Fire Protection

Components of a Fire

-To have a fire, you have to have:

  • Oxygen

  • Fuel

  • Friction (Heat)

-If you remove any of these components, you can put the fire out.

Fire Classifications

  • Class A: Occurs in ordinary combustible materials, including paper and wood.

  • Class B: Occurs in petroleum products, like your hydraulic or fuel.

  • Class C: Occurs in electrical wiring/equipment.

  • Class D: Flammable material, things like magnesium, your aircraft wheels and aircraft brakes.

  • Class K: (Kitchen-type fire. We do not deal with class of fire in aviation.)

Types of Fire Extinguishers

Figure 1

  • Water and antifreeze: Class A, would not recommend being used on electrical fire due to risk of electrical shock.

  • Carbon Dioxide: Good for Class B and Class C fires. (Will cool the fire and smother the oxygen.)

  • Dry Chemical: Class B and Class C fires. (Will smother the fire but will leave residual chemicals on the aluminum and on the aircraft structure that are going to cause corrosion.)

  • Halon 1301 and Halon 1211: Class B and Class C fires.

  • Dry Powder: Typically used for metal fires. (Magnesium fires, brakes, etc. Do not put water on a magnesium fire, will cause it to explode.)

Extinguisher Inspection

-Periodic extinguisher inspection items include:

  • Proper location of the appropriate extinguisher

  • Safety seals are unbroken

  • Remove external dirt and rust

  • Gauge or indicator is in operable range

  • Proper weight

  • No nozzle obstruction

  • No obvious damage

-Look at tag of fire extinguisher to make sure it’s been inspected within the last 30 to 45 days.

Extinguisher Identification and Use

  • Extinguishers should be marked with suitability (see course eBook for details)

  • Ensure you have the correct type for the fire, then:

    1. Pull the pin to activate the agent

    2. Stand back 8 feet and aim at the base of the fire

    3. Squeeze lever and sweep side to side until extinguished

Figure 2

Fireguards

  • During technician supported ground runs, a fireguard should be used to watch for and assist in fighting engine fires during ground engine operations

  • Fireguards should be placed where they can quickly access areas of the engine that may catch fire during operations

  • Generally, the fireguard will need to direct the extinguisher at the induction system of the engine, or possibly the exhaust system

Engine Fires

  • If a fire develops during an engine start, attempt to keep cranking the engine to start.

    • If the engine starts, this will usually extinguish the fire.

  • If the engine does not start and the fire continues, terminate the start and the fireguard then extinguishes the fire.

  • Inspect the aircraft and return to service as necessary.