Safety recommendation SL no. 2019/01T

On 21 June 2018 OH-HNX, a helicopter from Heliwest hit a crossing power line and cut all three conductors. The risk of collision with crossing lines is very real in connection with helicopter work at low altitude along power lines. This is e.g. illustrated by the fact that, over a six-month period, Agder Energi Nett had three incidents in connection with work along the company's power distribution network. Sweden and Finland have introduced requirements for physical marking of power lines before they are crossed by overhead cables. The AIBN believes such marking could, to a substantial degree, prevent the risk of collision.

The Accident Investigations Board Norway recommends that the Civil Aviation Authority introduce requirements for physical marking of crossing lines in Norway.

Safety recommendation SL nr. 2013/02T

A large number of OCAS installations are currently out of service.

The Norwegian Accident Investigation Board therefore recommends that the Norwegian Civil Aviation Authority immediately find compensatory measures to ensure that obstacles to aircraft in flight equipped with OCAS installations get a satisfactory warning system.

Safety recommendation SL nr. 2013/03T

The Norwegian Accident Investigation Board is of the opinion that difficult and partly misleading information about OCAS installations degrades the warning system efficiency.

The Norwegian Accident Investigation Board recommends that information about the system's functionality, active frequencies and individual installation locations must be substantially improved in order to reach important user groups.

Safety recommendation SL no. 2013/04T

The Norwegian Accident Investigation Board is of the opinion that future systems for obstacle warning to aircraft in flight should be based on readily available equipment/methods such as the use of GPS and electronic maps. A database of obstacles already exists at NRL.

The Norwegian Accident Investigation Board therefore recommends that the Norwegian Civil Aviation Authority in collaboration with a map provider find a solution so that this information can be made conveniently available to actual user groups.