Definition
A portable fire-suppression device that releases a chemical agent — typically a dry powder such as sodium bicarbonate or monoammonium phosphate, or a gaseous agent such as Halon or a Halon replacement — to extinguish a fire by smothering it, cooling it, or interrupting the chemical reaction of combustion. In aircraft, chemical extinguishers are selected for their effectiveness on electrical, fuel, and engine fires, and for being safe to discharge in confined cabin or cockpit spaces.
Plain English
A handheld bottle that sprays a chemical to put out a fire. Aircraft use them because they work on fuel and electrical fires and are safe to use inside the cockpit or cabin.
Context Anchor
Seen in aircraft emergency equipment lists, cockpit or cabin fire procedures, hangar safety equipment, and maintenance discussions about approved extinguishers.
Derivation
Chemical comes from chemistry, the study of substances and how they react. Extinguisher comes from a Latin idea meaning to put out or quench. Together, the term points to a device that puts out fire by using a substance chosen for how it acts on the fire.
Why Pilots Care
Using the correct extinguisher prevents spreading electrical or fuel fires and avoids damage that water could cause in an aircraft.
Intuition Check
Do not assume “chemical” means the extinguisher is automatically right for every fire. It means the extinguisher uses a selected substance, and that substance must be appropriate for the fire and the aircraft environment.
Example Sentence 1
During the preflight check, the pilot confirmed the chemical fire extinguisher was charged, sealed, and securely mounted within reach of the pilot's seat.
Example Sentence 2
During the walk-around, the mechanic checked that the chemical fire extinguisher was charged and within its inspection date.