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 |
#21
|
|||
|
|||
Wing Launch - Can it pull your wings off?
Bob Kuykendall wrote:
Breaks should be totally routine and pilots should handle them instinctively. I'm sorry, Bill, I'm still not buying it. It's the word "never" that rings my bell. I stand by my words: A rope break shall *never* be hazardous as such. Of course, every pilot may screw up, but that's a completely different question and not limited to rope breaks. |
#22
|
|||
|
|||
Wing Launch - Can it pull your wings off?
Derek C wrote:
The site in question is a narrow strip 800 metres long, sloping downhill at about 1 in 10, on top of a hill and totally surrounded by small unlandable vineyards. They always launched downhill, irrespective of wind direction. Once above about 200ft, but below circuit height, the only cable break option to get back onto site was a 180 degree turn (teardrop circuit) to land back uphill. And where's the problem? |
#23
|
|||
|
|||
Wing Launch - Can it pull your wings off?
On Aug 15, 2:23*pm, Bob Whelan wrote:
Are there folks winch launching from postage-stamp-sized-fields surrounded by unlandable terrain using a beyond-the-boundary-winch? The site where I converted to winch launching was like that. It's "Jury Hill", at Greytown, near Wellington NZ. There is a quite long north/south runway, but the interesting conditions are often in westerly winds. The westerly runway starts from the southern end of the main runway and at the time I was flying there had a length of around 300 - 400 m. The winch run was something like 1200 m with the remainder of the distance to the winch crossing a mixture of swamp and low "sand dunes" (not actually sand, but similarly lumpy). The cable retrieve vehicle used a not terribly straight path through the lumps, including crossing a farm track and one or two small streams. With a glider with good brakes (e.g. Ka7, ASK13) and a bit of a headwind (and you wouldn't use that runway unless there was too much crosswind for the other one) you could land straight ahead from a cable break at 200 or 250 ft and make some kind of circuit from 200 ft or less, so there was always either one good option or else two reasonable ones for the same runway, plus the option of simply turning right 90 degrees onto the 1000+ m runway and land with a crosswind. |
#24
|
|||
|
|||
Wing Launch - Can it pull your wings off?
Bias disclaimer -
I learned to fly on a winch. First two flights in gliders were aerotow - Never took an aero tow again until 3 years post solo. So you might say I have a primacy bias towards winch feeling right and consequently perceived as safe. That said - The BGA statistics, taken from the UK and continental Europe, unfortunately are unequivocal that winch launching was responsible for a disproportionate number of fatalities. Note I said disproportionate - so corrected for the relatively higher percentage of winch launches. Having run a formal program to remove unsafe practices and to understand the dynamics of what happens when it goes wrong, the recent statistics are very good. It turns out that winch launching IS actually very safe as long as best practice is followed. AND as long as everyone involved - including the winch driver knows what to do. So - anyone who considers a launch failure to be an emergency, is in need of some "upskilling" it should be "ops-normal". But, to say that a cable break is never dangerous is denial. Any cable break involves danger - handling it correctly should be standard unexciting practice - but denial of risk is the most dangerous thing in flying... For me - there are few things more stressful in all my glider flying that being dragged at low level by some anaemic tug - full of water - over the "select a hazard of your choice - rocks, shacks, water, trees, power lines..." Conversely - winch launching lets you get into trouble VERY quickly. Whichever way you launch , there is no substitute for awareness and having a plan for what to do if things go wrong. For my part - If I have to chose a launch emergency I would far rather have the winch failure - you generally have more alternatives for mitigating that risk. Bruce On 2010/08/15 6:22 AM, Bob Kuykendall wrote: On Aug 14, 3:43 pm, wrote: Bob, John Smith is correct. If a cable break appears hazardous for a particular pilot, then that pilot is seriously under-trained. Almost 90% of winch training is directed to safely handling rope breaks and a good winch instructor just won't sign a pilot off until a safe outcome is assured. Note that I said "rope" since steel cable is no longer insurable in the US. Snip --- news://freenews.netfront.net/ - complaints: --- |
#25
|
|||
|
|||
Wing Launch - Can it pull your wings off?
