Super Dimona accident

On Sep 8, 4:12*pm, Gary Evans wrote:
On Sep 8, 11:05*am, Ramy wrote:





On Sep 8, 9:23*am, Greg Arnold wrote:

On 9/8/2011 8:54 AM, Renny wrote:

On Sep 8, 7:44 am, JJ *wrote:
The NTSB just reported a Super Dimona crashed in the pattern at
Winsted, MN on 5Sept. 1 dead, 1 injured. Anybody got any more info on
this?
Does that make 8 this year?
Sad,
JJ

JJ,
Sadly, *this appears to be the 9th glider or motorglider related
fatality of the year in the US.....
Renny

Don't we have close to 10 fatalities in a typical year, so this year is
about average?

Assuming that there are 5000 active pilots in the US, that gives a
typical pilot a 1/500 chance of getting killed each year, or about 20
times higher than the chance of getting killed in an auto crash.

Average is around 6-7 per year. At this rate we will break 10 before
the year ends!
1/500 chance per year, makes it 1/20 chance in 25 years! This sounds
about right when you look at how many old time pilots are still
around... This is really sad.

Ramy- Hide quoted text -

- Show quoted text -

Does this mean we can't use the "safer than driving to the airport"
anymore?

Over the past thirty years, I have lost two friends from car
accidents, two from suicide, and four from hang
gliding/soaring. Not enough to stop p me soaring!

Mike

On Sep 8, 2:12*pm, Gary Evans wrote:

Does this mean we can't use the "safer than driving to the airport"
anymore?

My apologies in advance if I am taking that question more seriously
than intended.

It might have been true in the 1950s when there were a fraction of the
cars that there are now, but about 50,000 people were dying on US
highways every year. But I think that today it is very far from the
case, and has been for a while. Here's an interesting chart of road
deaths per mile; it shows the steep decline through the last 90 years:

http://www.thetruthaboutcars.com/201...ties-declined/

It would be interesting to put together corresponding charts for
glider flying. However, the individual metrics of hours, miles, and
flight cycles would probably not tell the whole story. It would take
several charts to compare fatalities with hours of exposure and cycles
of exposure for different types of flying (training, local flights,
cross-country, competition) to get a good picture of what is going on.
And my understanding is that it is hard to get reliable metrics for
numbers of cycles and hours; it is not something that is tracked well.

What I generally tell people is that flying gliders is about as
dangerous as riding motorcycles. The comparison is actually not all
that good, but it is in the ballpark on several levels and is the best
thing that comes easily to hand.

Thanks, Bob K.

On Sep 8, 2:33*pm, Jim Britton wrote:
On 9/8/2011 8:54 AM, Renny wrote:

On Sep 8, 7:44 am, JJ *wrote:
The NTSB just reported a Super Dimona crashed in the pattern at
Winsted, MN on 5Sept. 1 dead, 1 injured. Anybody got any more info on
this?
Does that make 8 this year?
Sad,
JJ

JJ,
Sadly, *this appears to be the 9th glider or motorglider related
fatality of the year in the US.....
Renny

-

If you include the 2 Canadians I coundt12 now.
You all seem to have missed the dead tow-pilot.

Jim

Jim,
I had not heard about the tow pilot fatality. Can you tell me where
and when this accident occurred? Sadly this year is really turning out
worse than anyone even knew....
Thanks - Renny

On Sep 9, 6:05*am, Ramy wrote:
Average is around 6-7 per year. At this rate we will break 10 before
the year ends!

With such a small expected value the standard deviation is very high
compared to the average.

In a Poisson distribution, the standard deviation is the square root
of the mean, which would be about 2.5 in this case. So, over 20 years
you'd expect to see 1-2 deaths in some year, and 10-11 in some other
year, just from purely random chance. (and, no, it's not
symmetrical .. 15 is a lot more likely than -2)

Assuming that the distribution is binomial or hypergeometric would
give much the same result with more complicated math :-)

(hypergeometric is the best theoretical ft to the situation, as it
allows for the facts both that the population is relatively small and
a given person can die only once. Binomial is a little simpler to work
with and is correct for things that can happen more than once to the
same person. Poisson is even simpler math and is the limit of both
binomial and hypergeometric for a very large population size and small
probability)


1/500 chance per year, makes it 1/20 chance in 25 years! This sounds
about right when you look at how many old time pilots are still
around... This is really sad.

Maybe my club is not typical somehow, but by that measure we should
have had about 5 gliding-related deaths in the 25 years I've been a
member, but there have in fact been zero.

Our club size seems to vary from about 80 members to 120. The *active*
members is I guess around 40, depending on what you call active. There
are ten or so regularly rostered tow pilots and a similar number of
instructors, and there are currently 18 on the "ground controller"
roster.

What accidents have we had? Well, that I can recall:

2010: Cirrus failed to make it back to the airport in heavy sink,
landed on the street breaking glider wing on a pole. Pilot uninjured.

