should one sump fuel-tanks before flying, if in freezing-conditions?
but this implies another question that boggles me:
Why don't aircraft have "fuel polishing" systems, to remove water from tanked fuel, especially since the cost of having a line block with ice, is so horribly high?
Cruising boats sometimes have such things, & given the peace-of-mind it'd give, why aren't these devices in play, in aviation??
( btw, it essentially is a filter & water-bypass thingy, so the water goes to the bottom of the glass bowl, & the fuel, above that, goes through the filter, if they combine them, or maybe the water-separator & the filter-unit are separate, in sequence, but both are present, before the fuel goes anywhere near the engine... )
I believe a fuel polishing system is run before firing-up an engine.
This removes all the contamination before the engine's fuel-pump even starts.
Marine Diesels, in the stuff above...
Also, this is in light of some events written about years ago...
1 was a small jet that lost power at high altitude due to slush-ice in fuel,
another was a jetliner that smashed after the same problem, ttbomk...
slush-ice in the fuel clogged something in the fuel-system, causing...
a drop in power, so therefore the crew...
increased thrust, which caused ALL the engines to clog/die, so the new recommendation was...
if in that type, at high altitude, in cold, if power reduces unexpectedly,
then reduce thrust to unclog the lines, & it should clear...
also many apparently have had problems with ice in fuel messing things up for them in piston aircraft...
also I know some are running automotive-conversions,
& if anyone ever has ethanol-blend gas in their aircraft,
& that ethanol has absorbed water, & gets cold, it can separate out,
leaving 2 distinct fluids in the tank:
ethanol-water & gasoline.
( I'm not saying running auto-fuel is legal in an aircraft,
but rather that I know human-nature. )
that link above includes some interesting stuff
also, the whole idea may be bunk,
if the amount of ice-slush in a jetliner's tanks is measured in tonnes, rather than litres,
as no catching-out device is going to handle that kind of volume.
I don't know what volume is involved.