"The BGA statistics, taken from the UK and continental Europe, unfortunately are unequivocal that winch launching was responsible for a disproportionate number of fatalities" BGA statistics on Continental Europe are seriously in error. You're just trying to say that everybody else is a bad as the UK - they aren't. I have obtained accident statistics from Germany for 2009. More than 1.5 million winch launches resulted in just 17 accidents (13 of which were really landing accidents since the glider was in a position for a safe landing with good height and airspeed.) There were three fatalities. That's an absolutely extraordinary safety record - far, far better than aero tow in the US or winch launch in the UK. The SSF says the US lost 12 people on aero tow in 2009. If winch launch is done competently, as it is in Germany, it's orders of magnitude safer than aero tow as practiced in the US. I strongly advise adopting the training methods and operating techniques used in Germany. John Smith's point is not about the infallibility of pilots, (fools will find a way) it's that a winch operation should never put a pilot in a situation where more than basic flying ability is required to recover from a rope break. This goes for aero tow operations as well. As an instructor, I can tell if a pilot has to think through a recovery or is doing it instinctively. I train until it's instinctive. If they maintain that level of competency, rope breaks will never be a hazard for them. |
#26
|
|||
|
|||
Wing Launch - Can it pull your wings off?
On Aug 14, 6:37 pm, bildan wrote:
Every E&R Experimental operations limitations letter I've seen requires operation in compliance with the AFM. I can find no such requirement in mine. Does anyone else operating experimental (racing/exhibition) have this requirement in their operating limitations? If so, would you please email me a copy. FAR Part 91.9(a) requires operation in compliance with an AFM if one is part of the original airworthiness certification. (i.e JAR-22) My operating limitations do not require compliance with all of part 91. They reference very specific sections. In reference to 91.9 they state in para 21 - This aircraft shall contain the placards., markings, etc. required by 91.9. 91.9 (a) states a) Except as provided in paragraph (d) of this section, no person may operate a civil aircraft without complying with the operating limitations specified in the approved Airplane or Rotorcraft Flight Manual, markings, and placards, or as otherwise prescribed by the certificating authority of the country of registry. It is my interpretation that "or as otherwise prescribed by the certificating authority of the country of registry" means that the details of the operating limitations specified by FAA (the certificating authority in the country of registry) take precedence. Those operating limitations make specific reference to the requirement for placards and markings but make no reference to the AFM. Why would the operating limitations pick out specific sections of part 91, and specific data from the AFM, for inclusion unless only those included references/restrictions were applicable? It would be far simpler to state that the aircraft is required to operate in accordance with Part 91. I'm very sure (based on FAA interpretations) if an E&R airworthiness certificate is issued for a glider which had a standard airworthiness certificate with AFM in it's country of origin, the mere issuance of a US E&R airworthiness certificate does not excuse the owner of the glider from compliance with the AFM. Can you please give me references to, or email copies of, any interpretation that requires compliance with the AFM when the operating limitations do not. Do those interpretations also relate to compliance with an approved maintenance manual? thanks Andy |
#27
|
|||
|
|||
Wing Launch - Can it pull your wings off?
On Sun, 15 Aug 2010 07:34:22 -0700, bildan wrote:
As an instructor, I can tell if a pilot has to think through a recovery or is doing it instinctively. As a pilot, one never knows whether one will get to the top of a winch launch. During my training, at HUSBOS, simulated cable breaks were very much in evidence. Recovery does become instinctive, and rather fun. -- Alex |
#28
|
|||
|
|||
Wing Launch - Can it pull your wings off?
