in aircraft design there is something called the "failure mode", and every last possible thing is considered and reviewed from all possible scenarios and accident reviews. so things like wing bolts are obvious, but the door handles are also approved, and how the carpet is held down, as if it comes loose, and rumpples up under the rudder pedals, you die, and on and on and on. recently been a spate of helicopter accidents where loose objects (personal kit), have jammed controls, and the problem becomes, do you ban (shift blame) loose objects, or go all in and test and design for unjammable controlls.....which will require a slightly larger cabin with greater clearances, and controlls that are fully covered and therefor a bit heavier and harder to service.....which comes with it's own risks