The AAIB said that while “no causal technical failure” had been found, detailed examination of available data and of the wreckage was continuing.
The UK's Civil Aviation Authority, France's air accident authority and EU aviation safety officials are all also involved in the investigation, as are the manufacturers of the helicopter and its engines.
The AAIB said it has found that both engines were delivering power up to the moment of impact, when the AS332 L2 Super Puma helicopter crashed into the sea on approach to Sumburgh Airport in the Shetland Islands on 23 August.
Investigators
