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Gliding risk....



 
 
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  #1  
Old December 6th 19, 11:05 AM posted to rec.aviation.soaring
Terry Slater[_2_]
external usenet poster
 
Posts: 2
Default Gliding risk....

At 22:33 05 December 2019, 2G wrote:
On Thursday, December 5, 2019 at 11:15:08 AM UTC-8, Dave Walsh wrote:
At 16:14 05 December 2019, 2KA wrote:
Yeah, the entire fleet was inspected and repaired as required=20

(years ago),
and SH paid for the whole thing. Gliders built at the factory=20

in Germany
were found to be affected, as well as those built at=20

contractors.

Lynn Alley
"2KA"

=20
You were lucky! I was in a UK owned DuoDiscus based at=20
Sisteron, France, a few years ago. Wing spar de-bonding was=20
discovered at an annual inspection even though the glider had,=20
in theory, been inspected previously, looking for this specific=20
manufacturing fault. SH DECLINED TO PAY FOR THIS REPAIR;=20
if I recall correctly each of us in the 8 man syndicate had to=20
cough up about =C2=A3700.......
Dave Walsh


This is particularly disturbing, raising the question of the

effectiveness
=
of the original inspection method(s). Do the logbook(s) detail how and
when=
this inspection was done? How did the current annual discover the
de-bondi=
ng?

Tom

The inspections were performed with an endoscope, and the full length of
the spar bonding was inspected visually. SH issued a very comprehensive
guide to the process.

Terry

  #2  
Old December 6th 19, 09:53 PM posted to rec.aviation.soaring
2G
external usenet poster
 
Posts: 1,439
Default Gliding risk....

On Friday, December 6, 2019 at 3:15:05 AM UTC-8, Terry Slater wrote:
At 22:33 05 December 2019, 2G wrote:
On Thursday, December 5, 2019 at 11:15:08 AM UTC-8, Dave Walsh wrote:
At 16:14 05 December 2019, 2KA wrote:
Yeah, the entire fleet was inspected and repaired as required=20
(years ago),
and SH paid for the whole thing. Gliders built at the factory=20
in Germany
were found to be affected, as well as those built at=20
contractors.

Lynn Alley
"2KA"
=20
You were lucky! I was in a UK owned DuoDiscus based at=20
Sisteron, France, a few years ago. Wing spar de-bonding was=20
discovered at an annual inspection even though the glider had,=20
in theory, been inspected previously, looking for this specific=20
manufacturing fault. SH DECLINED TO PAY FOR THIS REPAIR;=20
if I recall correctly each of us in the 8 man syndicate had to=20
cough up about =C2=A3700.......
Dave Walsh


This is particularly disturbing, raising the question of the

effectiveness
=
of the original inspection method(s). Do the logbook(s) detail how and
when=
this inspection was done? How did the current annual discover the
de-bondi=
ng?

Tom

The inspections were performed with an endoscope, and the full length of
the spar bonding was inspected visually. SH issued a very comprehensive
guide to the process.

Terry


Yeah, I read their TN 396-08 that covered the process. This required cutting several holes in each wing for access by the endoscope. Of course, these holes had to be repaired and refinished. It would have been so much easier and cheaper to have done this inspection by ultrasonic NDT.

Tom
  #3  
Old December 6th 19, 10:13 PM posted to rec.aviation.soaring
Eric Greenwell[_4_]
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Posts: 1,939
Default Gliding risk....

2G wrote on 12/6/2019 1:53 PM:
On Friday, December 6, 2019 at 3:15:05 AM UTC-8, Terry Slater wrote:

Tom

The inspections were performed with an endoscope, and the full length of
the spar bonding was inspected visually. SH issued a very comprehensive
guide to the process.

Terry


Yeah, I read their TN 396-08 that covered the process. This required cutting several holes in each wing for access by the endoscope. Of course, these holes had to be repaired and refinished. It would have been so much easier and cheaper to have done this inspection by ultrasonic NDT.


If the SH wing is constructed like the ASH26E wing, there is a layer of foam
between the outer skin and inner skin that is glued (hopefully) to spar. I suspect
ultrasound would not be effective, so what would kind of NDT would be used?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
  #4  
Old December 7th 19, 10:09 AM posted to rec.aviation.soaring
krasw
external usenet poster
 
Posts: 668
Default Gliding risk....

