On 30 May 2025, while connecting the gangway between Oseberg H and SOV Island Clipper, the vessel lost hydraulic pressure to the gangway (walk-to-work system). The gangway’s functions were inoperational, and the gangway was deemed unavailable for evacuation purposes.

Havtil decided to investigate the incident on 3 June.

On 28 October 2025, a similar incident occurred on Oseberg H, in which the gangway functions were inoperational, rendering the gangway unavailable for evacuation.

This incident was included in our ongoing investigation.

In both incidents, personnel on Oseberg H were evacuated by SAR helicopter to the Oseberg Field Centre.

Background

Oseberg H is located about eight kilometres west of the Oseberg Field Centre (OSF) and is remotely operated from there. Equinor is the operator. Oseberg H came on stream in 2018. SOV Island Clipper has been operating as a walk-to-work (W2W) vessel for Equinor since 2019 and is specially adapted for operations at Oseberg H. The vessel is operated and crewed by maritime personnel from Island Offshore Management. The vessel and the facility are considered a single risk unit when they are connected via the W2W system.

The gangway is the main evacuation route when personnel are present on Oseberg H.

First incident – 30 May 2025

The incident on 30 May occurred as a result of a rupture in the press coupling of one of the supply hoses, leading to loss of hydraulic pressure. The investigation points to a material defect in the coupling's press sleeve, which likely occurred during steel production. The loss of hydraulic pressure resulted in the loss of control and of emergency operation of the gangway’s functions. The gangway was moving erratically and was unavailable for evacuation purposes.

Eighteen people were evacuated by SAR helicopter to the Oseberg Field Centre.

The cone loosened from the gangway, and sparks and smoke were observed as the gangway scraped against the railings around the landing area. This led to the shutdown and depressurisation of Oseberg H. Attempts at disconnection failed because a crossmember on the underside of the gangway became caught in the railings around the landing area.

The gangway was detached from the landing area after about an hour and a half by using the pedestal’s lifting mechanism and ballasting the service operation vessel.

A failure in a single component of one of the four supply hoses in the hydraulic system resulted in the loss of gangway functions. No risk assessments have been conducted on the loss of control of the gangway when it is connected to the landing area on Oseberg H and the SOV needs to be disconnected. Consequently, it has not been determined that the railings around the landing area constituted an obstacle to disconnection.

When replacing a damaged swivel, hydraulic hoses had been temporarily installed to replace fixed pipes.

Second incident – 28 October 2025

The incident on 28 October occurred when a supply hose in the hydraulic system was ejected from its coupling, resulting in a loss of hydraulic pressure and of the gangway functions. The investigation shows that the wrong type of coupling was used. Combined with insufficient pressure during the assembly of the coupling, this caused the hose to come loose from the coupling. Attempts at emergency operation of the gangway were unsuccessful. The gangway was freed after about 13 minutes by using the pedestal’s lifting mechanism and ballasting the service operation vessel.

Three people were evacuated by SAR helicopter to the Oseberg Field Centre.

Actual and potential consequences of the incidents

The incidents caused material damage to the gangway and the landing area.

In both incidents, personnel had unrestricted access to the landing area, with no barriers in place to prevent their presence. Personnel could have been in the area, and someone could have been crossing from the gangway stairs to the bridge landing area when the incident occurred. Personal injury therefore could not be excluded, had the circumstances been only slightly different.

Direct causes

The direct causes of both incidents were ruptures in hydraulic hoses, which led to a loss of hydraulic fluid and pressure, and consequently to a loss of control of the gangway’s functions.

Underlying causes

The investigation points to the following underlying causes of the incidents:

  • Comprehensive risk assessment
  • Use of hydraulic hoses

Lessons

Learning from incidents is an important part of continuous improvement, particularly in high-risk industries such as the petroleum sector.

In this investigation, we believe that the stakeholders can learn lessons and improve their risk management practices, particularly with regard to comprehensive risk management.

To ensure comprehensive risk management when integrating a vessel, gangway and the landing area on a facility, risk assessments must take into account both technical and operational factors across the board. It is crucial to understand how the interface between the gangway, the landing area and their use can effect each other, as well as how the operational context and constraints can exacerbate risks.

The gangway’s functions are controlled hydraulically. Some parts of the hydraulic system lack redundancy. The components without redundancy are shared with the emergency control system. In the case of Oseberg H, freeing the gangway from the landing area depended on being able to lift it clear. The industry standard on which the gangway is based does not specify an interface with the landing area.

Comprehensive risk management is predicated on all parties involved – design, operation and maintenance – sharing a common understanding of their own contribution to risk and the operational consequences.

Non-conformities

The investigation identified the following regulatory breaches:

  • Inadequate risk assessment regarding the use of the gangway at Oseberg H
  • Deficient communication on Oseberg H
  • Lack of emergency response training and drills on the loss of the gangway between Oseberg H and the SOV

We also observed the following factors that we have chosen to categorise as improvement points:

  • Deficient follow-up of the gangway system

Deficient change management

What happens now?

Havtil’s investigation is now complete. We have asked Equinor to report on how the non-conformities will be addressed, and for their assessment of the improvement points observed. We have asked Island Offshore Management to provide us with their assessment of the one improvement point that pertains to them. The deadline for feedback is set at 29 May 2026.