The crew of a helicopter which crashed off Sumburgh in 2013 killing four people failed to agree their planned approach to the isles.
A fatal accident inquiry has heard insufficient information was shared between the commander of the Super Puma L2 and the co-pilot over which mode of autopilot technology would be used.
On the fifth day of the inquiry, senior inspector for the Air Accident Investigation Branch (AAIB) Alison Campbell – herself an experienced pilot – said “no-one was minding the shop”.
The inquiry also heard the crew failed to adequately take account of weather and where they would fly to should conditions have prevented them from landing at Sumburgh.
She told Sheriff Principal Derek Pyle: “I think a lack of briefing on autopilot modes and how they were going to fly the approach was a major omission.”
“I think the commander clearly had in his mind what method he was going to use to fly the approach, and did so. But the co-pilot didn’t have a full picture of what the commander was going to do.
“In the co-pilot’s mind he was always playing catch-up. He was seeing what the commander was doing and thinking ‘that’s what he’s doing.’
“That makes it difficult to monitor your crew member because you’re always behind them.”
The inquiry has heard the pilot of the CHC-operated aircraft was flying in three-axis mode automatic pilot, which controls roll, pitch and yaw. But the pilot also had the option to fly in four-axis, which allows for automatic hover.
Ms Campbell said the crew were entitled to fly in three-axis, and make an attempt to land at Sumburgh.
But she told the inquiry the crew faced a “challenging situation” and were “almost certainly going to find themselves in cloud”.
“I think it was probably a very challenging day, weather-wise,” she said.
“Had it been me, I would have used all the automation that was available.”
Following the accident, the operator had changed standard operating procedures mandating the use of four-axis.
The inquiry has heard that a high rate of descent had developed during the approach to Sumburgh, leaving the helicopter at a “critically low energy state”.
Ms Campbell said the crew “talk about it” when the helicopter was at 460 feet – a point when it should have been above 700 feet.
“But there is no clear message that they realise they are significantly below the approach path.”
The inquiry is being held via the internet as a result of the coronavirus crisis.
Duncan Munro, 46, from Bishop Auckland; Sarah Darnley, 45, from Elgin; Gary McCrossan, 59, from Inverness; and George Allison, 57, from Winchester, all died in the crash.
This week it emerged the accident claimed a fifth victim in December 2017 when Samuel Bull, who had been one of the 18 passengers flying from the Borgsten Dolphin platform, died in London. An inquest recorded his death was by suicide.