Very likely a combination. Nobody checked and noticed stress fatigue and NDT probably hadn’t run any scheduled tests as they cost too much.
Very likely a combination. Nobody checked and noticed stress fatigue and NDT probably hadn’t run any scheduled tests as they cost too much.
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Perhaps but fatigue is tricky and some luck is involved. By the time a fatigue crack actually shows up so that it can be found using NDT, one hopes that it will still run safely for X number of hours. However, there’s also the possibility that from the time the crack becomes evident (during operation in the sky), there many not be enough time for it to hold together before it becomes completely unraveled.
My guess is that we’re going to find that the fatigue life on this fan is much shorter than what was projected.