings & Wheels website http://www.wingsandwheels.com/page30.htm and also on TOST website) when the current tow rings are used on these obsolete tow releases teh rings will not completely seat in the tow release so you are always left with a partially opened release waiting for the evental premature release... tim A0 "Kevin Christner" wrote in message ... I had my first "rope break" ever today. I was approximately 200-250ft above the ground. Emergency procedures were not a problem. The Tost released for some reason. Its a nose hook so the back release mechanism could not have been the culprit. Further testing with the wheel break on the ground revealed no problems so I took another tow and had no problems. The ring may not have been engaged properly (doubtful) or the slack I got in the rope was just too much when it tightened back up (probable but the release still should have held). In any case has anyone else ever experienced an actual emergency unplanned release? In 14 years of flying I have never heard of one. Good thing we do practice this. 2C |
#7
|
|||
|
|||
Actual Rope Break
Hi Kevin
Congratulations on managing this emergency safely. A low tow termination of the tow is a true emergency, that some people have not managed successfully, as discussed on this website. I've been gliding for a long time, and my experience is that unplanned tow terminations are very rare. I have only had two unplanned releases, the lowest at 400ft at Lasham (Euroglide 73), the other at 1000ft at Portmoak. On the one at Lasham, I was very aware that the entire competition grid were watching me. Both were wave-offs, due to towplane engine problems (neither serious as it turned out later, but the tow pilots were understandably concerned at the time). My experience seems logical when one considers that after liftoff, the tension on the rope should be close to the drag on the glider, i.e. about weight divided by L/D, i.e. about 35lbs or less. Apart from shocks from slack lines tightening, if the rope doesn't break during the first few seconds when the glider is being dragged over the ground, a 'pure rope break' is unlikely. The rope is essentially 'proof tested' in the first 30 seconds of every tow. I haven't had any ring or tow-mechanism malfunctions. So from my experience, the most likely (but rare) problem is a tow plane engine problem. You say you are pleased that you practiced for this. I assume you mean that you are glad you practiced 180 turns from 200ft. I wish to say that my personal opinion is that a verbal briefing (to go straight ahead) would have been much safer for your instructors to teach you, with a verbal briefing that any other alternatives must be delayed until high enough for 'some maneuvering'. I'd put that at 300ft minimum, when a 90 turn to look back, and do some thinking, would be be ok, but even then, a turn away to the safest area should be made, even if off-field. Otherwise, go more-or-less straight ahead, and let the insurance company worry about their glider. I'd recommend that instructors should teach that a low rope break is an emergency, and the only responsibility on the pilot is to get himself and his passenger down without harm. Damage to the glider should not be considered. I obviously don't know for sure, but I think its arguable that this teaching approach might produce more minor damage to gliders, but fewer fatalities. It's not that a typical glider isn't capable, aerodynamically-speaking, of performing a 180 at 200ft. They obviously can. Its that an early solo pilot may not be able to, and experienced pilots under that stress may not be able to either. Safety is a tricky concept. My view is that, to be safe, one should 'stop before it becomes unsafe'. That sounds obvious, but then consider that this logically means that we should 'stop while we are still safe'. Ie..... we should stop when we could have safely gone a bit further. The price for safety, is to stop too early. I can remember stopping flying (for weather) knowing people were thinking we could have safely gone on a bit longer. And they were completely right. Straining this logic, its arguably safer to teach to go straight ahead, even if an excellent pilot could do a 180. I stand by my remark made earlier, that a site where a straight- ahead landing is likely to produce more than minor damage, is not a safe site. At 23:20 01 June 2014, Kevin Christner wrote: I had my first "rope break" ever today. I was approximately 200- 250ft abov= e the ground. Emergency procedures were not a problem. The Tost released for some reason. Its a nose hook so the back release mec= hanism could not have been the culprit. Further testing with the wheel bre= ak on the ground revealed no problems so I took another tow and had no prob= lems. The ring may not have been engaged properly (doubtful) or the slack = I got in the rope was just too much when it tightened back up (probable but= the release still should have held). In any case has anyone else ever experienced an actual emergency unplanned = release? In 14 years of flying I have never heard of one. Good thing we d= o practice this. =20 2C |
#8
|
|||
|
|||
Actual Rope Break
On Monday, June 2, 2014 4:50:10 PM UTC+12, Andrew wrote:
My experience seems logical when one considers that after liftoff, the tension on the rope should be close to the drag on the glider, i.e. about weight divided by L/D, i.e. about 35lbs or less. No, that's not the case unless you're not climbing. With a tug flying at 65 knots and climbing at 6 knots (typical for our glass two seaters) somewhere around 9% of the weight of the glider (up to 600 kg or 1300 lb) is being borne by the rope. That's about 120 lbs in addition to the 35 lbs from drag. With a 300 kg all up single seater (PW5, Libelle etc) flying a bit slower and climbing at over 1000 fpm there is actually even more strain on the rope. I do agree that if it doesn't break on initial acceleration then it probably won't. I'm not going to go into the turn back or not question again other than to say if you can land safely more or less straight ahead then of course do so, but you should also be competent to turn back if that's best. |
#9
|
|||
|
|||
Actual Rope Break
Andrew,
