Its sounds obvious but contaminated fuel filters can only come from two sources:
1. The fuel being put into the aircraft tank (Fuelling/External)
2. (Internal) The aircrafts own fuel storage (tanks) and reticulation
system (fuel
lines & pumps)
1.Fuelling/External
I rarely if ever find material in my filters always visually checked at 50 hrs
and cleaned out at 100 hrs.
Ever since owning my own aircraft, I have used a filter funnel when fuelling my
aircraft, at home and on away trips. I made my own using special fuel filter
fabric & an off the shelf funnel but you can purchase a Mr Funnel to achieve the
same benefit.
I only purchase name brand fuel, from high turnover fuel stations minimal
chance
of contamination so far so good.
I use plastic 20 litre fuel containers obtained cheaply from my local hardware.
They are only used for my aircraft (ULP) so contamination can only come from
the bowser. There is nil risk of paint, rust or condensation (as long as they
are well sealed).
As I have aged, I have found it increasingly difficult to achieve a controlled
pour out of a 20 L container held at shoulder height, so have built a 12 V,
positive
displacement, vane transfer pump, using a cheap Chinese Holly copy and
fuel rated piping (almost identical to that shown by Oliver above). Very
efficient,
self-priming and with good head for high wing applications.
Fuel cap must seal against rain/dew replace O rings/seals at 5 years.
If you are putting in clean fuel, the chances of filter contamination/blockage
are reduced by almost 100%
2. Internal
Internal contamination can only come from deteriorating fuel lines, pump systems
and tank.
I always use ethanol rated, Gates Fuel Injection hose for my fuel lines and am
religiose about the 5 year replacement. New hoses must always be blown out, with
compressed air, to remove any particles/dust, insects, etc, just before fitting
never had a problem. I have almost nil experience with metal fuel lines
so wont comment.
Fuel pumps can deteriorate over time but in 12 years & 920 hrs, I havent seen
any
evidence of this happening.
Plastic fuel tanks and bladders have been known to shed particles usually when
new, anecdotally also when ethanol is present always check filters for evidence
of this starting. In my opinion, if this happens, the only safe solution is
replacement with a more durable tank.
Alloy tanks are prone to condensation I havent used a Gascolator since leaving
GA, however I do my drain checks before the first flight of the day. Even the
suspicion of water and I repeat drain, until sure none remains. Water in my
filters
& filter funnel is also something I look for - I rarely see it.
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