Cessna 17273274 Pilot Operating Handbook page 170

SECTION 8
HANDLING, SERVICE
& MAINTENANCE
FUEL
APPROVED FUEL GRADES (AND COLORS) --
100LL Grade Aviation Fuel (Blue).
100 (Formerly 100/ 130) Grade Aviation Fuel (Green).
Isopropyl alcohol or ethylene glycol monomethyl ether
may be added to the fuel supply in quantities not to exceed
1% or .15% by volume, respectively, of the total. Refer to
Fuel Additives in later paragraphs for additional informa­
tion.
CAPACITY EACH STANDARD TANK -- 21.5 Gallons.
CAPACITY EACH LONG RANGE TANK -- 27 Gallons.
To ensure maximum fuel capacity when refueling and
minimize cross-feeding when parked on a sloping surface,
place the fuel selector valve in either LEFT or RIGHT
position.
Service the fuel system after each flight, and keep fuel
tanks full to minimize condensation in the tanks.
FUEL ADDITIVES --
Strict adherence to recommended preflight draining instructions as
called for in Section 4 will eliminate any free water accumulations
from the tank sumps. While small amounts of water may still remain in
solution in the gasoline, it will normally be consumed and go unno­
ticed in the operation of the engine.
One exception to this can be encountered when operating under the
combined effect of: (1) use of certain fuels, with (2) high humidity
conditions on the ground (3) followed by flight at high altitude and low
temperature. Under these unusual conditions, small amounts of water
in solution can precipitate from the fuel stream and freeze in sufficient
quantites to induce partial icing of the engine fuel system.
While these conditions are quite rare and will not normally pose a
problem to owners and operators, they do exist in certain areas of the
world and consequently must be dealt with, when encountered.
8-12
NOTE
NOTE
NOTE
CESSNA
MODEL 172N
1 July 1979