Cessna SkyHawk SP 172S NAV III 2005 Pilot Operating Handbook page 160

CESSNA
MODEL 172S NAV III
SECTION 4
NORMAL PROCEDURES
COLD WEATHER OPERATIONS
(Continued)
Prior to starting on cold momings, it is advisable to tum the
propeller manually through several engine compression cycles by
hand to loosen the oil, so the engine cranks (motors) more easily
and uses less battery power. When the propeller is turned
manually, turn it in the opposite direction to normal engine rotation
for greater safety. Opposite rotation disengages the magneto
impulse couplings and prevents possible unwanted ignition.
When using an external power source, the MASTER switch ALT
and BAT sections must be in the OFF position before connecting
the external power source to the airplane receptacle. Refer to
Section 7, Ground Service Plug Receptacle, for external power
source operations.
Cold weather starting procedures are the same as the normal
starting procedures. Use caution to prevent inadvertent forward
movement of the airplane during starting when parked on snow or
ice.
NOTE
If the engine does not start during the first few
attempts, or if engine firing diminishes in strength,
the spark plugs may be frosted over. Preheat must
be used before another start is attempted.
During cold weather operations, the oil temperature indicator may
not be in the green arc prior to takeoff if outside air temperatures
are very cold. After a suitable warm up period (2 to 5 minutes at
1000 RPM), accelerate the engine several times to higher engine
RPM. If the engine accelerates smoothly and the oil pressure
remains normal and steady, the airplane is ready for takeoff.
WINTERIZATION KIT
An optional winterization kit is provided and may be utilized when
cold weather operations are conducted. Refer to WINTERIZATION
KIT in Supplements, Section 9 for installation and operational
details.
172SPHAUS-00
U.S. 4-51