A helicopter operator protecting Norway's vast and pristine natural environment is expanding its fleet.

Pegasus Helicopter is adding Eurocopter AS350 helicopters to its ranks at a considerable rate. The Norwegian operator welcomed its fifth, an AS350B2, at the end of April, and says three more will be on the company's books during next year.

Pegasus' work includes liming - adding calcium to soil, rivers and lakes to reverse the effects of the phosphorous contained in acid rain, other environmental work such as the aerial spraying of Norway's expansive forests, and photography missions.

It also works in the construction industry, on building projects like power lines and mobile phone antennae, transporting concrete and other heavy materials.

The company's flight operations manager, Tore Strid, says the most recent AS350 was the second to arrive at the company this year.

"For a utility aircraft for conventional charter and airborne photographic work, it's great," he says.

The B2 was purchased from France and will now be based at Pegasus Helicopters' main base, Oslo's Gardermoen Airport.

Pegasus also operates two helicopters for the Norwegian police - an EC135 and AS350B3.

It operates 12 helicopters altogether, including JetRanger and LongRanger types.

"The whole fleet is quite busy, both onshore and offshore. The [expansion in] offshore work is due to oil development and also due to the construction work in Norway, so it's been quite a good year for us so far," Strid says.