Accident analysis of diving operations related to subsea cable installation

Subsea power cables are crucial for transmitting electrical power between offshore installations, islands, and onshore infrastructure. The demand for these cables has surged with the expansion of offshore wind farms. Despite mechanisation, divers are still needed for tasks such as installation, inspection, and remedial work, facing hazards like entanglement, equipment damage, and those to the environment. Therefore, analysing accidents in diving operations during subsea cable installation is essential to develop safety measures that protect divers and ensure successful installations. This document reports an analysis of the hazards and accident events linked to diving operations during subsea cable installation. Few risk assessments of these operations have been made publicly available.
Various methods can be used to analyse diving accidents, but this document reports on the use of the Accident Anatomy (AA) method. The AA method combines fault trees and cause-consequence diagrams to map accident causes and consequences. In the AA method, evidence-based (post-accident) analysis is used jointly with predictive analysis to identify deviations from normal conditions that could lead to accidents.
To exhaust the identification of hazards, the AA method is additionally powered by an error mode classification checklist, which classifies errors that produce similar effects on a system. Analysts used this checklist to identify hazards for each basic diving operation task identified.
As a data source, 163 documents were analysed, including accident records, regulations, manuals, and scientific papers. Basic tasks associated with diving operations are identified, along with hazards for each task. Predictive analysis identifies potential events and unwanted consequences when normal conditions (specified in safety procedures and specifications) deviate. The unwanted consequences that were found include delays, technical problems, injuries, and fatalities. Ultimately, safety measures are identified for each basic task to reduce the effects of hazards.