Just watched an Air Crash Investigation episode in which the investigators studying the wreckage say that a certain bolt shearing off during flight caused the crash. How can they tell that the broken bolt was during flight and not because of the crash?
In: 71
If the bolt broke because of metal fatigue, it will have distinct wear marks and you can see it slowly giving way over time. This tends to be the most common cause of a metal part failing in flight. Unless the plane was hit by something especially out of the ordinary (eg: severe winds or whatever) which should have caught the eyes of the investigators early as a cause or factor in the crash.
If it happened at the time of the crash, it would show a different tear pattern as it was ripped off through raw force in the crash.
There are also other factors to consider. Once a bolt has failed, it may cause other effects on what it was holding onto. For example, if an engine bolt broke, the engine might be sagging a bit loose now, wobbling around and bending metal as it does so. That might be visible as its own damage. So combined with a bolt that was ripped off, the conclusion is the bolt came off first, then the engine start flopping around causing this other damage.
All this is generic without seeing the episode and knowing more.
Latest Answers