Eurocopter faces an uphill struggle to convince oil industry workers that its EC225 is safe to fly, even if the UK Civil Aviation Authority revokes its ban on overwater use of the type.
Jake Molloy, regional organiser for the Rail Maritime and Transport trade union, says offshore staff have been left angry and frustrated by the 22 October ditching of a CHC Scotia-operated EC225 (G-CHCN), which came barely five months after a similar incident.
It is the "carbon copy" nature of the second ditching that has left oil field workers so incensed, he says. "[In May] we were given countless assurances by Eurocopter that they had identified the problem and it was a manufacturing defect on a small batch of [bevel gear vertical] shafts.
"But we have had a repeat event, and its only through the grace of God that it happened on a benign weather day, otherwise we would have been counting body bags here," he says.
Eurocopter has yet to come up with a modification that would allow the grounded aircraft to resume operations. Even if they are cleared for service by the regulator, Molloy says the airframer will have to "rebuild confidence" in its aircraft.
"There are a lot of questions to be answered, they are going to have to justify everything about these shafts," he says.
Molloy is also critical of the European Aviation Safety Agency's approach to the issue, believing its remedy of increased vigilance of the type's vibration monitoring system to offer an unacceptable level of risk.
Eurocopter officials met with operators on 8 November to advise them of updates with its investigation. It has additionally been invited to the next meeting of the Helicopter Safety Steering Group - an oil industry body which includes union representatives - on 15 November.
Meanwhile, in a safety information notice issued on 2 November, the manufacturer confirms that the emergency lubrication system on the helicopter involved in the latest ditching appears to have been working. This suggests, as was the case in the May incident, that the warning system had again generated a false alarm indicating a failure of the back-up lubrication mechanism.
Alongside the EC225s, operators had grounded a number of AS332 helicopters. These are now being released back into service as Eurocopter retrofits the older variants with shafts unaffected by the safety issue.