GMDSS Radio Survey Blog
In order to ensure the operability of GMDSS radio equipment (under SOLAS-74/88, Regulations IV/15.6 and 15.7), at least two of the following methods should be used on ships navigating in sea areas A3 and A4: qualified maintenance and repair at sea; shore based maintenance; duplication of equipment.
When the vessel is operating in the sea areas A1 and A2, it is sufficient to use one of these methods, or a combination of them, by the decision of the Administration.
