GMDSS Trainer
Subelement C: Satellite Systems— Topic :

Question 26C4

Element 9 (GMDSS Maintainer)

Which of the following is the best procedure to test the Inmarsat Distress Alarm?

Explanation
Testing a distress alarm is extremely critical as it could initiate a real search and rescue operation. Therefore, any test must be performed in a way that does not generate a false alarm. **Option C is correct** because Inmarsat terminals have specific test procedures. "Service number 33" (or similar designated test service) is an internationally recognized method to contact a Land Earth Station (LES) to arrange a test transmission. This allows the terminal to confirm its functionality and connectivity with the LES without sending an actual distress alert to a Rescue Coordination Center (RCC), thus preventing false alarms. **Option A is incorrect** because lifting the cover and depressing the "DISTRESS" button is the procedure for activating a *real* distress alarm. Doing this without a genuine emergency constitutes a false alarm, which is a serious violation and could mobilize valuable rescue resources unnecessarily. **Option B is incorrect** because simply advising the US Coast Guard is insufficient for an Inmarsat system. While communication with authorities is important, the Inmarsat distress alert goes through an LES to an RCC, not directly to the Coast Guard in the same manner as a VHF DSC call. Activating the actual distress button even after notifying the Coast Guard would still trigger a false alert within the global Inmarsat system. **Option D is incorrect** because a "SAFETY" priority call is used for urgent messages concerning navigational or meteorological warnings, not for testing distress equipment. Broadcasting a SAFETY call then immediately triggering an actual distress alarm (unless it's a true emergency) would be misleading and inappropriate.