The manufacturer gives airlines training, SOP's, manuals, etc. All the failures that occurred on previous flights were fixed according to the requirements set f

The manufacturer gives airlines training, SOP's, manuals, etc. All the failures that occurred on previous flights were fixed according to the requirements set forth by Boeing. This happens every single day on thousands of aircraft worldwide. Problems show up, the engineers fix them, and the aircraft are returned to service. I'm not sure what you're suggesting should happen... if you want Boeing to sign-off every pitot-tube cleaning or AoA sensor replacement, most planes would be grounded waiting for Boeing to show up.