What is one type of agent used in aircraft firefighting?

Foam agents are specifically designed for use in aircraft firefighting because they effectively suppress flammable liquid fires, such as those caused by aviation fuel. These agents work by forming a blanket over the burning fuel, separating it from the oxygen in the air, which is essential for combustion. This suppression not only cools the fire but also reduces the release of flammable vapors, further minimizing the risk of re-ignition.

In contrast, while water can be used in some firefighting situations, it may not be effective against flammable liquid fires, as it can spread the fuel and exacerbate the situation. Other options like sand bags and dry ice are not standard firefighting agents in an aviation context, as they do not provide the same level of effectiveness in controlling or extinguishing aircraft fires as foam agents do. Thus, foam agents are a critical tool in the arsenal of aircraft fire rescue operations.