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Investigation of helicopter incidents on Ringhorne

With the assistance of the Civil Aviation Authority (CAA), the Petroleum Safety Authority Norway (PSA) has prepared a report in connection with the investigation of helicopter incidents involving an incorrect landing on 6 November 2003 and a near incorrect landing on Ringhorne on 19 January 2004.


Basically, the incidents are the result of incorrect identification of the destination (the facility).

RinghorneBoth incidents are associated with helicopter flights on the route from Flesland - Grane, with Norsk Hydro (Hydro) as the oil company/petroleum operator and CHC Helikopter Service (CHC HS) as helicopter company/transportation contractor.

The incident on 6 November 2003 entailed an actual incorrect landing on Ringhorne (photo), while the incident on 19 January 2004 can be described as a near incorrect landing on the same installation.

The latter incident is described in detail in the report. ExxonMobil is the operator on Ringhorne.

The investigation has been carried out in a comprehensive context, and therefore deals with aspects that fall under the formal authority of both the PSA and the CAA.

Description of the course ov events

Incorrect landing on Ringhorne, 6 November 2003

The helicopter flight on 6 November 2003 was a high-profile trip in connection with the formal opening of the Grane platform. A Sikorsky S-61N is used for the flight, and takes off as planned. The helicopter arrives at Grane after 1 hour and 20 minutes.

The helicopter has to refuel, and takes off after 30 minutes to refuel on Heimdal. On the flight to Heimdal, they pass 2 nautical miles east of Ringhorne without noticing this.

The helicopter refuels and takes off again to fly back to Grane. The pilot discovers a facility and reverts to visual flight, without checking the radar for actual position.

The pilots perform the normal preparations for landing, and also receive clearance to land from Grane (although no one on Grane has seen any helicopter).

The helicopter lands on Ringhorne and the pilots discover that they are on the wrong facility when they see the name on the helicopter deck and the GPS instrument shows that they are 5.1 nautical miles from Grane. They then take off for Grane and land there after about two minutes.

Near incorrect landing on 19 January 2004

The helicopter flight on 19 January 2004 with departure at 1545 hours was one of the normal flights to Grane and, based on the weather report (TAF), the trip was planned without refueling (no alternative landing site needed).

After departure from Flesland to Grane, the weather report was updated and the helicopter had to plan for an alternative landing site, and thus needed more fuel.

The helicopter could not refuel on Heimdal, which is the closest Hydro facility to Grane, and instead had to fly to Oseberg A to fill extra fuel.

On this particular day, the wind conditions on Oseberg A led to restrictions in landing weight, and they cannot receive the helicopter from Grane unless passengers are taken off. Therefore, the passengers disembark on Brage, the helicopter flies empty to Oseberg A and refuels. It then flies to Brage again and picks up the passengers before setting course for Grane.

It is starting to get dark when the helicopter approaches the Grane area (a few minutes before 1800 hours), but the pilots are still flying on visual. The pilots prepare to land on the basis of the visual information and the radar information they have on the area.

The pilots are not aware that the information on the radar indicates an incorrect position for Grane (although they are aware that the information may be unstable).

The helicopter comes all the way in to the helicopter deck (a distance of about 40 m) before the pilots discover that they are on Ringhorne instead of Grane, and break off the approach. The radar screen is updated and they fly south and land on Grane. The distance between Ringhorne and Grane is 5.1 nautical miles.

None of the incidents entailed injury to personnel or damage of material assets, however, both had a potential for substantial safety consequences as the helicopter decks were not cleared for landing.

During the investigation, the PSA has also considered other helicopter incidents in order to identify, if possible, issues that may be of a more general nature for helicopter transport on the Shelf.

The report identifies examples showing that the use of risk analyses can be used in a more comprehensive and systematic approach to reinforce the basis for making decisions.

The investigation showed that underlying causes linked to human, technical and organizational factors were not sufficiently illuminated in the internal company investigations associated with the incidents.

It also emerges from the report that both helicopter companies and operators should strengthen focus on near-misses where failure of barriers is a predominant cause. It may be just as important to investigate these types of incidents as incidents with actual consequences.

Observations show that neither the helicopter company nor the operator appear to have gone far enough back in the chain of events in their own investigations. Weaknesses have also been noted as regards analytical depth/thoroughness.

The report emphasizes that the significance of the helicopter contract as an administrative barrier to achieve improvement of safety, human, organizational and technical aspects should be considered.

It has also been revealed that the system for transfer of experience and information between the involved companies can be improved in order to strengthen expertise levels and improve safety.

It emerges from the report that marking of facilities and communication and navigation equipment can be improved. Similarly, registration and measurement of weather data of significance for the helicopter traffic on the Shelf can be improved.

It is recommended that the factors identified in the report that relate to the authorities be addressed in a cooperation between the involved authorities.

Link: Report after investigation of two helicopter incidents (pdf, Norwegian only)

Contact in the Petroleum Safety Authority Norway:
Inger Anda
Press spokesperson
E-mail:
inger.anda@ptil.no
Telephone: +47 970 54 064