On Thursday, October 10, 2013 7:05:51 PM UTC+1, John Howell wrote:
So, given that it is alleged that the Germans have a far better record on
winch accidents than the UK, is there someone on here with a good knowledge
of UK and German practices to indicate where or indeed if there are
differences that might account for this.


We had this debate with Mr Daniels back in July where he was claiming that the UK winch accident record was an order of magnitude or more worse in the UK than Germany. He challenged people to look at the data, which I did (I think it was raining). My conclusion, reproduced below, was that the accident rates (based on fatalities and serious) were not currently significantly different. Having said that, I have no problem learning from what other people do - it's one way to get better. I'm a little disappointed, but perhaps not surprised, that Mr Daniels continues to broadcast the 10:1 difference.

Paul

Hi Bill

None of what follows is to gloss over the need to improve safety, or to say that we can’t learn from others. But, for those of us who have responsibilities in this area, it’s important to distinguish fact from opinion. You seem to be someone who thinks about these things, so here’s a real attempt to engage.

So far as I can tell, your premise is that the UK winch accident rate is very poor – an order of magnitude worse than the Germans, and that the cause of that is insufficient acceleration on launch. I think the facts show that you’re wrong.

Let’s unpack that.

GERMAN VS UK SAFETY
You said “The numbers I used are available for anybody to read and analyze. The differences are so huge, there's no way to come up with a different result. If you disagree, go read them and do your own analysis”. So I did and I have. My conclusion is that safety of winch launches in Germany is similar to that in the UK. I base this on the fact that a German pilot’s chance of being seriously injured or killed on a winch launch is similar to that of a UK pilot. I think the differences you are seeing are reporting and analysis differences.

In the last seven years, there have been 17 accidents with 20 fatalities and serious injuries closely related to winch launching in Germany. I’ve listed them below.

In the same period, there have been five fatal and serious injury accidents relating to winch launching in the UK. (see 2009-2012 accident reports by the BGA) so about a 3.4:1-4:1 ratio depending on whether you count accidents or fatalities. I’ve also listed those.

Given your earlier numbers of 180K launches in the UK, and 900K in Germany (a 5:1 ratio), the chance of someone being injured or killed on a winch launch in Germany looks pretty similar to that in the UK – certainly within statistical significance. I conclude that the safety of the two countries is probably similar (whilst still being very interested in anything we can learn from the way that the Germans go about things). We know we can improve in the UK – but it’s not helpful to suggest that there’s worse than an order of magnitude difference – it leads to looking in the wrong place.

Don Johnstone’s account of the way that the UK Air Cadets go about things Is much more compelling from an evidential point of view (no fatalities, similar numbers of launches to rest of UK, we’re told)

Why are your numbers so different? You seem to be taking the BGA numbers which are all accidents and incidents and comparing them with some fairly filtered results from Germany. The data you previously quoted from 2011, for example, and which you said were not filtered for serious and fatal are all on a table labelled “Reports on completed investigations of accidents and serious incident” from the BFU (http://tinyurl.com/occjw49). I don’t think they get to that list unless they’ve merited an investigation, and it’s notable that in earlier years (up to 2008) there were annual reports published with a lot of incidents that didn’t make it to the main list (see http://tinyurl.com/pxhm4ln).


CAUSE OF ACCIDENTS
If you’re talking about all the accidents and incidents that the BGA records (which is what you generally seem to be looking at), there’s little to support your contention that the speed of acceleration on the winch launch is the prime cause. By far the majority of incidents and accidents can in no way be related to launch acceleration – for example landing accidents following a real or practice cable break.

Even looking at the fatal and serious UK accidents, they appear mostly to be related to other causes.

I don’t think anyone is against the idea that an excessively long ground runs are bad – but it’s not clear that being told that the BGA advises a three second acceleration merits “You and the BGA are tragically wrong. You need to take another long look at that analysis. Slow acceleration is the most significant cause of the poor UK accident record. “ Even Andreas is saying that they use 3s accelerations at his club.

It’s also not persuasive to dismiss first-hand accounts as old wives’ tales. Think of the definition of the latter. At least one of the German accidents I looked at above seems to have been caused by a high acceleration pitch up (09-3X118) (subject to Google translate’s accuracy!). Even if you’re right about that, your correct observation that high accelerations can cause incorrect pitch sensations would seem to me to be quite a good reason to back off the acceleration. I don’t have a strong view or expertise on this, but I note there seems to be a degree of consensus around a 3 second acceleration (and when I looked at youtube videos, as you suggested, there was not a significant difference between UK and German practice – and I know how to time things, thanks).



Bottom line – there’s a useful discussion here, comparing practices in different countries. But it’s not helped by misunderstanding different data sets.

Paul

Here’s the data.

German winch accidents 2006-2012 (serious injury and fatal)

06-3X080: New solo student, cable break at 80m, turned, glider destroyed, serious injury
07-3X127: Steep climb, stall and flick at 40m, glider destroyed, fatal
08-3X041: ASH 26 E, stall and flick at 20-30m, aircraft destroyed, serious injury
08-3X063: Discus 2, water, launch from wing stand, wing drop or low altitude stall, aircraft destroyed, serious injury
08-3X113 : Hornet, roll at about 30m, stall? Aircraft destroyed, fatal
09-3X047: DG300, Low cable break, turned, spun in, glider destroyed, fatal
09-3X118: Cirrus. High acceleration, high angle, flick, aircraft destroyed, fatal
09-3X123: Climb to 10-20m, dropped a wing, crash, injury
09-3X144 : Janus, cable break, heavy landing, one serious injury
10-3X058: SF34, Low cable break, turned, spun in. Aircraft destroyed, two fatalities
10-3X059: ASW19, hit ground from 10-20m. Aircraft destroyed, serious injury
11-3X060. : A Jeans-Astir got launched into a Remos ultralight which crossed the pass of the glider from right to left. The two a/c's collided in about 1,200ft and both lost their wings resulting in three fatalities.
11-3X065: The glider was launched on the winch but did not gain sufficient altitude and released in about 40m. Instead of landing straight ahead, the pilot tried to reach a field to the left and then forced the glider into a ground-loop. Pilot suffered broken vertebrae; the passenger only minor injuries.
11-3X080: A LS4 was being launched and after 40-50m of ground roll (!!) the gear collapsed. The glider was dragged for another 23m on the belly and finally lifted off. The launch-boss had given the 'All-stop' command which was followed by the operator. The glider did not have enough speed or altitude to recover and landed very hard. Minor injuries
11-3X093: Spin-in after normal launch - aircaft destroyed, fatal
11-3X095: A Ka-8 was launched on the winch and when the glider's right wing touched the ground and veered off to the right, the launch-boss gave the command 'All stop', which was followed by the operator. The the command to continue the launch was given but the line detached from the glider which then stalled over the right wing and impacted the ground out of about 10m. The pilot was 65 years old. Serious damage and injury
12-3X034: Wing drop, serious injury, aircraft destroyed

I missed out a couple that were on a winch but were, for example, controls not connected.

UK winch accidents 2006-2012 (serious injury and fatal)

2006-2008: 2 fatal or serious injury accidents connected with winch launching (BGA Glider Accidents in 2008)
2009: Cable break at 300 ft, instructor lowered nose, turned, stalled. Serious injury
2009: Stall and flick during rotation. Fatal
2012: Cartwheel after wing drop. Fatal