What types of fire extinguishers are specified for the CRJ900?

The specified fire extinguishers for the CRJ900 are best understood in the context of safety regulations and fire prevention measures applicable to aircraft. Halon extinguishers are particularly effective for aviation use because they interrupt the chemical reaction of a fire while causing minimal damage and leaving no residue, making them suitable for use in aircraft compartments and systems.

The correct answer reflects the requirement for a combination of fire extinguishers that includes both water and Halon types, catering to different fire hazards. The one water extinguisher can be effective for general combustibles, while the three Halon extinguishers provide enhanced safety for flammable liquid fires and electrical fires, which are critical considerations on an aircraft.

In summary, this combination aligns with the safety protocols outlined for minimizing fire risks in aviation, ensuring that appropriate measures are in place to handle various types of fire emergencies effectively.