I hope youre not saying that dirt gets sucked up when the fuel level is low like the old petrol tank myth!
Glass of parrafin, add sand
Where does the sand go?
Empty glass, add sand- where does the sand go!!
Fuel filters are inline to stop the muck getting anywhere important.
Are plane fuel tanks pressurised though?
Although, there were probably a fag butt or two left over from when the staff where topping it up...
Usually water is the primary contaminant in aviation if it ever occurs, although there is always a slim chance of rust, dirt or other assorted nasties from pipelines and fuel bowsers. If enough contaminant (obviously not water) enters the filtration system at one time it is possible to overwhelm the filter screen. The chances are infinitesimally minimal; water checks are always carried out with water detector pellets as the fuel is pumped and obviously it is filtered at every step of the journey, not just from the aircrafts internal fuel tanks to the engine. Of course in retrospect and thinking about it logically contamination is unlikely to happen at the same time as the two engines are fed from completely different tanks and crossfeed shouldnt really be used if fuel calculations are done correctly.
