Cessna 208B - Drain Valves

CESSNA SECTION 7
MODEL
2088 (675 SHP) AIRPLANE AND SYSTEMS DESCRIPTION
FUEL SYSTEM (Continued)
DRAIN VALVES
The fuel system is equipped with drain valves to provide a means for
the examination of fuel in the system for contamination and grade.
Drain valves are located on the lower surface of each wing at the
inboard end of the fuel tank, in fuel tank external sumps on SIN
208B0001 thru 20880089 modified with SK208-52 and SIN 208B0090
and On, on the left side of the cargo pod for the reservoir tank, and on
the underside of the fuel filter. Outboard fuel tank drain valves may be
installed, and their use is recommended if the airplane is parked with
one wing low on a sloping ramp (as evidenced by the ball of the turn
and bank indicator
disolaced from center). The drain valves for the wing
tanks (and their external sumps, f instailed) are tool-operated poppa
tvoe and are flush-external mounted. The wino tank and external sump
drain valves are
const~cted so that the Phillips screwdriver on the fuel
sampler which is provided can be utilized to depress the valve and
then
twist to lock the drain valve in the open posltlon. The drain valve for the
reservoir is controlled
bv a double-button push-pull dra:n control knob.
When pulled out, fuel
ffom the reservoir drains'out the rear fuel drain
pipe located adjacent to the drain valve. The drain valve for the fuel
filter consists of a drain pipe which can be depressed upward to drain
fuel from the filter. The fuel sampler can be used in conjunction with
these drain valves for fuel sampling and purging of the fuel system. The
fuel tanks should be filled after each flight when practical to minimize
condensation.
Before each flight of the day and after each refueling, use a clear
sampler and drain fuel from the inboard fuel tank sump (and external
sump, if installed) quick-drain valves, fuel reservoir quick-drain valve,
and fuel filter quick-drain valve to determine if contaminants are
present, and that the airplane has been fueled with the proper fuel. If
the airplane is parked with one wing low on a sloping ramp, draining of
the outboard fuel tank sump quick-drain valves (if installed) is also
recommended. If contamination is detected, drain all fuel drain points
again. Take repeated samples from all fuel drain points until all
contamination has been removed. If after repeated sampling, evidence
of contamination still exists, the fuel tanks should be completely drained
and the fuel system cleaned. Do not fly the airplane with contaminated
or unapproved fuel.
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U.S. 7-79