FAA Aviation Mechanic General (AMG)Ground Operations and ServicingMedium
A fire breaks out in an aircraft's electrical bay due to a short circuit while the aircraft is on battery power during ground maintenance. Which type of fire extinguisher should the technician use?
- AClass D dry powder extinguisher, designed for combustible metals
- BHalon or CO2 extinguisher, rated for electrical (Class C) fires
- CWater extinguisher, because it cools the fire fastest
- DClass A extinguisher using pressurized water or foam
Show answer & explanationAnswer & explanation
Correct answer: B. Halon or CO2 extinguisher, rated for electrical (Class C) fires
Electrical fires (Class C) require a non-conductive extinguishing agent such as Halon or CO2 that will not conduct electricity back to the operator and won't damage sensitive electronics as much as water or foam. Water is conductive and dangerous on live electrical fires, and Class D powder is specifically for combustible metal fires like magnesium.
Why the other options are wrong
- A. Class D powder is for metal fires (e.g., magnesium), not electrical shorts.
- C. Water conducts electricity and poses a severe shock hazard on live circuits.
- D. Class A agents are for ordinary combustibles, not appropriate for live electrical fires.
Fire Extinguisher Classes
Fire extinguishers are matched to fire class: A (ordinary combustibles), B (flammable liquids), C (electrical), D (combustible metals).
- Class C fires require non-conductive agents like CO2 or Halon
- Water/foam extinguishers are dangerous on live electrical equipment
- Class D powder agents smother burning metals like magnesium or titanium
Memory trick: 'C' is for Circuits — keep it dry, keep it CO2.