Piper PA-28-236 DAKOTA, Руководство по эксплуатации для пилотов

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SECTION 3 PIPER AIRCRAFT CORPORATION
EMERGENCY PROCEDURES PA-28-236, DAKOTA
REPORT: VB-910 ISSUED: JUNE 1, 1978
3-16 REVISED: FEBRUARY 2, 1981
3.22 CARBURETOR ICING.
Under certain moist atmospheric conditions at temperatures of -5° C to
+20°C, it is possible for ice to form in the induction system, even in summer
weather. This is due to the high air velocity through the carburetor venturi
and the absorption of heat from this air by vaporization of the fuel.
To avoid this, carburetor preheat is provided to replace the heat lost
by vaporization. Carburetor heat should be full on when carburetor ice is
encountered. Adjust mixture for maximum smoothness.
3.23 ENGINE ROUGHNESS
Engine roughness is usually due to carburetor icing which is indicated
by a drop in manifold pressure, and may be accompanied by a slight loss of
airspeed or altitude. If too much ice is allowed to accumulate, restoration of
full power may not be possible; therefore, prompt action is required.
Turn carburetor heat ON (See Note). Manifold pressure will decrease
slightly and roughness will increase. Wait for a decrease in engine
roughness or an increase in manifold pressure, indicating ice removal. If no
change in approximately one minute; return the carburetor heat to OFF.
If the engine is still rough, adjust the mixture for maximum smoothness.
The engine will run rough if too rich or too lean. The electric fuel pump
should be switched to ON and the fuel selector switched to the other tank
to see if fuel contamination is the problem. Check the engine gauges
for abnormal readings. If any gauge readings are abnormal, proceed
accordingly. Move the magneto switch to L then R, then back to BOTH.
If operation is satisfactory on either magneto, proceed on that magneto at
reduced power, with mixture full RICH, to a landing at the first available
airport.