Which extinguishing agents may be used by a fire guard near an aircraft during engine start?

• A. Water
• B. Foam
• C. Dry Powder
• D. CO2, Halon, or Dry Chemical

Answer: (D)

The situation requires an extinguishing agent that is effective on fires around an engine while minimizing risk to the aircraft and its systems during start. Water isn’t suitable here because it can spread flammable fuel, cause electrical hazards if systems are energized, and may create ice or thermal shock near hot engine components. Foam similarly is not ideal since it can contaminate surfaces, be drawn into the engine intake, and complicate the start procedure. Dry powder, though versatile, can leave abrasive residue and potentially clog small passages or damage delicate components found around the engine and start area. The best option is CO2, Halon, or Dry Chemical because these agents provide rapid fire knockdown with minimal residue and are compatible with common engine, fuel, and electrical fires encountered during engine start.