Specifications

8-24 Information Manual
Section 8 Cirrus Design
Handling, Servicing, Maintenance SR20
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 1887 and subsequent; 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.
March 2010