The wing root is the strongest part of any airframe. Wings falling off is way down there on the list of aviation risks, maybe next to getting struck by a meteor
Low probability or not, if an airplane can't stay in the air with one of the wings missing that definitely counts as a "single point of failure". Whether that SPOF needs to be mitigated is a tradeoff based on other constraints like the expected risk, economics, and safety regulations (and in the case of the space telescope, maximum launch mass of the rocket).
That's kind of ridiculous. A terrorist bomb in the cargo hold is a "single point of failure" that will crash the plane, as is quantum uncertainty causing one wing to break off spontaneously. This says nothing about the actual SPoF engineering requirement, which is a very real, very relevant thing.
Not as small of a risk as you’d expect (though not anything to seriously worry about). This metal fatigue grounded a large chunk of the US training fleet and similar cracks were frequently found in other Piper Arrows (including ours).
How many cycles does the airframe have to go through in order for this to become a problem? I tend to think that if the FAA gave a shit about general aviation maybe we wouldn't be flying planes from the 1960s
For airliners, the airplanes are retired after a certain number of cycles. The 757 was designed for 62,000 flying hours, if I recall correctly. It's scrap after that.
My dad's B-17 in WW2 was scrapped after 30 missions, it was considered worn out.