thank you for your post. It helps to understand "why the rules are the way there are". On Monday, June 2, 2014 6:50:10 AM UTC+2, Andrew wrote: Hi Kevin Congratulations on managing this emergency safely. A low tow termination of the tow is a true emergency, that some people have not managed successfully, as discussed on this website. I've been gliding for a long time, and my experience is that unplanned tow terminations are very rare. I have only had two unplanned releases, the lowest at 400ft at Lasham (Euroglide 73), the other at 1000ft at Portmoak. On the one at Lasham, I was very aware that the entire competition grid were watching me. Both were wave-offs, due to towplane engine problems (neither serious as it turned out later, but the tow pilots were understandably concerned at the time). My experience seems logical when one considers that after liftoff, the tension on the rope should be close to the drag on the glider, i.e. about weight divided by L/D, i.e. about 35lbs or less. Apart from shocks from slack lines tightening, if the rope doesn't break during the first few seconds when the glider is being dragged over the ground, a 'pure rope break' is unlikely. The rope is essentially 'proof tested' in the first 30 seconds of every tow. I haven't had any ring or tow-mechanism malfunctions. So from my experience, the most likely (but rare) problem is a tow plane engine problem. You say you are pleased that you practiced for this. I assume you mean that you are glad you practiced 180 turns from 200ft. I wish to say that my personal opinion is that a verbal briefing (to go straight ahead) would have been much safer for your instructors to teach you, with a verbal briefing that any other alternatives must be delayed until high enough for 'some maneuvering'. I'd put that at 300ft minimum, when a 90 turn to look back, and do some thinking, would be be ok, but even then, a turn away to the safest area should be made, even if off-field. Otherwise, go more-or-less straight ahead, and let the insurance company worry about their glider. I'd recommend that instructors should teach that a low rope break is an emergency, and the only responsibility on the pilot is to get himself and his passenger down without harm. Damage to the glider should not be considered. I obviously don't know for sure, but I think its arguable that this teaching approach might produce more minor damage to gliders, but fewer fatalities. It's not that a typical glider isn't capable, aerodynamically-speaking, of performing a 180 at 200ft. They obviously can. Its that an early solo pilot may not be able to, and experienced pilots under that stress may not be able to either. Safety is a tricky concept. My view is that, to be safe, one should 'stop before it becomes unsafe'. That sounds obvious, but then consider that this logically means that we should 'stop while we are still safe'. Ie..... we should stop when we could have safely gone a bit further. The price for safety, is to stop too early. I can remember stopping flying (for weather) knowing people were thinking we could have safely gone on a bit longer. And they were completely right. Straining this logic, its arguably safer to teach to go straight ahead, even if an excellent pilot could do a 180. I stand by my remark made earlier, that a site where a straight- ahead landing is likely to produce more than minor damage, is not a safe site. At 23:20 01 June 2014, Kevin Christner wrote: I had my first "rope break" ever today. I was approximately 200- 250ft abov= e the ground. Emergency procedures were not a problem. The Tost released for some reason. Its a nose hook so the back release mec= hanism could not have been the culprit. Further testing with the wheel bre= ak on the ground revealed no problems so I took another tow and had no prob= lems. The ring may not have been engaged properly (doubtful) or the slack = I got in the rope was just too much when it tightened back up (probable but= the release still should have held). In any case has anyone else ever experienced an actual emergency unplanned = release? In 14 years of flying I have never heard of one. Good thing we d= o practice this. =20 2C |
#10
|
|||
|
|||
Actual Rope Break
At 23:20 01 June 2014, Kevin Christner wrote:
I had my first "rope break" ever today. I was approximately 200-250ft abov= e the ground. Emergency procedures were not a problem. The Tost released for some reason. Its a nose hook so the back release mec= hanism could not have been the culprit. Further testing with the wheel bre= ak on the ground revealed no problems so I took another tow and had no prob= lems. The ring may not have been engaged properly (doubtful) or the slack = I got in the rope was just too much when it tightened back up (probable but= the release still should have held). In any case has anyone else ever experienced an actual emergency unplanned = release? In 14 years of flying I have never heard of one. Good thing we d= o practice this. =20 I fly at a mainly winch launch site but perhaps fortunately originally learnt to fly at an aero-tow site. A few years ago whilst we had a tug on site I was giving a first ride in a Duo to a prospective syndicate partner behind a Super Cub. As we drew level with the winch, at the far end of the field with perhaps 300 yards of grass before a fairly high hedge, I saw the unusual sight of the tow rope snaking towards me. I guess our height was between 150-300 feet. I opted for a 360 degree turn and land on the grass behind the winch. To his credit my passenger never made a sound till after we stopped and yes he did buy a share!- The problem? The tug pilot had his map hanging on the release cord and found it restricted his view so pulled it off pulling the release in the process! He did buy me a beer that evening. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Rope Break! | Waveguru | Soaring | 9 | August 28th 12 03:17 AM |
Rope Break | Walt Connelly | Soaring | 4 | April 12th 11 09:04 PM |
Explanation Required: ATA (actual time of arr) and ATD (actual timeof dep) | SVCitian | General Aviation | 2 | September 19th 10 10:27 PM |
Actual Autos | Ol Shy & Bashful | Rotorcraft | 3 | April 26th 07 04:22 AM |
IR without actual IMC | Iain Wilson | Instrument Flight Rules | 26 | October 13th 03 11:26 PM |