Jabiru Aircraft
Pilot Operating Handbook
Model J230-D
Revision:
6
28/2/2020
Page 23
3.2 CARBURETTOR ICING
Carburettor icing occurs when moisture in the air forms ice within the carburettor
– typically in the
venturi throat and around the throttle butterfly. The ice restricts airflow and prevents the proper
function of the carburettor.
Carburettor icing can occur in temperatures between 30°C (86°F) and -15°C (5°F). Icing
most often occurs at cruise, descent or idle power settings, in humid air (including fog, light rain or
cloud) and at ambient temperatures between 0°C (32°F) and 20°C (68°F). However, icing can
occur at other times and the pilot must be aware of the potential at all times.
Applying carburettor heat is the recommended first corrective measure to be tried in almost
any situation for the engine.
Carburettor icing symptoms include:
1.
RPM / power reducing for given throttle setting
2.
Increased throttle opening required to maintain RPM / power
3.
Rough, uneven or surging engine.
4.
Engine stoppage
If Carburettor icing is suspected:
1.
Throttle ............................................................... FULL
2.
CARB HEAT ....................................................... FULL ON
NOTE
Maintain carburettor heat in ON position for a minimum of 1 minute to allow all ice to melt.
Carburettor heat may be used at any power setting, but will result in a slight power loss. When
icing is eliminated, return CARB HEAT to OFF.
DO NOT use carburettor heat for take-offs.
Carburettor heat may be used on the ground except during take-off.
CAUTION
Do not use partial carburettor heat as this may exacerbate ice accretion.