Gliding risk....

Clemens, can you analyze vs "under the influence of competition" factor?

can you analyze vs "under the influence of competition" factor?

Brett - I wanted to do that as well. Unfortunately, it's not enough to know how many accidents occur in competition. To understand if competition flying is more dangerous than regular flying (and by how much), I would need to know what percentage of flights occur in competition vs. pleasure flights vs. training flights. Unfortunately, I don't think this information exists and I think a guess would be too inaccurate. If you have a good source, please let me know. Clemens

On Wednesday, October 30, 2019 at 8:49:22 PM UTC-4, wrote:
For those who haven’t seen it....

https://chessintheair.com/the-risk-o...-what-we-love/

Great piece of work which I shall read again in March!

A few comments;

"if you dread the thought of a field landing....."
then you should set up a simulation on your own field and practice till
you are confident.

No pilot should EVER be criticised for deciding on a field landing; I suppose this must happen; very immature behavior.

Duo Discus in flight wing failure.
The German report ( thanks Google) says that there was an unbonded section
on the spar some 20cm long. Surely an ultrasound scan of the spar line
would reveal this. I have no experience/ expertise in this regard.

John Firth

On Friday, November 22, 2019 at 11:49:15 AM UTC-8, john firth wrote:
On Wednesday, October 30, 2019 at 8:49:22 PM UTC-4, wrote:
For those who haven’t seen it....

https://chessintheair.com/the-risk-o...-what-we-love/

Great piece of work which I shall read again in March!

A few comments;

"if you dread the thought of a field landing....."
then you should set up a simulation on your own field and practice till
you are confident.

No pilot should EVER be criticised for deciding on a field landing; I suppose this must happen; very immature behavior.

Duo Discus in flight wing failure.
The German report ( thanks Google) says that there was an unbonded section
on the spar some 20cm long. Surely an ultrasound scan of the spar line
would reveal this. I have no experience/ expertise in this regard.

John Firth

Thanks for pointing the Duo Discus manufacturing problem. Here is a link to the BFU report:
https://www.bfu-web.de/EN/Publicatio...ublicationFile

A couple of disturbing findings in this report:

"Manufacture of the wings was based on the knowledge of Schempp-Hirth at Kircheim which was not available as written instructions. This was true for the processes during manufacture, the specification of materical (e.g. adhesives) and the criteria for quality assurance (tolerances)."

Instead, employees from the subcontractors spent time at Kircheim to learn all of this. This system would utterly fail any quality control evaluation (e.g. CE), and is disturbing to me as a potential customer. Furthermore, this was the SECOND wing failure of an S-H product in the same year:

"The accident to the Discus CS in France revealed an even more extensive bonding defect on the wing spar."

This Discus had been in service for some time prior to the failure (900 hrs and 900 launches), so time in service is no security blanket. All Discus gliders were grounded in France after this accident:

https://groups.google.com/forum/#!to...ng/MTRTAwPn7qA

Yes, ultrasonic nondestructive testing can reveal such defects, but I don't know of any glider repair facilities that use them. I have designed such products in the past and have connections with a local NDT company. I will reach out to them to see how feasible such testing is. In the mean time, you can do a crude kind of NDT test by tapping on the surface above the bond with a metal object like a coin and listen to the sound produced. A defective bond will sound different than a good bond (less sharp and duller):

https://www.aviationpros.com/home/ar...aft-composites

Before I purchased any glider manufactured by either of these subcontractors I would insist on a full-blown ultrasonic NDT test.

Tom

On Wednesday, December 4, 2019 at 4:54:08 PM UTC-5, 2G wrote:

Before I purchased any glider manufactured by either of these subcontractors I would insist on a full-blown ultrasonic NDT test.

This relevant accident happened in 2003.

Before I get my nickers in a twist, I'd like to know whether the manufacturing deficiencies have been addressed in the intervening 16 years.

On Wednesday, December 4, 2019 at 7:53:57 PM UTC-8, son_of_flubber wrote:
On Wednesday, December 4, 2019 at 4:54:08 PM UTC-5, 2G wrote:

Before I purchased any glider manufactured by either of these subcontractors I would insist on a full-blown ultrasonic NDT test.

This relevant accident happened in 2003.

