The 787 is weird (and possibly unsafe) for at least two significant reasons.
Firstly, Boeing totally re-invented their approach to assembling planes. Previously they built most of the aireframe components and assembled them in their own plants. But the 787 was specced out during an ongoing Boeing/Airbus anti-trust dispute over government cross-subsidies that turned nasty (escalated to USA/EU level, mediated via the WTO, with sanctions threatened). For strategic reasons Boeing decided to outsource subassembly production to third parties and retain only overall control and final assembly (the goal was to have 51% of the work go through the EU, so that the EU would shoot themselves in the head if they applied sanctions against Boeing aircraft). (Similarly, Airbus did much the same: you can buy A320s—the 737 series' Airbus rival—built entirely in China, for example.)
Anyway, this resulted in huge cost overruns, delays as small suppliers grappled with trying to supply components of reliable quality and consistency in Boeing-scale quantities, and so on. On the other hand, it gave Boeing a shiny new 21st century supply chain which they're using on new projects, so the $30Bn wasn't entirely wasted on just one bird.
Secondly, Boeing went full-tilt for composites in place of aluminum as the main structural material.
Now, Airbus had been building composite airframes for decades at this point, but they got there incrementally, and not without fatal accidents. See for example the crash of American Airlines flight 587:
It turns out that switching to all-composites from aluminum has some serious gotchas, including entirely different wear/fatigue/delamination issues.
Boeing has done surprisingly well up to this point with the 787 (although the early Ethiopian Airlines hull loss ground-side due to a runaway battery fire should be a warning—it was a shiny new plane and the battery fire burned through the top of the hull, turning it into a $200M write-off; an aluminum bird could probably have been patched and repaired). But we have no idea whether Boeing managed to avoid baked-in long term weaknesses in the airframe, of the kind that only show up 10-30 years into an aircraft's life. Such weaknesses can show up suddenly and kill an entire type within a matter of months (see for example the fate of the Vickers Valiant, a British strategic bomber of the 1950s that succumbed to cracked wing spars and was hastily scrapped).
Anyway: this is why I'm very dubious about flying on 787s, at least for another few years. Your mileage may vary, obviously ...
The 787 is not weird. It is an evolution of practices and learning from across the industry, academia and governmental organizations (NASA, ESA, etc) that culminated in a new product. The 100% composite structure has been completely flawless for the most part, with the largest issue being how to recycle the plane when it's done. Boeing has long outsourced the production of many components of all of its planes to various vendors, the big difference with the 787 was that they did this on a global scale.
The use of LiIon batteries was a logical next step as well. Manufacturing issues in the first sets of batteries required them to re-engineer the safety system around them, and the vendors that created the batteries now have stricter standards to adhere to.
None of these issues currently compromise the safety of the airframes.
It's easy to pile-on after incidents occur, but these are machines made by people. People make mistakes all of the time. You wouldn't not use a computer because it had bugs. The likelihood of you falling out of the sky in a modern airliner is still vanishingly small and is getting smaller every day.
>The 100% composite structure has been completely flawless for the most part
Doesn't refute GP's point. All the 787s flying now are basically new planes. If they have issues that only appear after 10 years of use, they will all be "completely flawless" until they start undergoing unplanned disassembly while on the air.
Right, we don't know what the long-term usage of these composites in commercial aircraft will result in, in terms of service-life. I'm sure Boeing have their projections, and I'm sure they're optimistic. I think the larger firms will sell off their aging stock to developing nations as they approach end of life. Those nations might be inclined to extend the life of their air frames past original specifications due to economic reasons.
We know the FAA rubber-stamps whatever Boeing claims at this point, so don't expect regulators from keeping your plastic plane from disintegrating mid-flight.
The accident investigation found that the vertical stabilizer was stressed beyond its certified load limits by the pilot's rudder movements.
I can see why people were inclined to blame composites at the time of the crash. But 18 years have passed now, and there was never another incident where an A300 had a structural failure of the vertical stabilizer.
I find your first point much more relevant than your second. Boeing had been using composites extensively in military aircraft since at least their work on the B-2, and had been using composites in smaller areas from well before then. That was all was before they purchased Northrop Gumman, which brought considerably more expertise in house.
According to your "weird fatigue / sudden catastrophic failures" theory, you should be very comfortable flying on a 787 today, and become less so as the airframes age. And definitely stop flying 787s the moment one breaks up midair.
I’ve also heard that the 787 was a boondoggle.