A final report by air accident investigators into a North Sea helicopter crash which claimed four lives has made a series of recommendations for operators and pilots.
The Super Puma plunged into the sea off Shetland on August 23, 2013, with 18 people on board.
The crash claimed the life of George Allison, 57, who grew up in South Shields and also lived in Boldon and Jarrow and went on to live in Winchester, along with Duncan Munro, 46, from Bishop Auckland in County Durham, Sarah Darnley, 45, from Elgin, Moray, and Gary McCrossan, 59, from Inverness.
The helicopter was returning from the Borgsten Dolphin support vessel to Sumburgh Airport.
The measures include a requirement for pilots who are licensed to fly through bad weather to receive regular training on how to read the flight instruments which are specific to the type of helicopter being operated.
An initial report by the Air Accidents Investigation Branch (AAIB) had stated that the crew failed to notice their airspeed was decreasing until it was too late to avoid the crash.
No mechanical fault was discovered with the helicopter, the AAIB said.
Other AAIB recommendations include a requirement for helicopters which already must have cockpit voice recorders to also install devices to capture images.
They called for large helicopters certified for offshore operation to only have cabin seating layouts which would mean that in an emergency each exit would need to be used by no more than two passengers seated adjacent to it.
Companies operating helicopters to support the North Sea oil and gas industry were also urged to set up a programme to monitor flight data.
Following the impact with the water, the helicopter rolled upside down and rapidly filled with water, but did not sink due to two automatically inflated floats, the AAIB said.
Twelve passengers and two crew escaped and survived the crash.
Of the four that died, two failed to escape from the upturned fuselage and one was found floating on the surface of the water.
A fourth passenger did make their way onto a life raft but then died. A post-mortem examination found evidence of "significant" pre-existing heart disease.
A "check height" audio alert was sounded in the cockpit once the helicopter had fallen to 300 feet, the report noted.
The commander attempted to resolve the issue but "the situation was unrecoverable in the remaining height available", according to the inquiry.
The AAIB stated: "The evidence suggests that the appropriate flight instrument displays were not being monitored adequately in the latter stages of the approach."
One possible explanation given is that the 51-year-old commander - who "had a good training and operational record" - became focused on looking for visual references to aid landing.
A transcript of the final seconds before the crash reveals that the commander said: "Wow, what's going on here? Wow, wow, wow. Oh no, oh no. No, no, no."
He then let out an expletive before the impact occurred.
The British Airline Pilots Association issued a statement, saying: "Many safety improvements have already been made to helicopter operations since this tragic accident but pilots and safety experts will be examining the report to identify what more can be done to avoid a repeat.
"The challenge will be to drive up industry-wide standards at a time when the drive to reduce contract prices puts those standards under pressure."
Keith Conradi, AAIB's chief inspector of air accidents, said: "The final report follows an in-depth and careful investigation of the causal and contributory factors.
"This has led us to make a number of safety recommendations concerning improvements to operational procedures, training, offshore helicopter design requirements and the use of technology to prevent similar accidents in the future."