AVIATION authorities in Norway have extended their ban on the use of Airbus H225 Super Puma helicopters to include search and rescue missions as investigations continue into the cause of a fatal crash which killed 13 people in April, including a Scottish offshore worker.

The helicopters, a staple for the offshore industry, were grounded from commercial traffic in Norway and Britain following the crash on April 29, but search and rescue operations were previously exempt.

The total ban by Norway's Civil Aviation Authority come after investigators ruled out human error and blamed a technical fault for the accident, with a preliminary report pointing to metal fatigue in parts of the main gearbox.

Everyone on board died when the offshore helicopter came down near the small island of Turoey while en route to Bergen. Iain Stuart, 41, from Aberdeenshire was among those killed in the crash.

The Norwegian report urged officials to take immediate action to ensure Super Puma H225 helicopters are safe.

The Norwegian Air Accident Board warned that current fault detection measures may be inadequate.

A spokesman for the UK's Civil Aviation Authority (CAA) said it would mirror the advice of the Norwegian authorities, but added that "less than a handful" of UK search and rescue helicopters - believed to be around three of four - were the Airbus H225 model.

Most are either Sikorsky or AgustaWestland

The Airbus H225 Super Puma, previously known as a Eurocopter EC225, has been involved in a string of previous non-fatal crashes.

In 2009, an EC225 Super Puma with 18 on board missed an oil platform and crashed in the North Sea after the crew became disorientated during the night landing.

In May 2012, 14 people had to be rescued from the North Sea when the pilot of another EC225 Super Puma carried out a controlled ditching after experiencing problems with the main gearbox lubrication system. Investigators later discovered a 360-degree circumferential crack in the bevel gear vertical shaft in the main gearbox.

Five months later, in October 2012, 19 people were rescued when a third EC225 ditched off Shetland. The model was temporarily grounded worldwide after investigators found another 360-degree crack in the same piece of equipment, which was interfering with the function of the aircraft's oil pumps.

A spokesman for Airbus Helicopters said they were "reviewing" the latest report from Norway.

He added: "In light of this important new finding, we continue to fully support ?AIBN, EASA, our customers and the ongoing investigation by providing information in full transparency.

"Safety of the passengers travelling in our helicopters remains our chief priority. We do not wish to comment further as the investigation continues."

An online petition calling for all Super Puma 225s to be "permanently removed from service" has attracted nearly 30,000 signatures.