The flight suspension on all four rotorcraft variants was eventually lifted Aug. 29 following a two-day meeting of the HSSG. However, the group says that, given the sensitivities around the accident, the AS332L2 should only initially return to non-revenue operations such as training.
The HSSG says it is “satisfied that there is no reason to believe there is an inherent mechanical problem with any of the AS332L/L1, AS332L2 or EC225 helicopter types.” CHC, which returned AS332L2s to operations outside the U.K. Aug 29, says: “From what we know so far about the Sumburgh incident, as well as tens of thousands of hours of experience with this aircraft, it is apparent there is not a fundamental problem with AS332L2 aircraft that led to this accident.”
But workers unions remain dissatisfied, saying that “workforce confidence in the Super Puma type aircraft was severely dented after the two ditching events of last year and the fatal accident in 2009.” They urge that the helicopters not restart operations until the cause of the Aug. 23 accident is found.
Operators and the British Airline Pilots Association (Balpa) have reaffirmed their confidence in the rotorcraft, urging oil workers not to judge it or draw early conclusions about the accident, since investigators have not yet reported the cause.
Twelve passengers and the two pilots managed to escape from the Super Puma within minutes after it ditched into the misty waters off Fitful Head at the southern tip of the Shetland Islands. The helicopter, registered as G-WNSB, was just minutes from landing at Sumburgh Airport after flying from the drilling platform Borgsten Dolphin on behalf of the oil firm Total when it apparently suffered a catastrophic loss of power, sending it tumbling into the sea.
Investigators say the approach to Sumburgh appeared normal until 3 mi. out, when the airspeed decreased and the helicopter descended rapidly. They believe the rotorcraft landed intact and upright, but rolled over in the water and was broken up by repeated contact with the rocky shoreline.
Within hours, emergency services recovered three bodies; a fourth was reportedly found still trapped within the helicopter's cabin. The wreckage of the rotorcraft has since been salvaged and brought aboard an oil and gas support ship, Bibby Polaris. The flight data recorder was found on Aug. 29.
Since the accident, Total has reportedly chartered several ships to conduct platform-crew change operations with the expectation that some workers will refuse to fly to platforms on any model of helicopter. Other companies extended staff rotation periods on platforms and reduced manning to minimum levels. Of the 16,000 people offshore at any one time, some 12,000 were affected by the disruption caused by the suspension.
Using ships is not a long-term solution: While helicopter transfer missions take just a couple of hours, ship transfers can take up to 10 times as long, and transiting passengers from vessel to platform presents its own dangers.