Which term indicates that a procedure is mandatory in the context of SAR operations?

In the context of Search and Rescue (SAR) operations, the term that indicates a procedure is mandatory is "Shall". This term is utilized in legal and technical documents to signify obligation and enforceable requirements. When a directive states that something "shall" be done, it indicates that there is no discretion—compliance is necessary to meet safety and operational standards.

Using "must" can also indicate a requirement, but it often expresses a strong recommendation or necessity rather than the authoritative obligation implied by "shall." On the other hand, "should" suggests a recommendation or general guidance that is advisable but not strictly required. Meanwhile, "may" indicates permission or the option to follow a guideline at one's discretion, without any obligation to comply. Thus, in terms of giving clear, obligatory instructions in SAR operations, "shall" is the appropriate choice as it communicates a clear expectation without room for interpretation.