Did you mean Halon?
If so Halon is probably the best extinguisher for these types of fires as Halon is an inert gas and will cause the least damage (if any at all) to a GT and the airframe.

Halon is used in computer installations because it will cause no damage to the computers if it is released.

You will also have a hard time finding a Halon extinguisher as they have been banned(?) because of their ozone layer destroying ability . There is a replacement though but I cant remember what it is called?

The next alternative would be a CO2 extinguisher, and use water if you have a grass fire.

Powder extinguishers are probably the worst next to stamping the fire out

http://www.h3r.com/halon/

Also
"halon
Organic chemical compound containing one or two carbon atoms, together with bromine and other halogens. The most commonly used are halon 1211 (bromochlorodifluoromethane) and halon 1301 (bromotrifluoromethane). The halons are gases and are widely used in fire extinguishers. As destroyers of the ozone layer, they are up to ten times more effective than chlorofluorocarbons (CFCs), to which they are chemically related.

Levels in the atmosphere are rising by about 25% each year, mainly through the testing of fire-fighting equipment. The use of halons in fire extinguishers was banned in 1994."