A helicopter that crashed in Norway killing 13 people had to return to base twice in the days before the tragedy after a warning light was triggered.
Helicopter operator CHC confirmed that the Super Puma had to turn back to Flesland Airport in Bergen last Tuesday when the pilot spotted the indication light.
After a part was replaced a test flight the following day was also aborted and another component changed when the light reappeared.
READ MORE: Tributes to Scot killed in Norway helicopter crash
The company said the aircraft completed six commercial flights with no indications of problems on Thursday, the day before the fatal accident.
The helicopter was carrying two crew and 11 passengers from the North Sea Gullfaks B oil field, around 74 miles (120 kilometres) off the Norwegian coast when it crashed en route to Flesland.
A 41-year-old Scottish man killed in the crash has been named locally as Iain Stuart, from Laurencekirk in Aberdeenshire.
Television footage has shown what appears to be a helicopter rotor blade spiralling down minutes before the helicopter crashed.
A statement from CHC said: "It is correct that the helicopter returned to base on Tuesday 26 April.
"The pilot had a warning light and returned to Flesland according to procedure.
"At Flesland the helicopter was inspected, according to procedure, and a part was replaced.
"Wednesday, the helicopter was taken on a test flight, where the warning light reappeared, the helicopter returned to base, changed another component, the next test drive was completed without any warning light.
"Thursday, the aircraft completed six commercial flights, all without any indication of problems. None of the changed parts were physically connected to rotor or gearbox."
The statement added: "These Returns to Base (RTBs) are essential for flight safety and part of operating in a highly regulated industry. Sometimes an RTB can be for technical issues, other times it is much more mundane.
"At all times, CHC has met or exceeded the requirements of our regulatory authorities and our customers, and continues to offer a compliant service.
"Speculation about the cause of the accident is unhelpful and we must also be careful to respect the feelings of the families who perished in the tragic events of Bergen."
Mr Stuart, who worked for oilfield services company Halliburton, has been described as "always a gent" and "a top bloke" in tributes on social media.
Stephen Rennie, resident golf professional and manager at Brechin Golf Club where he was a member, told the Sunday Mail: "The whole club is shocked and saddened to hear the devastating news about Iain.
"He was a very popular member of the club and our thoughts are with his family and friends at this difficult time."
Field operators Statoil said the pilots of the helicopter - a Norwegian and an Italian - were CHC Helicopter staff.
The 10 other Norwegian passengers were employed by companies including Schlumberger, Aker Solutions, and Statoil. Their names have not yet been released.
All UK commercial passenger flights using the Airbus EC225LP - or Super Puma - model have been grounded by the Civil Aviation Authority (CAA) following the accident.
READ MORE: Tributes to Scot killed in Norway helicopter crash
More than 6,500 people have now signed an online petition calling on the CAA to permanently remove the EC225 from service.
The signatories include Audrey Wood, who lost her son Stuart when a helicopter carrying workers from a BP oil platform crashed off Peterhead in Aberdeenshire in April 2009.
A team from the UK's Air Accidents Investigation Branch (AAIB) is assisting with an investigation into the cause of the crash.
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