What happened
On the morning of August 10, 2006, an Eurocopter AS 350 B3, registration LN-ODK, was conducting a cargo sling operation in Nordland, Norway. While approaching a fuel depot at Lake Straumvatnet, the helicopter struck the water approximately 120 meters from the shore. The aircraft was carrying a loadmaster at the time. Both occupants managed to exit the helicopter before it sank to a depth of roughly 60 meters. They were subsequently rescued from the water by bystanders in a rowboat.
During the approach, the pilot encountered intense glare from the low morning sun. As the aircraft transitioned from the shadow of a nearby mountain into the sunlight, the pilot's visual references were severely compromised by the sun and the mirror-like surface of the lake. In an attempt to regain visual contact with the terrain, the pilot adjusted the flight controls, which inadvertently led to a significant loss of altitude. The crew did not realize the proximity to the water until the impact was imminent.
The investigation
The Norwegian Safety Investigation Authority (NSIA) examined the operational conditions and the organizational environment leading up to the accident. The investigation established that the pilot was operating in an unfamiliar area with only verbal directions to the landing site. Furthermore, the crew had been working under strenuous conditions; the day prior had involved a demanding schedule with maximum allowable flight and duty times, leaving the pilot with insufficient time for adequate rest and mission planning.
Findings
- The primary cause of the accident was the loss of visual references caused by sun glare and the reflective water surface.
- The pilot was under significant pressure to complete the assignment due to a lack of available experienced personnel during the holiday season.
- The mission was inadequately prepared by the operator, as the pilot lacked local knowledge and specific descriptions of the landing site.
- The pilot's workload was high, having performed extensive office duties and long flight hours in the preceding days.
- The company's risk assessment and mission planning processes were insufficient for the complexity of the task.
Safety action
The investigation resulted in several safety recommendations, including requirements for the operator to maintain updated descriptions of all fixed landing sites and to assess local hazards. Additionally, recommendations were made regarding the use of helmets and functional intercom systems for all flight personnel during inland operations, as well as a review of how on-call duties should be calculated as part of a pilot's working time.