What happened
On January 27, 2010, two Robinson R44 Astro helicopters were conducting a passenger transport mission from Melsomvik to Oslo. The lead aircraft, operated by NorCopter AS, was flying in formation with the second aircraft, LN-OCV, operated by Midtnorsk helikopterservice AS.
As the formation approached Horten, the pilots encountered a thick fog bank that obstructed their planned route. To avoid the fog, the flight speed was reduced, and the aircraft nearly came to a halt to evaluate alternative procedures. During this period of low visibility, witnesses observed the trailing helicopter, LN-OCV, undergo rapid, uncontrolled movements. The aircraft pitched downward and entered a descending right-hand spiral, eventually striking the partially frozen surface of the fjord. All four people on board were killed in the impact.
The investigation
The Norwegian Safety Investigation Authority (NSIA) examined the aircraft's configuration and the operational environment. The investigation established that the aircraft was operating under significant physical constraints. Specifically, the helicopter was overloaded, and its center of gravity was positioned too far forward, exceeding the allowable limits.
Furthermore, the investigation looked into the organizational structure of the operator. It was found that the company's operations at its Ås base were managed by a freelance pilot who also ran a separate marketing entity, HeliWing. The investigation also noted that the aircraft's carburetor heat control handle was stiff, a known issue that had not been recorded in the technical log.