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2015/11 eng

Report on incident approx. 120 NM southwest of Sola, Norway 4 October 2013, with Sikorsky S-92A, LN-ONW, operated by Bristow Norway AS

En route from Valhall to Sola several cautions regarding the main gear box oil system gave cause for concern. The crew considered that it was too risky to continue toward land, and chose to make an emergency landing at the decommissioned oil rig Yme. The possibility that there could be a critical failure in the main gear box, also made the crew consider a possible emergency landing at sea before the helicopter reached Yme.

There was no damages during the emergency landing. The crew and passengers were later picked up by a rescue helicopter and flown ashore. The investigation has shown that a minor technical error had triggered a number of misleading cautions. The current emergency checklist was incomplete and did not provide adequate support for decision making.

After the incident, the manufacturer revised the emergency checklist. The AIBN is however of the opinion that further improvements is needed, and has issued a safety recommendation in this regard.

Safety recommendation

Safety recommendation SL No. 2015/11T

On 4 October 2013, LN-ONW made an emergency landing on the evacuated Yme oil rig. A minor technical fault in the main gearbox resulted in indications which the crew perceived to be serious.The Accident Investigation Board is of the opinion that the emergency checklist for the main gearbox on the S-92A was complicated and difficult to understand, particularly in a stressful emergency situation. This view is supported by the operating company Bristow Norway AS. After this incident, Sikorsky has revised the relevant parts of the emergency checklist, and started a redesign process to improve the warning/caution system on the main gearbox. The Accident Investigation Board Norway is however of the opinion that further improvements is needed, and therefore recommends that Sikorsky revise the emergency checklist with the aim of further simplification and increased user-friendliness.


Location 120 NM southwest of Sola, Norway
Occurrence date 04.10.2013
Aircraft Sikorsky øvrige
Operator Bristow Norway AS
Registration LN-ONW
Meteorological conditions VMC
County Rogaland
Type of occurrence Incident
Type of operation Offshore
Category of operation Heavy, helicopter (> 2 250kg)
Aircraft category Helicopter, Multi-engine, Turboprop/turboshaft

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