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Fire Extinguishers: An Overview

Prepared by AOPA's Aviation Services Department

Introduction

How many times in your life have you had to use a fire extinguisher? For most people, the answer is zero. An extremely small percentage of people can say they've had to use one on an aircraft. Fortunately, fires anywhere on board an aircraft are not very common in civil aviation. Although not a common emergency, fires on board an aircraft require immediate, decisive action on the part of the pilot. Fire extinguishers provide an easy and effective method of dealing with most fires. There are many fire extinguishers available, but few kinds provide adequate and safe use in an aircraft.

Classification of Fire Extinguishers

There are three classes of fire extinguishers, Class A, B, and C. Class A extinguishers are for ordinary combustibles like wood and paper. Class B extinguishers are for flammable liquids such as grease and gasoline. Class C extinguishers are for electrically energized fires. On board an aircraft, you want to have an extinguisher that has all three classes.

There are three types of fire extinguishers that cover all three classes; Halon, dry chemical, and CO2. Halon is by far the best choice for aircraft. Halon fire extinguishers meet the requirements of the Federal Aviation Regulation (FAR) 135.155, the Department of Transportation, the National Fire Protection Association, and are UL listed. Their small size and weight allow them to be stored easily in your aircraft. Halon is not very toxic; humans can go without any effects from Halon up to 77% concentration of total air molecules.

Dry chemical extinguishers, widely available in hardware stores, are not a wise choice for the cockpit. The smothering agent used in the bottle is very corrosive and will eat away at avionics, possibly causing thousands of dollars in unnecessary damage. In addition, the powder that is discharged will easily stick to aircraft windows, potentially blocking vision.

Carbon Dioxide (CO2) also has a number of disadvantages as compared to Halon. First, to have the same effect as a 3-pound bottle of Halon in class B and C fires, a CO2 extinguisher would have to weight 14 pounds. Also, it takes 34% concentration of CO2 to put out a fire. A 9% concentration causes a loss of consciousness after a short time if not in a ventilated cabin.

Unfortunately, Halon is not in production anymore. Due to its harmful effects on the ozone, it has been banned from production in most industrialized nations. There is a stockpile and the FAA and other organizations are looking for alternatives that don't harm the ozone. These extinguishers are still available, just at a higher price than when Halon was still being produced. Most manufacturers of fire safety products will carry Halon extinguishers. They also may be found listed in aviation product catalogs.

Placement of Fire Extinguishers

A question that pilots and owners often have is where to place a fire extinguisher on board the aircraft. Federal Aviation Regulation (FAR) Part 135.155(b) states "at least one hand fire extinguisher must be provided and conveniently located on the flight deck for use by the flight crew." The fire extinguisher should be placed in a readily available location. If possible, it should be placed where both the pilot and passengers can easily reach it. This is usually between the pilot and copilot seat in most general aviation aircraft, but another location may be best for others. Do not put it in a location where you have to squeeze through or fumble around with other items. One does not want to waste time trying to find and release the extinguisher when it comes to fire in the cockpit.

Fire extinguishers are a must in any aircraft. They may be the quickest and only way of saving you, your passengers, and your plane in case of fire. Halon extinguishers are the best choice for the cockpit at this point, but there are alternatives being developed. Prevention is the first step to fire hazard elimination, but accidents do happen. Fire extinguishers are key to helping you get out of a "hot" situation.