Start hereRules checked 20 October 2026
The automatic identification system (AIS) is the ship’s electronic name badge. Every few seconds it broadcasts who she is, where she is and what she is doing, and every nearby ship, vessel traffic service and coastal authority builds its picture from those messages. If the MMSI is wrong, the GPS antenna position is entered wrongly, or the gyro input has dropped out, the ship appears to everyone else with the wrong name, in the wrong place or pointing the wrong way.
SOLAS regulation V/18.9 requires an annual test of the AIS, and the IMO circular MSC.1/Circ.1252 sets out how. In the Tokyo MOU’s 2017 PSC campaign on safety of navigation, 107 inspections in the Asia-Pacific region alone found an AIS not transmitting the correct particulars. This lesson covers the test and how to plan it.
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In this lesson
- When is the next AIS annual test due?
- In plain words
- In detail
- What the rules say
- Flag and class notes
- Key numbers
- What inspectors find
- Quiz: 6 questions
Try it
When is the next AIS annual test due?
In plain words
Once a year a qualified radio inspector, authorised by the flag or a recognized organization, comes aboard with an AIS test set. The inspector checks the installation, the ship’s fixed details (name, call sign, MMSI, IMO number, size, antenna position), the feeds of position, heading and speed from the ship’s sensors, the voyage data entry and the radio performance, and finally confirms “on the air” that a shore station or another ship can see the AIS. The result goes on a standard report, a copy of which stays on board. The dates are linked to the safety equipment survey, so the test can be a few months early or late. Between tests the officers check the AIS data themselves.
In detail
Who may test
SOLAS regulation V/18.9 requires the AIS to be tested every year “by an approved surveyor or an approved testing or servicing facility”. The circular, annex paragraph 1, says the test should be carried out by “a qualified radio inspector authorized by the administration or a recognized organization”. The HSSC Survey Guidelines, 2025 add that the survey of the AIS should always be carried out by a qualified radio surveyor who knows SOLAS, the ITU Radio Regulations and the performance standards, using suitable test equipment and following MSC.1/Circ.1252. In practice the same firm often does the GMDSS radio survey, the EPIRB annual test and the AIS test in one visit.
The six checks
MSC.1/Circ.1252, annex paragraph 2, lists what the test should include. The model test report turns them into individual lines:
| Check | Examples from the model report |
|---|---|
| .1 Installation details | Transponder type and type approval certificate; initial installation configuration report on board; antenna, AIS arrangement and block drawings; main and emergency power supply; battery capacity where an AIS runs from a battery; pilot plug near the pilot’s operating position (with a 120 V AC outlet where Panama Canal and St. Lawrence rules ask for it) |
| .2 Static information | MMSI, IMO number, call sign, name, ship type, length and beam, location of the GNSS antenna |
| .3 Dynamic information from sensors | Position with accuracy and integrity status, UTC, course and speed over ground (from GNSS), heading (from gyro), navigational status, rate of turn, heel, pitch and roll where available |
| .4 Voyage-related data | Draught, type of cargo, destination and ETA, route plan (optional), short safety-related messages |
| .5 Performance test with instruments | Frequency and transmitter output on AIS channels 1 and 2 and on DSC channel 70; polling on channel 70; reading data from and sending data to the AIS; response to “virtual vessels” |
| .6 On-air test | Reception performance, confirmation that own signal is received by another ship or VTS, polling by a VTS or shore station |
The report also asks whether electromagnetic interference from the AIS to other installations was observed. It is recorded on the model form, in English, French or Spanish or with a translation into one of them, and a copy is kept on board.
Timing: how the calculator works
The test is tied to the survey cycle, not just to a calendar year. MSC.1/Circ.1252, annex paragraph 3, allows the test:
- up to 3 months before the due date of the passenger ship renewal survey or the cargo ship safety equipment renewal survey; and
- 3 months before or after the due date of the cargo ship safety equipment periodical or annual survey.
The maximum period between tests is governed by those survey windows, unless a certificate has been extended under SOLAS I/14, in which case the Administration may grant a similar extension. IACS members interpret this to mean the test must be within the HSSC survey time window and no later than the date the survey is completed.
