Back to cracks!! The fact is most, if not all, aircraft will suffer from fatigue cracks/cracking at some point or other during their life. Once discovered, the operator will inform the manufacturer/ aviation authority. The operator may well take instruction from the manufacturer, with regards to what repair to carry out or if it is considered a standard repair, the operator may follow existing guidelines on repairing the defect.
The manufacturer and the relevant aviation authority will then decide how severe the issue is and what action, if any, must be taken with regards to this defect on all the other of the type flying, both in the short/medium and long term. Some defects will require immediate attention, some won't (eg section 41 747).
So it is rather simplistic for the Aussie ALAE to call for a grounding when they neither have all the information/ the expertise (metallurgy/stress analysis/etc) or responsibility.
We all play a part in aviation and we all have to trust the other guy/girl to do their bit, in this case we have to trust the manufacturer and the aviation authorities, just as we have all done so in the past, after all, it is what they are paid to do!
