FOD/Loose articles
This is not a new problem unique to Boeing. I remember a story (possibly in Air Clues) from many years ago, about a Beverley which suffered from a loud thumping noise from under the freight deck floor whenever there was turbulence. The cause could not be ascertained during its service life. When the aircraft was scrapped a 6 foot (10 foot?) length of steel scaffolding pole was discovered, which had been there since manufacture.
At about the same time another aircraft type had problems with clogged fuel filters. Eventually traced to a blanket left in a fuel tank during manufacture. But probably the prize goes to the dining room chair left in a large fuel tank (Sunderland?).
