Crab, as usual you are absoluty correct. You got in first re your last mail however will still give my input in the hope it will add something useful. I think I may have attended a similar series of lectures on composite structures, construction, stress paths and conditions leading to the degrading of structural integrity. One issue was the detection of de-lamination and the integrity of the bonding agent. As you say put simply metal structures tend to relieve stress loads by flexing, composite remain ridged, hence absorb these loads within the structure. The issue re continuing structural strength with no obvious signs of de-bonding of the skins as in this case it seems, is tricky to detect. Tapping the skins with a coin just doesn’t do the job. I do understand that ultra sound systems can give a better indication of the condition of the honeycomb central core and its bonding to outer skins.
In short, without visible external indications it’s almost impossible to gauge internal structural integrity.
Repair of this type of structure is another matter and extremely complex and generally outside the capacity of the operator. I would be very surprised if the repair indicated in this thread was concerned with the structure, rather more lightly to have been non- structural parts, and with the guidance and approval off A.
That all being said lessons need to be learnt and I am sure they will be.
I remember the discussions on this type of construction years ago when they first arrived and the reluctance of us non believers to believe that they could replace the metal structure