What does AAR-47 indicate as a hazard?

The AAR-47 is a system used primarily for detecting and identifying various types of incoming threats to an aircraft, particularly in terms of missile threats. It utilizes multiple sensors to assess potential risks from heat and infrared sources in the environment. Among the options provided, the identification of a hazard by the AAR-47 would typically be related to missile threats rather than the specific items listed in the answers.

"Double Nickel Salt" refers to a type of sodium-based compound and is not directly related to aviation hazards or the function of the AAR-47. Therefore, the focus would typically be on understanding that the AAR-47 relates to identifying threats such as hostile fire or incoming missiles rather than any of the environmental hazards indicated in the other choices.

Understanding the AAR-47's purpose helps clarify why it would not indicate lead poisoning, fire hazards, or chemical spill risks, as these issues are outside the operational parameters of this detection system. It focuses specifically on identifying threats to the aircraft rather than environmental or health concerns.