For all the best pilots in the world out there, who want some information from a 'simple' engineer, here's something that would hopefully clear up all the misinformation (or disinformation) out there.
No ribs on the A380 ever cracked. Its the RIB FEET (or attachment brackets) that fix the ribs to the wing lower skin that are cracking.
As of now, the four metallic ribs that Airbus claims to be primary structure in the wing don't have any cracks on their feet.
The rest (26, I think) of the CFRP ribs have feet that are cracked. Airbus claims (tongue-in-cheek) that these are secondary structure and give the wing its profile.
Now, to the cracks:
The original type 1 cracks, as they call them, originate from the fastner holes in the horizontal web of the rib feet. i.e. the rib feet are L-shaped in cross section, and the horizontal portion is bolted to the wing lower skin, while the vertical portion of the foot is bolted to the rib. The fastners that join the skin to the feet are an interference fit; so it seems that as the fastners are driven into the holes in the feet, the feet crack. The cracks radiate outwards from the holes. Some cracks have been severe enough to propagate to the edge of the material.
Interestingly, brand new wings (pre-assembly) received in Toulouse from the UK have been found to have multiple cracks. This is "GOOD" news, because it means the cracks are a production issue, and not fatigue related. One proposal from Airbus is to make these holes a clearance fit, as a quick fix. Material expansitivity, flex, etc. will all need to be re-assessed in the long run.
What is worrying are the type 2 cracks, which seem to be fatigue related, but are, thankfully, quite rare as of now. These originate from the edge of the feet, at the corner of the "L" and propogate inwards. Since a lot more research needs to be done to fix this, the quick fix is to replace the cracked feet with new (but still unmodified) ones. A mod program will be out as soon as Airbus figures out what is going on.
Down time for one airplane is around 3-5 days for inspection, and another 10-15 days for repairs (currently done by Airbus personnel).
Those are the facts, as I know them. No airline/manufacturer bashing.
