Use Halon in a ventilated area. Your cockpit is a small confined space and will fill rapidly. Nothing really wrong with its use just open your fresh air vents.
What is Halon?
Halon (short for halogenated hydrocarbon) is a liquefied gas that is used to extinguish fire by chemically interrupting the combustion chain reaction. It is nonconducting and described as a "clean agent," as it leaves no residue after being discharged. Halon fire extinguishing agents, approved for use by the Federal Aviation Administration (FAA), include Halon 1211, Halon 1301, and a combination of the two (Halon 1211/1301). The four-digit number represents, respectively, the number of carbon, fluorine, chlorine, and bromine atoms present in one molecule. (Reference 1)
Both Halon 1211 and 1301 have Class A, B, and C ratings and have relatively low toxicity and electrical conductivity, making them the agents of choice for extinguishing the type of fires most prevalent in aircraft. Halon 1211 is a "streaming agent," and more commonly used in hand-held extinguishers because it discharges mostly as a liquid stream.
Halon 1301 is a "flooding agent," and discharges mostly as a gas, allowing it to penetrate tight spaces and behind obstacles and baffles. This property makes it ideal for use in engine nacelles and other tightly enclosed spaces commonly found in aircraft.
The Trouble with Halon
Halons have been found to be an ozone-depleting substance, harmful to the Earth's stratospheric ozone layer, and have an unacceptable "global warming potential." As of January 1, 1994, under the Clean Air Act, the United States has banned the production and import of Halons 1211 and 1301 in compliance with the Montreal Protocol On Substances That Deplete The Ozone Layer. (Reference 2)
Ozone depleting substance[edit]
The production of bromochlorodifluoromethane and similar chlorofluorocarbons has been banned in most countries since January 1, 1994 as part of the Montreal Protocol on ozone depleting substances. However, recycling of halon 1211 allows it to remain in use, although parts availability is limited to a few manufacturers and can be an issue. Halon 1211 is still widely used in the United States, despite its high cost, with the US Military being the biggest user, but Europe and Australia have banned its use for all but "critical applications" such as aviation, military, and police use.
The manufacture of UL Listed halon 1211 extinguishers was supposed to cease on October, 2009. The future listing is still in discussion. Halotron I is the replacement extinguishing agent. It takes a larger volume to get the same ratings as 1211 has.
This is a volatile extinguishing agent that should be used only with a breathing apparatus.
Abuse as an inhalant[edit]
Inhalation of bromochlorodifluoromethane and certain other fluorocarbon compounds can cause cardiac muscle sensitization to circulating epinephrine-like compounds, of which can cause an "adrenaline rush". In Australia, a Gold Coast teenager died after inhaling the contents of a yellow BCF fire extinguisher at a Southport park at about 11pm on April 7, 1994 where he and two others discharged the extinguisher, inhaling the gas. The news story also stated that six yellow BCF extinguishers were stolen from a nearby shopping centre four days earlier, which indicated it was not an isolated incident. A warning on a yellow BCF extinguisher highlighted in the news story stated that "[t]he fumes given off are liable to be dangerous, especially in a confined space."