What defines GMDSS Sea Coverage Area A4?

• A. Beyond Areas A1, A2, and A3; Generally defined as the regions north of 70N and south of 70S.
• B. Within Areas A1, A2, and A3.
• C. Global coverage including all oceans.
• D. Between Areas A3 and A4 only.

Answer: (A)

Polar regions beyond 70 degrees latitude define this sea coverage area. These zones sit outside the regular patterns used closer to shore and in the main global coverage areas, because radio propagation and satellite coverage behave differently near the poles. As a result, the GMDSS designates these extreme latitudes as a separate area to reflect the limited or different service reach there, guiding how distress and safety communications are handled for ships operating in Arctic and Antarctic waters. The other descriptions don’t fit: being inside the closer zones isn’t correct, global coverage isn’t accurate for these polar caps, and there isn’t just a belt between the main areas—A4 is specifically the polar regions beyond 70° latitude.