Fatal Super Puma helicopter crash 'not caused by technical fault' The Super Puma helicopter crash that killed four oil workers last Friday was not caused by an airworthiness or technical problem, the Civil Aviation Authority (CAA) believes. The decision to return the Super Puma fleet to service after a temporary suspension on flights is "appropriate," the regulator also said. The CAA said it would not have allowed the helicopters to return to the skies unless it was satisfied that it was safe to do so. A spokesman said: "As the UK's aviation safety regulator, protecting the public is our fundamental purpose. It was right that Super Puma operations were suspended in the immediate aftermath of the accident on August 23 until further information was available. Since the accident, our experts have been in close touch with the Air Accident Investigation Branch, the helicopter operators, the European Aviation Safety Agency, the Norwegian regulator and others. We have reviewed and assessed the evidence available, including the information already published by the Air Accident Investigation Branch and detailed information provided to us by the operators. Our team of specialists includes pilots who are experienced in flying the Super Puma AS332 L2 in the North Sea environment. Based on all the information currently available, we do not believe that the accident was caused by an airworthiness or technical problem, and consider that the decision by the operators to resume Super Puma flights is appropriate. The regulator said it would review its position if any new evidence came to light. Flights were suspended after the AS332 L2 Super Puma crashed as it approached Sumburgh airport on the southern tip of Shetland, killing three men and one woman. Step Change In Safety's helicopter safety steering group (HSSG) recommended yesterday that the Super Puma fleet should return to service as there was "no evidence" to continue the suspension. The L2 type involved in the crash will initially be re-introduced for non-passenger operations such as training flights. Operators, trade unions and regulators are to engage with the offshore workforce to "rebuild trust and confidence" and a "sympathetic" approach would be taken to any worker who feels unable to fly, the HSSG said. The Super Puma is said to make up about half of the UK offshore industry's 75-strong helicopter fleet and the freeze caused disruption to the movement of workers on and offshore. Les Linklater, Step Change In Safety's team leader, said there were almost 16,000 people offshore, with more than 12,000 in the areas most affected by the suspension - the central and northern North Sea. He said: "There are over 250 people who have spent more than 21 days offshore. This is increasing daily and they and their families are wondering when they are going to get home. Industry has a duty of care to all offshore workers both in terms of their safety and their well-being; we must consider the cumulative risk of the 'time out'. We must avoid a further tragedy through the introduction of human factor-based risk such as fatigue, stress and other well-being concerns that increase the likelihood of a high consequence-low frequency event. By taking the time out for safety over the weekend, we have had the opportunity to review key elements of our fleet and better understand the positions of the authorities that determine the airworthiness and operational compliance and safety of our helicopter fleet. Helicopter operators were satisfied there is no inherent mechanical problem with any of the Super Puma models, the HSSG said. The European Aviation Safety Agency and Civil Aviation Authority had taken no action in relation to the Super Puma models, which "positively affirms that there are no safety reasons that support a suspension of flying," the group said. The pilots' union Balpa gave its full support to the fleet and the helicopters had continued to fly in other parts of the world, it added. Unite Scottish secretary Pat Rafferty said: "The continued grounding of the L2 fleet -- the same type involved in last Friday's crash resulting in four fatalities and also in the April 2009 crash with 16 fatalities -- is the bare minimum that the industry can do until the recovered black box's data fully establishes why this tragedy occurred. The decision of the Helicopter Safety Steering Group (HSSG) to return the Super Puma L type, L1 type and the EC225 type, as per its original service plan, to UK offshore operations should be approached with caution and sensitivity. Confidence has been shattered and the industry needs to provide substantive evidence - not opinion - to its workers, demonstrating the airworthiness of the helicopters that are now returning to operations. At the same time, Unite is demanding guarantees from employers that workers who feel unable to fly will not be subject to pressure or the threat of dismissal. The industry cannot merely expect the workforce to simply get their boots on and get back to work. Bob Crow, general secretary of the RMT transport union, said he backed the decision to return the Super Pumas to service, in light of the evidence currently available. Mr Crow told BBC Radio Scotland's Good Morning Scotland programme: "We agree with the decision, we've been party to this decision. We've looked at all the evidence. You've got to weigh up, at the end of the day, the pressures on individuals who are stranded on rigs and want to get back, or who've been away from work for two to three weeks. Also, at the end of the day, we've got to look at the evidence that was put in front of us and (on) the evidence at this moment in time there's no reason why the crash was mechanical. Air accident investigators are to examine the Super Puma's black box voice and flight data recorder which was recovered on Thursday. The AAIB said the investigation into the crash is at an early stage and the factors that caused the helicopter to come down cannot yet be identified. Early indications show the flight approach of the Super Puma was normal until three miles from the airport runway and it crashed into the sea two miles west of runway 09 when airspeed dropped along with an "increased rate of descent," the AAIB said. "The evidence currently available suggests that the helicopter was intact and upright when it entered the water," a statement said. The Super Puma was travelling from the Borgsten Dolphin support vessel when it came down with 16 passengers and two crew on board. The victims have been named as Duncan Munro, 46, from Bishop Auckland, County Durham; George Allison, 57, from Winchester, Hampshire; Sarah Darnley, 45, from Elgin, Moray; and 59-year-old Gary McCrossan, from Inverness. Last Friday's crash was the fifth incident involving Super Pumas in the North Sea since 2009. In April 2009 an AS332 L2, operated by Bond, went down north east of Peterhead on its return from a BP platform, killing all 14 passengers and two crew on board. A fatal accident inquiry into the 2009 crash is expected to begin in Aberdeen next January.