Before I get my nickers in a twist, I'd like to know whether the manufacturing deficiencies have been addressed in the intervening 16 years.

Well, my nickers ARE in a twist: I need to learn more to get them untwisted. This kind of slip-shod manufacturing puts a cloud over the whole industry.

On Wednesday, December 4, 2019 at 7:53:57 PM UTC-8, son_of_flubber wrote:
On Wednesday, December 4, 2019 at 4:54:08 PM UTC-5, 2G wrote:

Before I purchased any glider manufactured by either of these subcontractors I would insist on a full-blown ultrasonic NDT test.

This relevant accident happened in 2003.

Before I get my nickers in a twist, I'd like to know whether the manufacturing deficiencies have been addressed in the intervening 16 years.

Sounds like a recent story about Boeing...
https://boingboing.net/2019/12/02/ra...-shavings.html

"...Barnett says the 787 facility was run by a new leadership team that had been transferred in from St Louis, MO, with a background in overseeing military contracts, and that they prioritized production speed over airworthiness and safety.

He says that the culture of poor safety began in 2011 or 2012, with top management ordering employees not to document defects, but that this graduated to "ignoring safety issues and the defective parts." Barnett pursued this internally, exhausting every internal process and facing workplace retaliation before going to federal regulators like the FAA and OSHA, which resulted in even more retaliation, and, eventually, blackballing across the aviation industry."

On Wednesday, December 4, 2019 at 8:43:39 PM UTC-8, 5Z wrote:
On Wednesday, December 4, 2019 at 7:53:57 PM UTC-8, son_of_flubber wrote:
On Wednesday, December 4, 2019 at 4:54:08 PM UTC-5, 2G wrote:

Before I purchased any glider manufactured by either of these subcontractors I would insist on a full-blown ultrasonic NDT test.

This relevant accident happened in 2003.

Before I get my nickers in a twist, I'd like to know whether the manufacturing deficiencies have been addressed in the intervening 16 years.

Sounds like a recent story about Boeing...
https://boingboing.net/2019/12/02/ra...-shavings.html

"...Barnett says the 787 facility was run by a new leadership team that had been transferred in from St Louis, MO, with a background in overseeing military contracts, and that they prioritized production speed over airworthiness and safety.

He says that the culture of poor safety began in 2011 or 2012, with top management ordering employees not to document defects, but that this graduated to "ignoring safety issues and the defective parts." Barnett pursued this internally, exhausting every internal process and facing workplace retaliation before going to federal regulators like the FAA and OSHA, which resulted in even more retaliation, and, eventually, blackballing across the aviation industry."

Yeah, Boeing used to be run be engineers in Seattle. That changed when they moved their headquarters to Chicago in 2001. Now, engineers became a necessary nuisance and profit became king. When they tried to farm out most subsections of the 787, with only final assembly being done in Seattle, they ran into major problems: the subs really didn't know how to make aircraft. These are the kind of blunders bean-counters make, with no sense of what made the company great. The 737 Max is just the latest, if not the worst, blunder. They didn't even designate the MCAS as flight critical, so it didn't get the attention it deserved. And then they charged extra for it to operate off of both AOA sensors that were on the plane anyhow - a colossal bean-counter screw-up: charge extra for basic safety! Heads need to roll in top management, although they will wait until after the current crisis is over.

On Wednesday, December 4, 2019 at 10:53:57 PM UTC-5, son_of_flubber wrote:
On Wednesday, December 4, 2019 at 4:54:08 PM UTC-5, 2G wrote:

Before I purchased any glider manufactured by either of these subcontractors I would insist on a full-blown ultrasonic NDT test.

This relevant accident happened in 2003.

Before I get my nickers in a twist, I'd like to know whether the manufacturing deficiencies have been addressed in the intervening 16 years.

SH issued an AD on affected ships. Presumably all were inspected and repaired as needed a long time ago.
I recall that SH did take action to document the process areas that had been done only by hands on training. I don't have written info on this.
SH stepped up on this and did what I consider a good job when the issue was identified. I had an affected glider at the time and the inspection was prompt, thorough, and cost free.
UH

Yeah, the entire fleet was inspected and repaired as required (years ago), and SH paid for the whole thing. Gliders built at the factory in Germany were found to be affected, as well as those built at contractors.

Lynn Alley
"2KA"