Cessna 172SPHUSR05 Pilot Operating Handbook page 124

SECTION 4
NORMAL PROCEDURES
C RUISE
Normal crui s e is performed between 45% and 75% power. The
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engi n e RPM and corresponding fuel consumption for vari o us
al t i t udes can be determined by using the data in Secti o n 5.
Crui s ing shoul d be done at 75%) power as much as
practi c able until a total of 50 hours has accumulated or oil
consumption has stabi l ized. Operation at this higher power
will ensure proper seating of the ri n gs and i s appli c able to
new engines, and engines i n servi c e foll o wi n g cylinder
repl a cement or top overhaul of one or more cylinders.
The Cruise Performance charts in Secti o n 5 provi d e the pil o t wi t h
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detail e d informati o n concerning the crui s e performance of the Model
1 72S in still ai r . Power and al t i t ude, as well as winds al o ft, have a
strong influence on the time and fuel needed to complete any fl i g ht.
The Crui s e Performance Table, Fi g ure 4-3, illustrates the true
airspeed and nauti c al mil e s per gallon duri n g crui s e for vari o us
al t i t udes and percent powers, and is based on standard condi t i o ns
and zero wind. Thi s table shoul d be used as a gui d e, al o ng wi t h
the available winds al o ft informati o n, to determine the most
favorable al t i t ude and power setti n g for a gi v en tri p . The sel e cti o n
of crui s e al t i t ude on the basi s of the most favorable wind condi t i o ns
and the use of l o w power setti n gs are signi f i c ant factors that shoul d
be consi d ered on every tri p to reduce fuel consumpti o n.
In addi t i o n to power settings, proper leaning techniques al s o
contri b ute to greater range and are fi g ured into crui s e performance
tables. To achieve the recommended lean mixture fuel consumpti o n
fi g ures shown in Secti o n 5, the mixture shoul d be leaned using the
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exhaust gas temperature (EGT) i n di c ator as noted.
At lower power i t may be necessary to ri c hen the mi x ture
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slightl y to obtain smooth operation.
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NOTE
NOTE
CESSNA
MODEL 1 72S
Revi s ion 4