Reading this forum, sounds like biggest safety risks in gliding a

- Any glider or radio that has had an AD in it's history
- Rogue thermals
- Mysterious medical symptoms that occur only when flying

Other that that, we are pretty safe.
  #5  
Old December 9th 19, 06:30 AM posted to rec.aviation.soaring
2G
external usenet poster
 
Posts: 1,439
Default Gliding risk....

On Saturday, December 7, 2019 at 2:09:19 AM UTC-8, krasw wrote:
Reading this forum, sounds like biggest safety risks in gliding a

- Any glider or radio that has had an AD in it's history
- Rogue thermals
- Mysterious medical symptoms that occur only when flying

Other that that, we are pretty safe.


The biggest safety risks have been, and continue to be, pilot error.

Tom
  #6  
Old December 10th 19, 12:10 AM posted to rec.aviation.soaring
Bob T
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Posts: 38
Default Gliding risk....

On Saturday, December 7, 2019 at 3:09:19 AM UTC-7, krasw wrote:
Reading this forum, sounds like biggest safety risks in gliding a

- Any glider or radio that has had an AD in it's history
- Rogue thermals
- Mysterious medical symptoms that occur only when flying

Other that that, we are pretty safe.


Regarding the rogue thermal comment... they can occur. I came VERY close to becoming a statistic a few years ago while thermalling about 1500 ft. agl and wrote a feature article for SOARING MAGAZINE dealing with it. Rather than stalling an inside wing in a thermal turn (as one would expect if you happened to fly too slowly), while thermalling at about 10-15 kts above stall speed my INSIDE (lower) wing suddenly was pushed up and over, resulting in a steep dive / spiral. Subsequent research showed that some thermals can have strong down cores inside of overall lift, and if a glider happened to hit the sheer boundary, with suddenly one wing in the up air and the other in the down air, your day could quickly end.

See https://www.danlj.org/~danlj/Soaring...b_Thompson.pdf

and Dr. Dan Johnson had a good one, too https://www.danlj.org/~danlj/Soaring...Jan-p12-15.pdf

There are 2 books I referred to in my classes that have some pretty good info, too, although they are mostly intended for business folks:
1. Will Your Next Mistake Be Fatal? by Robert E. Mittelstaedt, Jr. for example - on page 160 - Insight #29 - Culture is powerful - what creates success may kill you. Think about this one seriously, for a long time! What you, or others, have gotten away with for a number of times can lead to complacency... and you becoming a statistic... that you couldn't tell anyone about ... from the grave. I recently attended a "celebration of life" for a friend that I suspect may have either lost his life due to his prior successes or rogue air.
2.Why We Make Mistakes by Joseph T. Hallinan



  #7  
Old December 10th 19, 06:31 AM posted to rec.aviation.soaring
2G
external usenet poster
 
Posts: 1,439
Default Gliding risk....

On Monday, December 9, 2019 at 4:10:16 PM UTC-8, Bob T wrote:
On Saturday, December 7, 2019 at 3:09:19 AM UTC-7, krasw wrote:
Reading this forum, sounds like biggest safety risks in gliding a

- Any glider or radio that has had an AD in it's history
- Rogue thermals
- Mysterious medical symptoms that occur only when flying

Other that that, we are pretty safe.


Regarding the rogue thermal comment... they can occur. I came VERY close to becoming a statistic a few years ago while thermalling about 1500 ft. agl and wrote a feature article for SOARING MAGAZINE dealing with it. Rather than stalling an inside wing in a thermal turn (as one would expect if you happened to fly too slowly), while thermalling at about 10-15 kts above stall speed my INSIDE (lower) wing suddenly was pushed up and over, resulting in a steep dive / spiral. Subsequent research showed that some thermals can have strong down cores inside of overall lift, and if a glider happened to hit the sheer boundary, with suddenly one wing in the up air and the other in the down air, your day could quickly end.

