Frequency of fungus problem

[Benign]

I am considering buying an ASW-15 that is subject to the AD on fungus in the spar.  

How many ships were adversely affected by this problem?  Does anyone know the serial numbers or the cause?  Was it a load of bad balsa?

The ship I am looking at passed the lab tests and has clear plastic plates for subsequent viewing.  As I read the AD, after passing the lab tests once it is only required to do visual inspections?

In other words, what are the chances this is going to be a problem (other than in depressing resale price)?

[Jay Ky]

How many ships were adversely affected by this problem? Does anyone know the serial numbers or the cause? Was it a load of bad balsa?
Balsa was at the time of design a common material used in gliders. Unfortunately one Austrian owner thought he could store his ASW-15 outside without any protection. As a consquence water came into the wings due to rain. This water caused fungus in the spar and finaly the glider collapsed in the air. Out of this story all ASW-15 were adviced to be checked in a first step. In a 2nd step all spar were conserved with an fungicide to avoid further problems. The anual check is simply done to confirm that countermeasures are still succesful.

The ship I am looking at passed the lab tests and has clear plastic plates for subsequent viewing. As I read the AD, after passing the lab tests once it is only required to do visual inspections?
Positive lab test plus fungicide: Yes!

In other words, what are the chances this is going to be a problem (other than in depressing resale price)?
As long as you keep your ASW-15 dry you should not get any problems, nor while owning neither when selling it.

[Benign]

Thanks, Jay, that's very helpful.

[Russ]

Even, if you found a subsequent problem, It is not the end of the world.  
There is a factory procedure to replace the balsa in the spar and the birch plywood in the spar tangs.  
Your problem, then, might be to find someone who would do it.  
The best solution is to prevent fungus propagation in the first place.  As was mentioned before, make sure the glider is kept in conditions which do not subject it to excessive moisture.