2005: overseas visitor landed club's Std Libelle in a rocky riverbed.
Insurance writeoff. Pilot uninjured.

2005ish: contest outlanding failed to make the selected field (spin?).
Glider repaired. I *think* the pilot suffered a broken leg. Our club
member but flying at a club 500 km away.

1993ish: Blanik following Janus failed to make it back to the field,
landed on the main highway at about 4 pm on Easter Monday. Avoided
cars, wingtip hit a steel pole, severing wingtip and snapping rear
fuselage. Pilot uninjured.


I can't think of any others since I joined the club in 1985.

Our long time chief tow pilot died flying a small twin engined plane
on a commercial passenger service in the Pacific islands. A visiting
summer tow pilot from France later died in a crop duster in Africa.
And we've lost quite a few members to cancer or old age.

I'm sure that any of the four incidents I listed above could have lead
to death. But they didn't, fortunately.

Equally, I'm sure there are dozens of near misses that could have led
to serious damage and injury but didn't.

Every flight is dangerous so I guess the best course is to look at the
actual outcomes, not "gosh that was lucky!"s.

On Thu, 8 Sep 2011 14:12:56 -0700 (PDT), Gary Evans
wrote:

.... text deleted


Does this mean we can't use the "safer than driving to the airport"
anymore?

I realize Gary may not be wholly serious in this comment, but for
those newer to the sport, Bruno Gantenbrink's 1993 talk on this
precise topic should be of interest to all of us. Our sport is
tragically unforgiving of those who fail to take it's risks seriously.

DG has been kind enough to archive Bruno's lecture on their site.

http://www.dg-flugzeugbau.de/safety-comes-first-e.html

Bob

On Sep 8, 6:17*pm, Renny wrote:
On Sep 8, 2:33*pm, Jim Britton wrote:





On 9/8/2011 8:54 AM, Renny wrote:

On Sep 8, 7:44 am, JJ *wrote:
The NTSB just reported a Super Dimona crashed in the pattern at
Winsted, MN on 5Sept. 1 dead, 1 injured. Anybody got any more info on
this?
Does that make 8 this year?
Sad,
JJ

JJ,
Sadly, *this appears to be the 9th glider or motorglider related
fatality of the year in the US.....
Renny

-

If you include the 2 Canadians I coundt12 now.
You all seem to have missed the dead tow-pilot.

Jim

Jim,
I had not heard about the tow pilot fatality. Can you tell me where
and when this accident occurred? Sadly this year is really turning out
worse than anyone even knew....
Thanks - Renny- Hide quoted text -

- Show quoted text -


Look at the NTSB reports for 8/21

Jim

On Sep 8, 8:37*pm, Jim Britton wrote:
On Sep 8, 6:17*pm, Renny wrote:









On Sep 8, 2:33*pm, Jim Britton wrote:

On 9/8/2011 8:54 AM, Renny wrote:

On Sep 8, 7:44 am, JJ *wrote:
The NTSB just reported a Super Dimona crashed in the pattern at
Winsted, MN on 5Sept. 1 dead, 1 injured. Anybody got any more info on
this?
Does that make 8 this year?
Sad,
JJ

JJ,
Sadly, *this appears to be the 9th glider or motorglider related
fatality of the year in the US.....
Renny

-

If you include the 2 Canadians I coundt12 now.
You all seem to have missed the dead tow-pilot.

Jim

Jim,
I had not heard about the tow pilot fatality. Can you tell me where
and when this accident occurred? Sadly this year is really turning out
worse than anyone even knew....
Thanks - Renny- Hide quoted text -

- Show quoted text -

Look at the NTSB reports for 8/21

Jim

Jim,
Found it...
Thx - Renny

These calculated chances of dying in a glider accident are all over the
place, depending on who uses what data. Given the large number of glider
pilots in Germany and the meticulous way they probably keep records I
wonder what their accident rate it. Anyone seen any data on this?

in German:

http://ausbildung.bwlv.de/flusi10/un...istik_2009.pdf

and:
http://www.segelflug.ch/d/6safety/news.htm
klick on the link to an xls-File:
Statistische Erfassung seit 1997.xls


Regards
Fly safe
Marcel

Hi Gang
The NTSB preliminary report can be found he

http://www.ntsb.gov/aviationquery/br...06X63800&key=1

It sure suggests a stall and spin turning final.
Dave

On Sep 9, 1:47*pm, kd6veb wrote:
Hi Gang
* The NTSB preliminary report can be found he

http://www.ntsb.gov/aviationquery/br...06X63800&key=1

* It sure suggests a stall and spin turning final.
Dave

Description is also consistent with 360 degree turn when pilot sees he
is too high- followed shortly by going from too high to too low
and then starting to force the turn, leading to stall or stall/spin.
Alternate speculation consistent with a common "stupid pilot trick".
FWIW- not much
UH