User manual

Part B Section 4.1.1
4.1.1 ENGINE PERFORMANCE ICING CONDITIONS
01 GENERAL
Specific information regarding engine power settings, expected power output, performance
and fuel consumption can be found in section 5
In addition the following factors affecting engine performance should be understood.
02 CARBURETTOR ICING
Icing Conditions
Visible moisture at temperatures below freezing, either in the form of clouds or as
precipitation, forms impact ice in the air scoop and in or on the carburetor metering
elements.
High humidity with a carburetor air temperature below 30 deg C forms throttle ice on the
carburetor throttle plate at low throttle settings.
High humidity with carburetor air temperatures in the range from 0 dig to 32 degC forms
evaporation ice in the region between the carburetor and the impeller. Be alert for such
Icing, which occurs at
Relatively high temperatures in sultry weather not generally associated with ice formation.
Prolonged exposure to severe low temperature conditions, from approximately minus 5
deg C and below, can lower the fuel temperature to the point where it may cause icing in
the internal passages of the carburetor during subsequent operation in a high humidity
atmosphere. This is known as mixture control bleed icing and is usually accompanied by
severe enrichment of the mixture. It is most apt to occur if the aircraft is cold soaked for
many hours, possibly parked on the ramp. Experience indicates that it is not likely to occur
if the temperature of the fuel entering the carburetor is at or above 0 deg C.
Stichting Catalina PH-PBY Rev No: 00
18 May, 2004 Page: 1