How did Qantas get into a situation where 14 out of 30 Boeing 747s (of varying models and ages) all had similar defects in plumbing and the "drip shields" that protect electrical components from water?
I find it hard to believe that Qantas is the only airline with aircraft suffering from cracked drip shields. If Qantas has cracks in these shields, all airlines will: They just haven't looked yet.. or looked hard enough. Qantas was forced to look hard enough because of the incident.
The fault may very well be put down to poor design. The cracks are probably due to flexing as a result of large temperature variations. Regular inspection of this area is very difficult, because the shields are sandwiched between the cabin floor and the aircraft computers.
Perhaps Boeing need to recommend that inspection of the devices/components which led to the incident to be carried out more often and with more depth ... and engineers should be informed of the importance of the individual devices (specifically, their role in a much bigger picture).
Incidentally, this incident has already highlighted a flaw in the Boeing Maintenance Manual. It doesn't tell you which way around to mount the thermistor (heat sensor) on the plumbing for the drain masts (an integral part of the galley drain anti-icing system).
Rgds.
NSEU