The calculator above gives a quick planning check. Enter the date of the last AIS test, an interval of 12 months, and an allowed extension of 3 months. It returns the nominal due date (last test plus 12 months) and the latest date (due date plus 3 months). This is a rule of thumb for a cargo ship whose last test was on the survey anniversary. The formal due date is the anniversary of the Cargo Ship Safety Equipment (or Safety) Certificate, so when the test drifted from that date, plan from the certificate anniversary instead, and for passenger ships do not use the “after” window: the test can only be up to 3 months before the due date.
Keeping the data right between tests
IMO resolution A.1106(29), the revised guidelines for the onboard operational use of AIS, gives the officers’ duties:
- AIS should always be in operation when the ship is under way or at anchor. The master may switch it off if continued operation might compromise the safety or security of the ship, record the reason in the logbook, and switch it on again as soon as the danger has passed (paragraph 22).
- The officer of the watch enters draught, hazardous cargo, destination and ETA, route plan, navigational status and safety messages at the start of the voyage and whenever they change (paragraph 23).
- Static information is checked whenever there is a reason, “as a minimum … once per voyage or once per month, whichever is shorter”, and changed only on the master’s authority (paragraph 24).
- Dynamic information, such as position, heading and speed, is checked periodically (paragraph 25).
Work it out
What the rules say
- SOLAS regulation V/18.9 requires the AIS to be tested annually by an approved surveyor or an approved testing or servicing facility, verifying static information, data exchange with sensors and radio performance by radio frequency measurement and on-air test, and requires a copy of the test report to be kept on board.1
- MSC.1/Circ.1252, annex paragraph 1, says the annual test should be carried out by “a qualified radio inspector authorized by the administration or a recognized organization”.2
- MSC.1/Circ.1252, annex paragraph 2, lists six elements: installation details, static information, dynamic information from sensors, voyage-related data, a performance test including radio frequency measurements, and an on-air test.2
- MSC.1/Circ.1252, annex paragraph 3, allows the test up to 3 months before the passenger ship or safety equipment renewal survey, or 3 months either side of the cargo ship safety equipment annual or periodical survey.2
- IACS UI SC279 interprets the timing so that the AIS test is within the HSSC survey time window and no later than completion of the survey.1
- SOLAS regulation V/19.2.4 requires AIS on ships of 300 GT and upwards on international voyages, cargo ships of 500 GT and upwards not on international voyages, and all passenger ships.3
- The HSSC Survey Guidelines, 2025, paragraph 5.12, require the survey of the AIS to be done by a qualified radio surveyor using suitable test equipment in accordance with MSC.1/Circ.1252, and paragraph (EA) 1.2.2.39 has the surveyor check that the annual test was done and the report is on board.4
- Resolution A.1106(29), paragraph 24, says the officer of the watch should check static AIS data at least once per voyage or once per month, whichever is shorter.5
Flag and class notes
- United Kingdom. MGN 465 (M+F) applies MSC.1/Circ.1252 to UK ships. It also recommends an annual “functional test” for fishing vessels over 15 m that carry Class A AIS under the EU vessel traffic monitoring directive but are outside SOLAS V/18.9, and says tests equivalent to the annual test should follow any maintenance or repair of the AIS.6
- Class approval of test firms. IACS UR Z17 applies its section on radio communication service suppliers to firms that inspect, test and maintain AIS. The firm should be familiar with the equipment, for example as a service agent of the manufacturer, have access to MSC.1/Circ.1252 and SN/Circ.227 (AIS installation guidelines), and carry equipment for testing AIS performance.7
- Flag lists. Some flags authorise radio inspectors directly; others rely on class. Ask before booking which firms your flag accepts in the port of call.4
Key numbers
| What | Value |
|---|---|
| Test interval | annual, aligned with the safety equipment survey2 |
| Window, cargo ship annual or periodical survey | 3 months either side of the due date2 |
| Window, passenger ship or renewal survey | up to 3 months before the due date2 |
| Channels checked with instruments | AIS 1, AIS 2 and DSC channel 702 |
| Static data check by the officers | at least once per voyage or once per month, whichever is shorter5 |
| Own data transmitted after switch-on | after about 2 minutes’ initialisation5 |
| Tokyo MOU 2017 campaign: AIS not transmitting correct particulars | 107 ships (1.6%)8 |
What inspectors find
- Wrong particulars. In the 2017 Tokyo MOU campaign on safety of navigation, 107 of 6,705 ships (1.6%) had an AIS not transmitting correct particulars.8
- No test report on board. The AIS test report (SOLAS V/18.9 and MSC.1/Circ.1252) is on the IMO list of documents that a port State control officer checks.9
- AIS switched off without reason. A.1106(29) expects AIS to be on whenever the ship is under way or at anchor; switching it off must be justified and logged.5
- Equipment that does not match the Record of Equipment. The surveyor checks provision and operation of the AIS and whether the annual test has been carried out.4
FAQ
Can the AIS test be done at sea?
