During a recent annual we examined the screen in the gascolator drain located between the fuel selector valve and the boost pump. The drain was full, repeat, full of assorted fine particles of non-ferrous material.

The screen had done a good job of preventing it from getting further down stream. After cleaning, flushing and purging several times, the problem seems to have gone away. As to what caused it? My mechanic says the only way for it to have got into the system was through one of the fuel tanks. Suppliers have been known to deliver contamiated fuel! Advice: make the gascolator drain part of your routine preflight check. It is located behind an easy to remove panel on the fuselage in front of the starboard wing route. N860MK