GMDSS equipment inspection frequency

GMDSS equipment inspection frequency 27.11.2019

GMDSS equipment inspection frequency

Daily, weekly and monthly GMDSS equipment tests on board

The development of GMDSS rules (Global Maritime Distress and Safety Communications System) for the shipping industry has come a long way. The GMDSS system was created with the aim of improving radiocommunication and distress procedures and ensuring maritime safety.

The greatest advantage of GMDSS equipment is that it significantly reduces the chances of ships disappearing without a trace and allows you to immediately launch search and rescue operations and direct them to a specific section of the marine disaster.

Gone are the days when ships required special radio engineers to control the radio equipment. With the implementation of the GMDSS, each deck officer with a common operator certificate (GOC) and license has the right to use the GMDSS equipment and to carry out radio communications when necessary.

In order for the GMDSS equipment to function properly and efficiently in case of emergency, it is important that seafarers understand its purpose and perform the necessary maintenance on board the vessel in order to maintain it in working condition and make the best use of the GMDSS equipment.

Daily, weekly and monthly tests of all GMDSS equipment should be carried out by each navigator responsible for it without any compromise. We must not forget that this is our only best friend in distress at sea.

Ships should be able to fulfill the nine functional requirements of the GMDSS.

  1. Ship to shore distress alert
  2. Shore to Ship Distress Warning
  3. Ship-to-ship distress alert
  4. SAR Coordination
  5. Communication on board during the incident
  6. Transmission and reception of emergency location signals
  7. Transmit and receive MSI
  8. General ship radio
  9. Communication on the bridge

This can be achieved through regular testing of GMDSS equipment.

GMDSS equipment and systems include VHF DSC / RT, MF / HF DSC / RT, INMARSAT, SART, EPIRB, NAVTEX.

GMDSS equipment daily tests

The proper functioning of digital selective calling (DSC) facilities should be checked at least once a day, without emitting signals, using equipment for internal equipment testing. A daily test checks the internal connection by transmitting the output power and display. The process may vary from equipment to equipment depending on the brand.

Daily tests should also be performed on PF / HF equipment to ensure that it will function properly in the event of a disaster.

Batteries providing a backup source of energy should also be checked daily. Mainly, ON-LOAD and OFF-LOAD battery voltages are checked by a voltmeter connected to the charger.

OFF-LOAD: if the equipment is not connected, the battery should show 24 V or a little more.

ON-LOAD: Turn off the AC power and record the battery voltage. Press PTT on the MF / HF transceiver at R / T frequency without distress and idle. The voltage will drop depending on the load. If the voltage drops by more than 10%, this indicates that the battery is weak or not fully charged. In this case, the batteries should be charged.

It is also important to ensure that all printers are operational and that there is sufficient paper.

GMDSS equipment weekly tests

It is necessary to verify the correct operation of the DSC facilities at least once a week using a test call at one of the six distress and safety frequencies when they are within the communication range of the coast station equipped with DSC equipment. You can send a test call to the coast station in the following ways:


1. Press the [DSC] key on the DSC standby screen, and then press [ENTER] to open the CALL TYPE menu.

2. Turn the [ENTER] knob to select TEST CALL, and then press the [ENTER] knob. Press the [ENTER] knob again to open the COAST ID menu.

3. Use the numeric keys to enter the identifier of the coast station (seven digits) where you want to send the call, depending on the area you are in, and then press the [ENTER] knob. The identifier of the coast station can be found in the Admiralty List of Radio Signals, Volume 1 - Marine Radio Stations.

4. Now press the [ENTER] knob to open the DSC FREQ menu. (Please note that here PRIORITY is automatically selected as SECURITY.)

5. Turn the [ENTER] knob to select the appropriate frequency, then press the [ENTER] knob.

6. Now press the [CALL] key to send a test call to the appropriate coast station. After the test call was successfully sent, a confirmation is received from the coast station. Upon receipt of confirmation, a beep will sound.

Many times, it often happens that the officer does not receive any confirmation from the coast station. In such cases, we often take for granted that the coast station does not send acknowledgment. However, in reality this may not be so.

The problem may be with our equipment. To make sure that the MF / HF equipment is in order, it is better to try to send a test call at other frequencies and to other stations. Even if then we do not receive any confirmation, a test call can be sent to the passing ship, if possible. Instead of entering the coast identifier, enter the MMSI of the ship passing by. It is better to call the ship and confirm if they received a test call. You can also ask them to send you a test call to make sure that the equipment for receiving equipment is functioning properly.

It is also recommended that testing from station to station be conducted using VHF DSC.

1. Press the call key. The message creation screen opens, where you can select the type of call. Turn the channel knob to select the TEST call.

2. Enter the station identifier, in this case the MMSI of your ship, and then press the CALL key to transmit it.

An audible and visual alarm is generated and a test call is received at another VHF station. Click Cancel to end the test call.