See https://www.danlj.org/~danlj/Soaring...b_Thompson.pdf

and Dr. Dan Johnson had a good one, too https://www.danlj.org/~danlj/Soaring...Jan-p12-15.pdf

There are 2 books I referred to in my classes that have some pretty good info, too, although they are mostly intended for business folks:
1. Will Your Next Mistake Be Fatal? by Robert E. Mittelstaedt, Jr. for example - on page 160 - Insight #29 - Culture is powerful - what creates success may kill you. Think about this one seriously, for a long time! What you, or others, have gotten away with for a number of times can lead to complacency... and you becoming a statistic... that you couldn't tell anyone about ... from the grave. I recently attended a "celebration of life" for a friend that I suspect may have either lost his life due to his prior successes or rogue air.
2.Why We Make Mistakes by Joseph T. Hallinan


A thermal may not be your standard British thermal, but a confluence of several, competing mini-thermals. I have seen up to six, or more, dust devils converging to make a single thermal. However, in 40 years of flying, much in the very dynamic high western desert, I have never been upset in the manner you describe. This is not to say it can't happen, but I think the typical glider accident is much more mundane and the direct result of poor airmanship.

Tom
  #8  
Old December 10th 19, 02:03 PM posted to rec.aviation.soaring
Tango Whisky
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Posts: 402
Default Gliding risk....

Le mardi 10 décembre 2019 07:31:14 UTC+1, 2G a écritÂ*:
On Monday, December 9, 2019 at 4:10:16 PM UTC-8, Bob T wrote:
On Saturday, December 7, 2019 at 3:09:19 AM UTC-7, krasw wrote:
Reading this forum, sounds like biggest safety risks in gliding a

- Any glider or radio that has had an AD in it's history
- Rogue thermals
- Mysterious medical symptoms that occur only when flying

Other that that, we are pretty safe.


Regarding the rogue thermal comment... they can occur. I came VERY close to becoming a statistic a few years ago while thermalling about 1500 ft. agl and wrote a feature article for SOARING MAGAZINE dealing with it. Rather than stalling an inside wing in a thermal turn (as one would expect if you happened to fly too slowly), while thermalling at about 10-15 kts above stall speed my INSIDE (lower) wing suddenly was pushed up and over, resulting in a steep dive / spiral. Subsequent research showed that some thermals can have strong down cores inside of overall lift, and if a glider happened to hit the sheer boundary, with suddenly one wing in the up air and the other in the down air, your day could quickly end.

See https://www.danlj.org/~danlj/Soaring...b_Thompson.pdf

and Dr. Dan Johnson had a good one, too https://www.danlj.org/~danlj/Soaring...Jan-p12-15.pdf

There are 2 books I referred to in my classes that have some pretty good info, too, although they are mostly intended for business folks:
1. Will Your Next Mistake Be Fatal? by Robert E. Mittelstaedt, Jr. for example - on page 160 - Insight #29 - Culture is powerful - what creates success may kill you. Think about this one seriously, for a long time! What you, or others, have gotten away with for a number of times can lead to complacency... and you becoming a statistic... that you couldn't tell anyone about ... from the grave. I recently attended a "celebration of life" for a friend that I suspect may have either lost his life due to his prior successes or rogue air.
2.Why We Make Mistakes by Joseph T. Hallinan


A thermal may not be your standard British thermal, but a confluence of several, competing mini-thermals. I have seen up to six, or more, dust devils converging to make a single thermal. However, in 40 years of flying, much in the very dynamic high western desert, I have never been upset in the manner you describe. This is not to say it can't happen, but I think the typical glider accident is much more mundane and the direct result of poor airmanship.

Tom


In 39 years of flying, I have once been upset by a thermal (entering at a speed of 130 kph, 300 m over the rocks in the central Alps, 4 m/s climb after recovery).
A second time such an upset was caused by a rotor (vertical speeds varying between -12 m/s and +12 m/s, trying to work it at 150 kph), but it didn't really come as a surprise.
  #9  
Old December 10th 19, 05:00 PM posted to rec.aviation.soaring
Dan Marotta
external usenet poster
 
Posts: 4,601
Default Gliding risk....

I've been upset as described, but it was rotor, not a thermal.

There's no substitute for training...

