AIS, LRIT, Anti-Dark Fleet & VDR Compliance Guide

SOLAS Regulation V/19.2.4 mandates Universal Shipborne Automatic Identification Systems (AIS) on all ships of 300 gross tonnage (GT) and upwards engaged on international voyages, cargo ships of 500 GT and upwards not engaged on international voyages, and all passenger ships irrespective of size. The primary operational objectives are ship-to-ship collision avoidance, coastal vessel traffic monitoring (VTS), and automated position tracking.

In December 2024, the IMO Maritime Safety Committee adopted Resolution MSC.570(109), establishing revised performance standards that supersede Annex 3 of Resolution MSC.74(69). Key technical requirements include:

• Broadcast Equipment Identification: AIS equipment must broadcast a unique manufacturer equipment identification number that is also physically and indelibly marked on the physical unit casing.
• Anti-Tampering & Disabling Detection: Equipment must incorporate security mechanisms that immediately detect unauthorized alteration of input data, spoofing, or system deactivation, logging an internal alert and broadcasting an integrity warning across the AIS network.
• Restricted IMO Number Modifications: Changing the vessel's IMO ship identification number within the AIS hardware or internal non-volatile memory can only be performed by an authorized manufacturer representative or recognized service agent.
• Power Supply & Rapid Startup: AIS must operate from the ship's main electrical switchboard with an automated switchover to the emergency source of electrical power, reaching fully functional tracking within 2 minutes of energization.

Under SOLAS Regulation V/19.2.4.7 and IMO Assembly Resolution A.1106(29), the default statutory rule is absolute: “AIS shall always be in operation when ships are under way or at anchor.” A ship navigating with its AIS switched off presents an acute navigational hazard and triggers immediate suspicion from coastal navies, maritime security centres, and Port State Control authorities.

• Statutory Exception Protocol: AIS may be deactivated only if the Master reasonably determines that continuous transmission directly compromises the vessel's physical safety or security (e.g. transiting known pirate ambush corridors in the Gulf of Aden, Gulf of Guinea, or active armed conflict zones).
• Official Log Book Entry: Whenever AIS is turned off, the Master must immediately record in the Official Log Book: (1) the exact reason for deactivation, (2) the geographic position and UTC timestamp, (3) the notification transmitted to the responsible coastal authority or reporting centre, and (4) the exact timestamp when AIS is re-activated once the threat has passed.
• IMO Resolution A.1192(33) Measures: Adopted at the 33rd IMO Assembly, Res. A.1192(33) targets deceptive practices employed by the “Dark Fleet” / “Shadow Fleet” to evade sanctions and export controls. Port State Control Officers (PSCOs) are instructed to inspect historical AIS/LRIT tracking logs for unexplained transmission gaps.
• MARPOL Annex I Regulation 42 Prior Notice: Any ship-to-ship (STS) transfer of petroleum cargoes in territorial waters or Exclusive Economic Zones (EEZ) must be notified to coastal authorities at least 48 hours in advance. STS operations conducted with disabled AIS or false positioning constitute grounds for immediate vessel detention, port denial, and P&I cover cancellation.

SOLAS Regulation V/19-1 mandates that all passenger ships, cargo ships of 300 GT and upwards, and mobile offshore drilling units (MODUs) automatically transmit identity, GNSS coordinates, and UTC timestamps to their Flag Administration's National Data Centre (NDC) or Recognized Cooperative Data Centre at least four times daily (every 6 hours), with capability for remote on-demand polling up to every 15 minutes.

• Conformance Test Report (CTR): Before entering service, every ship must undergo a remote satellite polling test conducted by an Authorized Testing Application Service Provider (ASP) appointed by the Flag Administration. The resulting Conformance Test Report (CTR) confirms that shipboard satellite terminals (e.g. Inmarsat-C, Mini-C, or Iridium) transmit valid LRIT data.
• No Expiry Date vs Trigger Events: Under IMO circular MSC.1/Circ.1307/Rev.1, the CTR does not expire annually. However, a new CTR is legally required whenever: (1) the ship changes Flag State, (2) the ship changes its satellite transceiver equipment or physical antenna, or (3) the recognized ASP undergoes structural decertification.
• PSC Code 30 Detention Trap: In Paris MoU, Tokyo MOU, and USCG PSC inspections, failure to produce an original Flag-authorized Conformance Test Report, or mismatch between the terminal serial number listed on the CTR and the physical unit on board, is classified as a critical safety of navigation deficiency resulting in Action Code 30 (Ship Detention) under IMO Resolution A.1206(34).

Under SOLAS Regulation V/20, all passenger ships and cargo ships of 3,000 GT and upwards constructed on or after 1 July 2002 must be fitted with a full Voyage Data Recorder (VDR). Existing cargo ships built prior to 2002 may carry a Simplified Voyage Data Recorder (S-VDR). VDR installations on or after 1 July 2014 must comply with the enhanced performance standards of Resolution MSC.333(90).

• Annual Performance Test (APT): SOLAS Regulation V/18.8 requires the VDR system to undergo an annual thorough examination by an approved manufacturer-certified testing facility. The resulting Certificate of Compliance (CoC), issued within the annual safety radio or safety equipment survey window, must be retained on the bridge.
• Emergency Backup & Casualty Preservation: In the event of a collision, grounding, engine room fire, or heavy weather damage, the Officer of the Watch (OOW) or Master must immediately depress the VDR emergency save/backup button on the remote alarm panel. Under the IMO Casualty Investigation Code (Res. MSC.255(84)), failure to preserve VDR audio and radar data following an incident is a severe statutory violation punishable by criminal sanctions in many maritime jurisdictions.

Port State Control Officers (PSCOs) inspect bridge equipment, logbooks, and electronic communication systems during every comprehensive inspection. Primary checklist items include:

• AIS Static Data Consistency: Cross-checking current voyage data (draught, hazardous cargo class, port of destination, and ETA in UTC) against the cargo manifest, passage plan, and official bridge logbook. Stale data results in Action Code 17.
• LRIT Terminal Functionality: Verifying that the LRIT power LED is illuminated, that terminal transceiver cables remain sealed without unauthorized inline switches, and that the original CTR is present in the statutory safety certificates binder.
• VDR Annual Certificate & Acoustic Beacon: Checking the expiration date of the VDR Certificate of Compliance, inspecting the battery expiration date on the underwater acoustic beacon (UAB, valid for 90 days of transmission), and testing the bridge remote maintenance display for fault indicators.
• Deficiency Action Codes: Minor clerical discrepancies in AIS voyage notes warrant Action Code 17 (rectify prior to departure); disabled AIS without logbook justification, unserviceable VDR fixed capsules, or invalid LRIT certification warrant Action Code 30 (ship detention) and mandatory Flag Administration notification.