Radio equipment maintenance, battery care, and basic fault-finding for GMDSS installations within the restricted operator's scope
This domain tests operational maintenance within the restricted operator's scope: routine checks, battery care, and first-line fault-finding without opening sealed equipment or attempting maintainer-level repair. The exam favors safe, documented checks and fallback equipment.
Routine checks
Follow the manufacturer's schedule and the vessel's GMDSS checklist. Daily, confirm power, charger output, DSC self-test, channel 70 watch and channel 16 operation. Check the reserve source of energy and the survival-craft VHF batteries. Weekly and monthly checks may include a DSC test call to a coast station, a radio check on a working channel, and inspection of antennas and connectors. Never test the EPIRB by live transmission or the SART by activating it near a radar.
Battery care
Keep lead-acid batteries charged, ventilated and clean; check terminals and electrolyte where applicable, and record voltage and specific gravity. Do not create sparks near vented batteries. Respect the expiry dates on primary batteries in EPIRBs, SARTs and survival-craft VHF radios; replace them with the approved type. A battery that passes a voltage check may still fail under load, so follow the load-test interval in the maintenance schedule.
Fault-finding
If the VHF is dead, check the breaker or fuse, the power supply, the antenna connection and the selected channel. If it still fails, switch to the reserve VHF or survival-craft radio and report the defect. Do not open sealed DSC or EPIRB units, do not bypass fuses, and do not transmit test signals on channel 70 by voice. Record the symptom, the checks made and the equipment substituted.
Worked example
The fixed VHF display goes blank on watch. The operator checks the breaker, finds it set, measures the supply at the distribution panel and finds 12.6 V, then inspects the antenna connector and sees corrosion. The operator cleans and reseats the connector, restores normal operation, logs the fault and informs the master. If the radio had remained dead, the operator would use the reserve set and arrange shore support rather than open the transceiver.
Traps that cost marks
Do not perform a live EPIRB test or a SART activation as a routine check. Do not use channel 70 for a voice radio check. Do not replace a lithium survival-craft battery with a shop battery. Do not record a battery check without actually checking the charger and load.