Norway has concluded that its on-order fleet of NH Industries NH90 naval helicopters will not deliver sufficient flight hours to perform the roles originally intended for the 11t-class rotorcraft and recommends that all are converted to the anti-submarine warfare mission.

To be operated by the Royal Norwegian Air Force, 14 NH90s were selected in 2001: six to undertake frigate-based ASW operations and eight for the search and rescue and fisheries and border protection role for the coastguard.

Oslo says that to meet the requirements for both the navy and coastguard, it needs 5,400 flight hours a year from the entire fleet. But an analysis performed by the armed forces suggests that availability is only 2,100h a year.

"The analysis shows that the NH90 will not be able to meet the need for both frigate and coastguard," it says.

Instead, the report, compiled by Norway's defence research institute, recommends that all 14 helicopters – seven have been delivered so far – are dedicated to the ASW effort.

"We are now in a situation where we have to reassess how we get the most out of this investment. My recommendation is to prioritise the NH90 for frigate," says Adm Haakon Bruun-Hanssen, head of the Norwegian armed forces.

"This is because the helicopter is a weapon platform that is crucial to the frigates' ability to detect and fight submarines."

While the ASW mission cannot be performed by another platform, he notes, the coastguard's requirements could be met by civilian operators or unmanned systems.

Norway's defence ministry says it will consider the report's recommendations before making a final decision.

The analysis did not consider the acquisition of alternative helicopters, or the termination of Oslo's contract with the NHI consortium.

NHI recently delivered Norway's first NH90 in the final operating configuration standard. It will hand over four more helicopters this year, with the remainder following in 2019.