The debate on the merits and technicalities of winch launching will
rage on ad infinitum as it has for years in the winch newsgroups. However, in terms of winch safety the statistics for the UK and Germany are very different. Winch launching on the Continent shows a much lower accident rate than the British experience. In other cases a mishandling of statistics paints an out-of-focus picture. For example an article published in Soaring magazine a while back quoted statistics from a very small sample group to make a point about winch safety. The article was very much off-base and was a poor piece of work based on insufficient data. The German study, however, does appropriately apply statistical analysis to an appropriate sample size. I am surprised that no one has asked the question: Is it sensible to winch launch a 50-year old wooden glider, in which the type has had reported structural issues? A quick look at the UK winch accident records seems to involve a disproportionate number of old gliders and marginal winch equipment. Having flown at winch operations in both the UK and Germany, my limited experience has been that the Germans (generally speaking) are operating with better equipment than may be the case in the UK. (Yes, of course there are some operations in the UK with all the latest stuff and good procedures. But on the grand average maybe not as good as on the Continent.) So when the original question is asked, the first context should be – Really? Winch launching 50-year old wood wing gliders? Bob |
#29
|
|||
|
|||
Wing Launch - Can it pull your wings off?
On Aug 15, 5:03*pm, RL wrote:
The debate on the merits and technicalities of winch launching will rage on ad infinitum as it has for years in the winch newsgroups. However, in terms of winch safety the statistics for the UK and Germany are very different. Winch launching on the Continent shows a much lower accident rate than the British experience. In other cases a mishandling of statistics paints an out-of-focus picture. For example an article published in Soaring magazine a while back quoted statistics from a very small sample group to make a point about winch safety. The article was very much off-base and was a poor piece of work based on insufficient data. *The German study, however, does appropriately apply statistical analysis to an appropriate sample size. I am surprised that no one has asked the question: Is it sensible to winch launch a 50-year old wooden glider, in which the type has had reported structural issues? * A quick look at the UK winch accident records seems to involve a disproportionate number of old gliders and marginal winch equipment. Having flown at winch operations in both the UK and Germany, my limited experience has been that the Germans (generally speaking) are operating with better equipment than may be the case in the UK. (Yes, of course there are some operations in the UK with all the latest stuff and good procedures. But on the grand average maybe not as good as on the Continent.) So when the original question is asked, the first context should be – Really? Winch launching 50-year old wood wing gliders? Bob If gliders are not capable of being winch launched using the correct weak link, they are not airworthy. We winch launch vintage gliders all the time in the UK as part of a very active Vintage Glider movement. Derek C |
#30
|
|||
|
|||
Wing Launch - Can it pull your wings off?
The debate on the merits and technicalities of winch launching will
rage on ad infinitum as it has for years in the winch newsgroups. However, in terms of winch safety the statistics for the UK and Germany are very different. Winch launching on the Continent shows a much lower accident rate than the British experience. In other cases a mishandling of statistics paints an out-of-focus picture. For example an article published in Soaring magazine a while back quoted statistics from a very small sample group to make a point about winch safety. The article was very much off-base and was a poor piece of work based on insufficient data. *The German study, however, does appropriately apply statistical analysis to an appropriate sample size. Glad you brought this up, I also didn't like that article. My main problem was less the sample data size, but rather the timeframe it represented. It lumps all the statistics going back to the 60s into single figures when it should really be separated into at least 2 or 3 different 'eras' for that same timeframe, when various gliding authorities and groups identified common problems and implemented standardized solutions that were game changers. Also, modern winches are orders of magnitude more powerful and more importantly quite controllable. That combined with material advances (UHMW etc) further separate modern winching from it's roots. Modern winching is pretty much a science and has come a long way since the 60s so it does not do the soaring community (US at least...) a favor to combine it all into single raw statistics cause it paints a negative biased picture based on irrelevant data. It would be like combining accident data from the era before seatbelts and airbags with modern car accident statistical data, and then using that to form statistics/articles to help potential future drivers decide how safe cars are. -Paul |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
physics question about pull ups | John Rivers | Soaring | 59 | June 10th 10 12:21 PM |
FS: Wings&Wheels Wing Stand | James Hamilton[_2_] | Soaring | 0 | September 12th 09 01:15 AM |
Pull up a chair and hear me out: | Vaughn | Aviation Marketplace | 0 | February 2nd 06 02:04 AM |
Better GPS, Flight Computer, Variable Wing Geometry, abililty to Self-Launch | Stewart Kissel | Soaring | 7 | May 2nd 05 06:02 PM |
Glider pull-up and ballast | M B | Soaring | 0 | September 15th 03 06:29 PM |