Norwegian Air grounds Dreamliner after brake problem

I also think back, as a Brit, the problems the De Havilland Comet had due to metal fatigue. Unforeseeable because we only had turboprops to deal with up until that point and as such, speed and altitude tests did not have the benefit of computer simulations to fall back upon and that Boeing were still developing the 707 and a different design. We had massive testing tanks within hangers to allow for theoretical failures and frames were tested to destruction simulating thousands of rotations and pressure tests to simulate altitudinal variations and at temperature extremes, much of which are done on a small PC today. My point here is that the Comet evolved into a reasonable ship, learning from the earlier crashes as best we could, and it eventually was adopted and improved for service with many airlines and the RAF in varied constructs.

Airbus also have had problems with their flagship A380, despite exhaustive testing in accordance with all the regulators, it needed an inflight failure for a problem with the engine to be identified and as a result of those investigations, further problems were found within the construction of the wings. No pre certification tests could have allowed for such events but as with the DC-10, it needed an incident and time for these issues to be dealt with, in a calm manner with the ultimate purpose of providing a safe product and an enjoyable experience for those that hand over hard earned currency, and perhaps their lives, for their tickets.