On 12/9/2019 11:31 PM, 2G wrote:
On Monday, December 9, 2019 at 4:10:16 PM UTC-8, Bob T wrote:
On Saturday, December 7, 2019 at 3:09:19 AM UTC-7, krasw wrote:
Reading this forum, sounds like biggest safety risks in gliding a

- Any glider or radio that has had an AD in it's history
- Rogue thermals
- Mysterious medical symptoms that occur only when flying

Other that that, we are pretty safe.

Regarding the rogue thermal comment... they can occur. I came VERY close to becoming a statistic a few years ago while thermalling about 1500 ft. agl and wrote a feature article for SOARING MAGAZINE dealing with it. Rather than stalling an inside wing in a thermal turn (as one would expect if you happened to fly too slowly), while thermalling at about 10-15 kts above stall speed my INSIDE (lower) wing suddenly was pushed up and over, resulting in a steep dive / spiral. Subsequent research showed that some thermals can have strong down cores inside of overall lift, and if a glider happened to hit the sheer boundary, with suddenly one wing in the up air and the other in the down air, your day could quickly end.

See https://www.danlj.org/~danlj/Soaring...b_Thompson.pdf

and Dr. Dan Johnson had a good one, too https://www.danlj.org/~danlj/Soaring...Jan-p12-15.pdf

There are 2 books I referred to in my classes that have some pretty good info, too, although they are mostly intended for business folks:
1. Will Your Next Mistake Be Fatal? by Robert E. Mittelstaedt, Jr. for example - on page 160 - Insight #29 - Culture is powerful - what creates success may kill you. Think about this one seriously, for a long time! What you, or others, have gotten away with for a number of times can lead to complacency... and you becoming a statistic... that you couldn't tell anyone about ... from the grave. I recently attended a "celebration of life" for a friend that I suspect may have either lost his life due to his prior successes or rogue air.
2.Why We Make Mistakes by Joseph T. Hallinan

A thermal may not be your standard British thermal, but a confluence of several, competing mini-thermals. I have seen up to six, or more, dust devils converging to make a single thermal. However, in 40 years of flying, much in the very dynamic high western desert, I have never been upset in the manner you describe. This is not to say it can't happen, but I think the typical glider accident is much more mundane and the direct result of poor airmanship.

Tom


--
Dan, 5J
  #10  
Old December 10th 19, 05:15 PM posted to rec.aviation.soaring
Jonathan St. Cloud
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Posts: 1,463
Default Gliding risk....

On Monday, December 9, 2019 at 10:31:14 PM UTC-8, 2G wrote:

A thermal may not be your standard British thermal, but a confluence of several, competing mini-thermals. I have seen up to six, or more, dust devils converging to make a single thermal. However, in 40 years of flying, much in the very dynamic high western desert, I have never been upset in the manner you describe. This is not to say it can't happen, but I think the typical glider accident is much more mundane and the direct result of poor airmanship.

Tom


We'll make sure that gets printed on your tombstone. Back when I was a young pilot and working toward my multi-engine instrument I read a story in NTSD briefs or reports or one of the bi-weekly pamphlets publications I was reading about fly/IFR, regarding a 7,000 hour ATP that stalled a Beech Baron on short final. I thought how could you be so dumb. That evening I was doing a night instrument training flight in a rent-a-wreck piper Semihole. This particular evening the buzzing in the headsets had been louder than normal. This was my first night flight after the airport installed a displaced threshold. While on long final, I thought I heard tower clear an aircraft to taxi onto the active runway and hold. I was gentling pulling myself up, by the yoke, to look over the cowling. The stall horn went off and to me it was lost in the background buzzzing noise in the electrical system. The instructor put his palm on the yoke and pushed it forward enough for the horn to stop. I was still concentrated on looking over cowling pull myself up by the yoke, the horn went off for a second time and the instructor said" I got it. " It was not until then I understood what I had been doing and what I had been ignoring. I never again thought I was beyond making a mistake! I try to stay very alert, I keep learning and I keep flying. Could I make an airmanship mistake, you bet I could. Because I know I can screw up, I keep up with training, flying, Condor, reading about flying, and staying fit to fly. When The above don't come together I am fast to ground myself. I think only a foolish pilot would think they can't make a mistake.

Stay safe out there,
Jon
 




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