Tragic Double Fatality?

I don’t know if it played a role in this accident, but I do know firsthand that glue failure is a problem in Ka-7’s. When my club started to use a winch, we needed an appropriate two-seater fast, so we bought a cheap Ka-7.. We used it extensively during the 2007 season. However, at the end of the year, we decided to replace the decidedly worn fabric. As soon as we opened up the wing, biscuits began falling of the ribs. There were also other glue failures, for example at the double rib at the root of the ailerons. I wrote to Schleicher who confirmed that the glue was Kaurit, known to become brittle after a time. After consulting with a professional well versed in wooden aircraft, we considered it impossible to repair the airframe at a sensible cost and time expenditure. The glider was donated to a museum to show the internal organs. And we bought an Aerodux-glued ASK-13 to replace it....

http://imageshack.us/photo/my-images...llenoff01.jpg/

http://imageshack.us/photo/my-images...ibfailure.jpg/

On Friday, April 5, 2013 12:02:52 PM UTC-5, wrote:
I don’t know if it played a role in this accident, but I do know firsthand that glue failure is a problem in Ka-7’s. When my club started to use a winch, we needed an appropriate two-seater fast, so we bought a cheap Ka-7. We used it extensively during the 2007 season. However, at the end of the year, we decided to replace the decidedly worn fabric. As soon as we opened up the wing, biscuits began falling of the ribs. There were also other glue failures, for example at the double rib at the root of the ailerons. I wrote to Schleicher who confirmed that the glue was Kaurit, known to become brittle after a time. After consulting with a professional well versed in wooden aircraft, we considered it impossible to repair the airframe at a sensible cost and time expenditure. The glider was donated to a museum to show the internal organs. And we bought an Aerodux-glued ASK-13 to replace it....

And those with more experience with Schleicher sailplanes know that different glues were used in different places on the planes. It is doubtful that the same type of glue used to build the ribs was used to build the spars, the D-tube, or other wooden parts of the plane. Possible, but not too likely.

I, too, have seen gussets coming off of ribs on older Schleicher sailplanes.. Just like in your photos. But be careful about making the generalization that because there is an issue with the glue on the ribs that there is an issue with all the glue joints in the airplane.