Fresh doubts have been cast on the accuracy of a technical log for the Super Puma helicopter involved in the 2009 North Sea disaster.
According to pilots who flew the aircraft the day before the tragedy, on April 1, just 10 minutes passed between the engine being shut down and restarted.
As the fatal accident inquiry entered its 10th day, one of the team of mechanics at operator Bond questioned the time taken to do inspection work during a turnaround the day before.
One of the things the inquiry is trying to establish is whether the helicopter’s engines were running and its rotors turning when checks were carried out.
David Shand insisted the rotor blades could not have been running as the Super Puma AS332 L2 was still on “close monitoring” – meaning extra checks – after a metal fragment was found in its gearbox six days before.
But he was “surprised” that a gap of only 10 minutes was recorded by pilots as the time between the rotors stopping and restarting.
He added: “The aircraft was shut down. It would have had to be shut down.”
Some of the inspection work could have been done while the rotors were still running, but essential gearbox checks ordered after the discovery of the metal particle on March 25 could only be done after shutdown, he said.
Mr Shand said this work was done – perhaps by him, although he could not remember – and showed nothing unusual.
Another engineer, Torquil Allen, said it would normally take two people about eight and a half minutes for a routine turnaround inspection and up to 10 minutes more if additional “pre-flight” checks were required.
Mr Allen, 60, also said the extra checks of the gearbox for signs of more metal fragments could only be done if the rotors were off.
Last week, senior engineer James Gilmour, 57, questioned the accuracy of the log.
Mr Gilmour, Bond’s former engineering director and now an aviation consultant, said: “Ten minutes seems very tight. I would have thought you would at least need 15 minutes.”
The two pilots and all 14 passengers died after the helicopter plunged into the sea about 13 miles from Peterhead on April 1, 2009.
The inquiry continues.