Sorry if I caused any upset to engineers, not intended, they are professionals also ( and I vowed I'd never fly without a F/Eng.for instance - and never did, professionally ) I just want to fly the bloody things, not fix them ! but they would be less than honest if they didn't also admit that mistakes can happen when aircraft are pulled apart and put together again, and a lot of maintenance is fixing what wasn't 'broke' in the first place, decreed by legislation based on time in service.
Sorry chaps.