Tragic Double Fatality?

On Wednesday, April 3, 2013 12:10:07 PM UTC-5, son_of_flubber wrote:
On Wednesday, April 3, 2013 1:03:13 PM UTC-4, Liam wrote: Looks like the Ka7 might become the new Blanik. I wonder how many are still flying in the US? There are only 3 registered in the USA and none in Texas, so 2 still flying

There are 3 Schleicher K 7, 23 Schleicher Ka 7 and one Alexander Schleicher GMBH K 7.

I believe the Ka7 has a similar wing construction to the Ka2 and ASK-13; probably same wood and glue used in Ka6, Ka10, ASK14, and ASK18. There is some debate about what glue was used where in which gliders. It seems the factory was not consistent.

Of course this isn't necessarily a glue failure accident either. Time will tell.

Originally Posted by Tony[_5_]

On Wednesday, April 3, 2013 12:10:07 PM UTC-5, son_of_flubber wrote:
On Wednesday, April 3, 2013 1:03:13 PM UTC-4, Liam wrote: Looks like the Ka7 might become the new Blanik. I wonder how many are still flying in the US? There are only 3 registered in the USA and none in Texas, so 2 still flying

There are 3 Schleicher K 7, 23 Schleicher Ka 7 and one Alexander Schleicher GMBH K 7.

I believe the Ka7 has a similar wing construction to the Ka2 and ASK-13; probably same wood and glue used in Ka6, Ka10, ASK14, and ASK18. There is some debate about what glue was used where in which gliders. It seems the factory was not consistent.

Of course this isn't necessarily a glue failure accident either. Time will tell.

FYI

Details of BGA inspections on K7 and others

http://www.gliding.co.uk/bgainfo/tec...04-issue-3.pdf

Argh!!! Another fatality which may have been avoided if we had better accident information sharing globally!

Ramy

I guess its too early to know what happened. But as a comment, I did
personally witness an inflight structural failure in a wooden glider back
in the
UK. It turned out to be caused by an effect called a 'compression shake'
which is when a compression overload leaves the wood with a fine defect
that
is very weak in tension, so it can fail in tension at a later time, maybe
years
later. These shakes can apparently be detected by a careful visual
examination, by someone who knows what to look for, eg after an unusually
heavy landing or shock. Also there is a BGA note about glue joint
inspections
in gliders like K7s. I don't know if the FAA pass these on to US owners.

http://www.gliding.co.uk/bgainfo/tec...07-2004-issue-
3.pdf

On Thursday, April 4, 2013 12:23:23 AM UTC-4, Ramy wrote:
Argh!!! Another fatality which may have been avoided if we had better accident information sharing globally! Ramy

The accident that triggered the UK action was no secret and the findings were made available, even if not widely published on RAS.
No new findings resulted. It did trigger the requirement for more rigorous inspection.
One sad reality is that the few people who really know how to inspect and maintain old wood structure gliders are fading away. The new A&P's and IA's are very well versed in documentation, but not so well trained in some of these less used skills.
Sadly
UH

On Wednesday, April 3, 2013 11:23:23 PM UTC-5, Ramy wrote:
Argh!!! Another fatality which may have been avoided if we had better accident information sharing globally! Ramy

Maybe and maybe not, Ramy. If you have not yet, I would encourage you to go read the report on the one in the UK. The wing failed about one meter outboard of the fuselage. Roughly where the drag spar attaches to the main spar. On this recent accident in Texas, the eyewitnesses say the wing failed at roughly half span.

It could well be that it was the same basic cause (compression fracture in the lower cap that reduced its tension load carrying capability), but as Hank noted, there are fewer and fewer good "wood people" out there. However, I know we have a couple of them assisting the NTSB with information, and how to access proper information for this investigation.

Steve