Fuel Contamination And Sampling - Cirrus SR22 Pilot Operating Handbook

Section 8 Cirrus Design
Handling, Servicing, Maintenance SR22

Fuel Contamination and Sampling

Typically, fuel contamination results from foreign material such as
water, dirt, rust, and fungal or bacterial growth. Additionally, chemicals
and additives that are incompatible with fuel or fuel system
components are also a source of fuel contamination. To assure that
the proper grade of fuel is used and that contamination is not present,
the fuel must be sampled prior to each flight.
Each fuel system drain must be sampled by draining a cupful of fuel
into a clear sample cup. Fuel drains are provided for the fuel
gascolator, wing tanks, and collector tank drains. The gascolator drain
exits the lower engine cowl just forward of the firewall near the airplane
centerline. Fuel tank and collector tank drains are located at the low
spot in the respective tank.
If sampling reveals contamination, the gascolator and tank drains must
be sampled again repeatedly until all contamination is removed. It is
helpful to gently rock the wings and lower the tail slightly to move
contaminates to the drain points for sampling. If after repeated
samplings (three or more), evidence of significant contamination
remains, do not fly the airplane until a mechanic is consulted, the fuel
system is drained and purged, and the source of contamination is
determined and corrected.
Airplane serials 2710 thru 3420 before SB 2X-28-08 R1; The
gascolator incorporates a filter bypass that activates a red, pop-up tab
when pressure drop across the gascolator reaches 0.8 ± 0.2 PSI. The
filter is bypassed when the pressure drop reaches 1.20 ± 0.2 PSI.
Once the pop-up tab is activated, the fuel filter element must be
replaced and the pop-up tab manually reset. Do not attempt to clean
the filter element.
If sampling reveals the airplane has been serviced with an improper
fuel grade, do not fly the airplane until the fuel system is drained and
refueled with an approved fuel grade.
To help reduce the occurrence of contaminated fuel coming from the
supplier or fixed based operator, pilots should assure that the fuel
supply has been checked for contamination and that the fuel is
properly filtered. Also, between flights, the fuel tanks should be kept as
full as operational conditions permit to reduce condensation on the
inside of fuel tanks.
8-24 P/N 13772-001
Revision A9