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Operational procedures
If gasoline or oil encounters, for example, a hot exhaust, and if oxygen is
present, the fire can start. If you turn off the gasoline, one of the prerequisites
for the fire is removed.
If you fire the halon extinguisher, the oxygen is removed from the fire, and it
will stop.
6.6.3.1 Carburetor fire
A carburetor fire is caused by the ignition of an over primed engine. Priming can
be done either with the primer pump or with the throttle and the associated
acceleration pump.
This phenomenon is most common in the winter, when the engine can be
difficult to start.
If you pump the throttle back and forth without restraint, you create a pool of
gasoline in the intake manifold. The pool ignites when fire shoots back through
the carburetor.
It can be difficult to detect that there is a fire in the carburetor. It is impossible
to see from inside the aircraft. However, if you are aware of the risk and know
what is causing the fire, there is a chance that you can avoid damage.
Follow the manufacturer's instructions for starting the engine under different
conditions!
The general procedure for engine fires during engine start-up is:
- Engine on fire but does not run:
Continue to engage the starter, close the mixture, give full throttle to suck
the flames through the engine. After a few minutes or when the starter
will not engage anymore, take the fire extinguisher out and put out the fire
if it is still burning.
Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 585