GMDSS equipment monthly tests


An emergency beacon or EPIRB should be checked by performing a self-test function without using a satellite system. During the self test, no alarm is transmitted.

During the self-test, the battery voltage, output power and frequency are checked. EPIRB should also be checked for physical damage. The shelf life of the battery pack and the shelf life of the hydrostat should be checked. In addition, make sure that the safety clip is correctly installed in place.

To perform EPIRB self-diagnosis:

1.EPIRB should first be removed from the bracket.

2. The spring-loaded switch at the top of the EPIRB rises to the TEST position.

A successful test will consist of a series of flashes on the LED test indicator, followed by continuous light and flash after about 15 seconds. The last green LED indicates successful testing.

3. After the test is completed successfully, the switch is released and the EPIRB is put back into the bracket.


The search and rescue transponder or SART is also equipped with a self-test mechanism to verify the operation of the beacon. SART is checked by ship's X-band radar. It is advisable that the test be conducted on the high seas to avoid interference on the radar display.

1. Remove the radar from the mounting bracket.

2. The radar test should be carried out by one person in the field of view of the radar scanner. This can be done with the wings of the bridge. Then SART should be put into TEST mode by turning it to the left to the TESTPREVUE position for a short time.

Visual lights are on and beeps are heard to indicate that the radar has fired.

3. At the same time, another person must observe the radar display for the correct picture. At least 11 concentric circles appear on the radar display if they are stored on a 12 M. scale. The distance between the two rings is approximately 0.64 m. Miles.

4. The SART should also be visually checked for any signs of physical damage. Battery life should also be noted. The safety clip must be in place.

GMDSS Portable VHF Radio

Each radio station for rescue equipment should be checked at least once a month to ensure its proper operation in the event of an emergency. It should be checked at a frequency different from channel 16 (156.8 MHz). The battery life must be checked and changed if necessary.

1. Press the power button to turn on or off.

2. To select a different channel, press the CH key and use the arrow keys to select the desired channel. The selected channel is indicated by the channel number and frequency on the screen.

3. Press PTT (Push-to-Talk) to communicate with another cordless telephone to check the transmit and receive functions. One person can stand near the VHF receiver to receive a test call from a portable radio.

The “TX” symbol is displayed when you press PTT and transmit. The TX indicator indicates that a signal is being transmitted, the antenna is transmitting.

When the radio is receiving a signal, “RX” is displayed.


Navtex is equally important GMDSS equipment and is a source of maritime safety information. It also has a test function that can test the battery, keyboard, LCD, ROM, and RAM. It is good practice to test Navtex and detect an error, if any.

1. Press the MENU / ESC key to open the main menu.

2. Now use the navigation arrows to select SERVICE, and then press ENT. The SERVICE submenu contains the TEST option. Use the down arrow key to select TEST and press the ENT key. Select YES and press the ENT key again. The TEST will begin and the results will be displayed on the screen in a few seconds.

If the test is successful, the results show OK, otherwise it shows the NG value.

It also checks the correct functioning of each key.

Test results can be printed and saved in the GMDSS journal.


INMARSAT is also equipped with a diagnostic test that checks it for proper operation. Roughly the steps for performing a diagnostic test are given below;

1. On the keyboard, press the F7 key to open the OPTIONS menu.

2. Use the down arrow to open the TEST menu, and then select DIAGNOSTIC TEST. Select YES to start testing.

Upon completion of the test, the results are displayed on the screen as shown below. The ESC key is used to return to the main menu.

A PV test or a performance test can be performed every month. This test consists of receiving a test message from the LES (Local Earth Station), transmitting the message to the LES, and a distress alert test. PV TEST can be opened from the TEST menu in the OPTIONS section, as mentioned above.

The status shows “TEST” during the test.

The status will change to IDLE after completing the PV test.

The test results can be seen in the item “PV test result” in the “TEST” menu. Test results can be printed and logged. BBER indicates the frequency of errors on the bulletin board. The passage appears without errors. “PASS” appears to satisfactorily complete the test.

GMDSS battery:

Battery and compartment connections should also be checked. The electrolyte level and specific gravity of each cell should be checked and recorded. Sulfation can reduce specific gravity, thereby reducing battery capacity. Maintenance-free batteries on board do not require such checks.

It is recommended that every month, visually check all antennas for installation reliability and visible cable damage. Antennas are located on Monkey Island. Any deposits of dirt and salt should be removed. It is also important to check the condition of the antennas and insulators using an electrician. Before doing any work on the antenna, make sure that the equipment is turned off and isolated.

GMDSS allows a ship in distress to send alerts using a variety of radio systems. Therefore, it is important that all GMDSS equipment is maintained in a ready state and in working condition. To do this, you need to conduct daily, weekly and monthly tests. Only then can we ensure the safety of the ship and its crew.


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