The UK Civil Aviation Authority has hinted that the 23 August fatal accident off the Shetland Isles involving a Eurocopter AS332L2 Super Puma was not caused by "an airworthiness or technical problem".
Contained in a statement supporting the resumption of offshore flights with Super Puma helicopters, following a short-lived voluntary flight ban, the CAA says: "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.
"We would not allow a return to service unless we were satisfied that it was safe to do so. We will review the position if any new evidence comes to light."
Last week all Super Pumas - AS332L/L1s, L2s and EC225s - were voluntarily grounded by operators following the fatal crash in the sea 2nm (3.7km) from Sumburgh.
However, this restriction was lifted on 29 August by pan-industry body the Helicopter Safety Steering Group, which said it believed the helicopters were safe to fly.
This position is supported by the CAA. It says although the initial suspension was correct, talks with the Air Accidents Investigation Branch - which is probing the crash - helicopter operators and safety regulator EASA, plus a review and assessment of the "evidence available", led it to change its view.
However, the AAIB - which on 29 August recovered the combined flight data and cockpit voice recorder for the aircraft (G-WNSB) - says the investigation is ongoing and the cause of the accident "is yet to be determined".