🔍 Key Concepts

• NAVAREA warning numbering format used in the World-Wide Navigational Warning Service (WWNWS) • Difference between sequential warning number, year of issue, and any area/sub-area identifiers • How repetition of broadcasts (how many times a warning is sent) is or isn’t shown in the number

💭 Think About

• Look carefully at each part of the number 1986/87 (11). Which part most logically represents the year and which part is more likely a sequence number? • Ask yourself: in a system that issues many warnings in a year, which element would need to change most often—the first number, the second number, or the number in parentheses? • Consider whether the number in parentheses is more likely to indicate a geographical sub-region or something related to how often or where the warning is broadcast.

✅ Before You Answer

• Identify which element in 1986/87 (11) is the year of issue and which is the sequential warning number. • Decide what the number in parentheses most commonly represents in NAVAREA warnings (e.g., sub-area, topic series, or transmission-related info). • Eliminate any options that require two-year validity or meanings that would be impractical for a system that issues many warnings every year.