Most of it needs test equipment connected to the AIS, and the on-air test needs a shore station or another ship in range. It is normally done in port, often together with the radio survey.
Our AIS was replaced six months after its annual test. Is the old test report still valid?
The report describes the old installation. MGN 465 recommends tests equivalent to the annual test after any maintenance or repair, and a replaced unit should at least have its installation and configuration documented. Ask the installer for a test report on the new unit and tell your flag or class.
Who may change the MMSI or ship's name in the AIS?
Under A.1106(29), static data may be changed only on the authority of the master. Some units need the installer’s password. Any change should be followed by a check that the new data are being transmitted.
Is the AIS test the same as the radio survey?
They are separate requirements. The AIS test comes from SOLAS V/18.9 and the radio survey from SOLAS Chapter I and IV, but both are normally done by a qualified radio surveyor, often in the same visit.
Quiz6 questions
Sources
- 1
SOLAS 1974, as amended, regulation V/18.9, as reproduced in IACS Unified Interpretation SC279, Annual testing of VDR, S-VDR, AIS and EPIRB (June 2016), with the interpretation on timing. https://iacs.org.uk/
- 2
IMO MSC.1/Circ.1252, Guidelines on annual testing of the automatic identification system (AIS) (22 October 2007), annex paragraphs 1 to 4 and appendix (AIS test report). https://wwwcdn.imo.org/localresources/en/OurWork/Safety/Documents/IMO%20Documents%20related%20to/MSC.1-Circ.1252.pdf
- 3
SOLAS 1974, as amended, chapter V, regulation 19, paragraph 2.4. IMO consolidated edition (sales publication). https://www.imo.org/en/About/Conventions/Pages/International-Convention-for-the-Safety-of-Life-at-Sea-(SOLAS),-1974.aspx
- 4
IMO Resolution A.1207(34), Survey Guidelines under the Harmonized System of Survey and Certification (HSSC), 2025, annex, paragraphs 5.12, (EI) 1.1.4.33.13 and (EA) 1.2.2.39. https://wwwcdn.imo.org/localresources/en/OurWork/IIIS/Documents/A%2034-Res.1207%20-%20SURVEY%20GUIDELINES%20UNDER%20THE%20HARMONIZED%20SYSTEMOF%20SURVEY%20AND%20CERTIFICATION%20(HSSC),%202025%20(Secretariat).pdf
- 5
IMO Resolution A.1106(29), Revised guidelines for the onboard operational use of shipborne automatic identification systems (AIS) (adopted 2 December 2015), annex, paragraphs 22 to 25. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/AssemblyDocuments/A.1106(29).pdf
- 6
Maritime and Coastguard Agency, MGN 465 (M+F), Navigation – Automatic Identification Systems (AIS) – Annual Testing (February 2013), paragraphs 1.1 to 1.4. https://assets.publishing.service.gov.uk/media/5a8021c840f0b62302691b4e/MGN_465.pdf
- 7
IACS Unified Requirement Z17, Procedural requirements for service suppliers, annex 1, section on firms engaged in surveys, inspections and testing of radio communication equipment (applies also to AIS) (text read: Rev.11, 2015; check the current revision). https://iacs.org.uk/
- 8
Tokyo MOU, Report of the 2017 Concentrated Inspection Campaign on Safety of Navigation, including ECDIS (November 2018), Table 1, question 7. https://www.tokyo-mou.org/wp/wp-content/uploads/CIC-Safety-of-Navigation-including-ECDIS-Report-p.pdf
- 9
IMO Resolution A.1206(34), Procedures for port State control, 2025 (adopted 3 December 2025), appendix 12, item 42. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/AssemblyDocuments/A.1206(34).pdf
Rules checked 20 October 2026. VSL Safety is not an approved training provider and doesn't issue certificates. These lessons don't replace STCW training, or the manufacturer's training and certification that service technicians need.
