An investigation into a North Sea helicopter crash which killed four oil workers has so far found no evidence of technical failure.
Three men and a woman died when a Super Puma plunged into the sea off Shetland on August 23. There were 14 survivors.
"To date, no evidence of a causal technical failure has been identified; however, detailed examination of the CVFDR (combined voice and flight data recorder) data and the helicopter wreckage is continuing," the Air Accidents Investigation Branch said in a report.
The helicopter was travelling from the Borgsten Dolphin support vessel when it came down en route to Sumburgh Airport 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.
The AAIB said that both the helicopter's engines were giving out power when the aircraft hit the water.
It said that data downloaded from the black box on Sunday showed that the flight approach of the Super Puma was normal until three miles from the airport. At two miles it was below its correct path.
The report said: "The rate of descent remained constant for a period, before increasing rapidly.
"Shortly thereafter the helicopter, which was intact, struck the sea in a near level pitch attitude with a slight right bank.
"Both engines were delivering power until impact."