Cessna 152 1979, Pilot Operating Handbook

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CESSNA SECTION 3
MODEL 152 EMERGENCY PROCEDURES
1 July 1978 3- 13
6. AS ROTATION STOPS, NEUTRALIZE RUDDER, AND MAKE A SMOOTH RECOVERY
FROM THE RESULTING DIVE.
NOTE
If disorientation precludes a visual determination of the direction of
rotation, the symbolic airplane in the turn coordinator may be
referred to for this information.
For additional information on spins and spin recovery, see the discussion under SPINS in
Normal Procedures (Section 4).
ROUGH ENGINE OPERATION OR LOSS OF POWER
CARBURETOR ICING
A gradual loss of RPM and eventual engine roughness may result from the formation of
carburetor ice. To clear the ice, apply full throttle and pull the carburetor heat knob full out until
the engine runs smoothly; then remove carburetor heat and readjust the throttle. If conditions
require the continued use of carburetor heat in cruise flight, use the minimum amount of heat
necessary to prevent ice from forming and lean the mixture slightly for smoothest engine
operation.
SPARK PLUG FOULING
A slight engine roughness in flight may be caused by one or more spark plugs becoming
fouled by carbon or lead deposits. This may be verified by turning the ignition switch
momentarily from BOTH to either L or R position. An obvious power loss in single ignition
operation is evidence of spark plug or magneto trouble. Assuming that spark plugs are the
more likely cause, lean the mixture to the recommended lean setting for cruising flight. If the
problem does not clear up in several minutes, determine if a richer mixture setting will produce
smoother operation. If not, proceed to the nearest airport for repairs using the BOTH position
of the ignition switch unless extreme roughness dictates the use of a single ignition position.