Navigation Lights Failure: How to Ensure Preventive Maintenance of Marine Aids to Navigation and Their Availability Rate

The sea, a space of freedom and commerce, remains a high-risk environment for navigation.

Whether dealing with an international port, a busy estuary, or an offshore platform, the reliability of Marine Aids to Navigation (AtoN) — lighthouses, buoys, beacons, and other radio-electronic devices such as AIS — is essential to safely guide vessels. Any failure in this system can lead to serious consequences: grounding, collisions, pollution, or even loss of life.

To avoid such incidents, maritime operators must implement strict preventive maintenance — both to comply with international regulations and to optimize the operational availability of their equipment. In response to this challenge, Gisman, France’s leading provider of marine marking solutions, has developed A2NGO: a comprehensive, modular digital platform designed to support the supervision and maintenance of Marine Aids to Navigation.

A Global Regulatory Obligation

The Framework Defined by IMO and IALA

The SOLAS Convention (Chapter V) stipulates that:

“Each Government undertakes to provide such Aids to Navigation as the volume of traffic and the degree of risk may require.”

To promote uniformity, authorities are encouraged to align with the international standards and guidelines issued by the IALA (International Association of Marine Aids to Navigation and Lighthouse Authorities), which defines minimum availability thresholds based on the criticality of the equipment:

99.8% for Category 1 AtoN (high traffic density or high-risk areas),
99% for Category 2 AtoN,
97% for Category 3 AtoN.

Availability is measured as a ratio — expressed as a percentage — between the cumulative downtime (in hours) of all Marine Signal Establishments (MSEs) and the total number of hours in a reference period (one year). IALA recommends monitoring this ratio over 1,000 days, with a minimum threshold of 95%.

Non-compliance with these standards can result in serious consequences, both in terms of safety and legal liability.

National Regulations and Operator Responsibilities

In France, Marine Signal Establishments (MSEs) are managed by the Phares et Balises services. Any creation, modification, or decommissioning of an MSE requires a rigorous administrative process, including risk assessments, technical validation, and a compliant maintenance plan.

A failure to maintain equipment — when identified as a cause of an incident — may trigger the operator’s liability, whether public or private. French case law allows for a presumption of fault in the absence of maintenance or traceability records.

The Risks of Inadequate Maintenance

Neglecting or postponing the maintenance of AtoN systems means:

Jeopardizing the safety of people and assets, especially during poor weather or nighttime navigation;
Increasing the risk of port infrastructure damage;
Multiplying urgent, costly, and complex corrective interventions;
Failing regulatory compliance, with a risk of negative audits or penalties;
Damaging the reputation of the managing authority — whether it be a port, a concessionaire, or a state body.

A2NGO Supervision & Maintenance: Smart Management of AtoN

To mitigate these risks and optimize AtoN availability, Gisman has developed A2NGO, a unified digital platform designed for real-time monitoring, preventive maintenance, and performance analysis of Marine Aids to Navigation. Fully modular and interoperable, A2NGO is accessible via a secure online portal and is built around two complementary modules:

A2NGO Supervision: Real-Time Visibility

Remote management and monitoring of AtoN systems via satellite, GSM, SigFox, or AIS;
Data visualization through a clear, map-based interface;
Key features include anomaly alerts, failure alarms, and drift detection with customizable thresholds and full event logging;
Capability to extend supervision to vessel traffic control via an A2NGO AIS RELAY base station, which collects AIS messages from ships and AIS AtoN transponders within VHF range, offering a unique record-and-replay function on the market.

A2NGO Maintenance: Streamlined Planning

Custom maintenance plans configurable by IALA category and local constraints;
Automated calculation of availability rates for reporting to internal and international bodies (IALA, IMO);
Full lifecycle tracking of maintenance operations (planning, execution, reporting, archiving);
Direct integration with the Supervision module to automate diagnostics.

Tangible Benefits of A2NGO

Regulatory Compliance: automatic availability rate calculations according to IALA standards;
Cost Reduction: fewer emergency interventions and optimized maintenance scheduling;
Continuous Improvement: performance indicators, operational feedback, and streamlined audits;
Data Security: secure hosting, authenticated access, and regular backups.

Gisman: Your Trusted AtoN Partner

For over 30 years, Gisman has been supporting maritime authorities, ports, and local governments in the design, supply, and maintenance of Marine Aids to Navigation. With A2NGO, the company sets a new standard in connected, predictive, and scalable supervision, meeting the modern demands of the maritime industry.

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