Tuesday, October 1, 2013
UK Civil Aviation Authority Probes Scottish AS332 Super Puma Crash
Following the fatal accident involving CHC AS332L2 Super Puma G-WNSB on August 23, UK operators returned their helicopters back to service in late August. Four out of 18 passengers died when the aircraft came down in the sea two miles short of Sumborough Airport on the Shetland Islands.
On Thursday, Aug. 29, CHC returned its Eurocopter AS332L2 Super Pumas to normal operational service to oil platforms in the North Sea. On the same day, Bond Offshore Helicopters returned its EC225 fleet to scheduled service with the caveat that it would only use its fleet of “crew change AS332L2s for non-passenger operations (maintenance, positioning and training flights).”
On August 30, the UK’s Civil Aviation Authority declared: “We have reviewed and assessed the evidence available, including the information already published by the Air Accident Investigation Branch and detailed information provided to us by the operators. Our team of specialists includes pilots who are experienced in flying the Super Puma AS332 L2 in the North Sea environment.”
“Based on all the information currently available, we do not believe that the accident was caused by an airworthiness or technical problem, and consider that the decision by the operators to resume Super Puma flights is appropriate. We would not allow a return to service unless we were satisfied that it was safe to do so. We will review the position if any new evidence comes to light.”
The Air Accident Investigations Branch (AAIB) has stated that the helicopter’s voice and data recorder has now been recovered for analysis.
On August 29, the AAIB declared: “Preliminary information indicates that the approach proceeded normally until approximately three miles from the runway when there was a reduction in airspeed accompanied by an increased rate of descent.”
At time of writing in mid-September, the Civil Aviation Authority had not released to cause of the crash.
The four fatalities have been named: Duncan Munro, 46, from Bishop Auckland; Sarah Darnley, 45, from Elgin; Gary McCrossan, 59, from Inverness; and George Allison, 57, from Winchester.
The AS332L2 accident has once again generated serious concerns regarding the safety of the Super Puma family of helicopters operating in the oil and gas sector in the North Sea.
Another fatal accident involving an AS332L2 occurred on April 1, 2009 at 12:55 pm, when a Bond-operated AS332L2 Super Puma (G-REDL) crashed into the sea [from around 2,000 feet] approximately 11 miles north-east of Peterhead, Scotland. Two crewmen and 14 passengers died in the accident with no survivors.
Last year, the EC225, the other member of the Super Puma family, was at the center of two ditching incidents in the North Sea. A report issued by the UK’s Air Accident Investigations Branch (AAIB) stated that an EC225 LP Super Puma (G-REDW) ditching 20 nm east of Aberdeen on May 10, 2012. This was followed just over five months later on Oct. 22, 2012 by an EC225 LP Super Puma (G-CHCN) [operated by CHC Scotia] ditching 32 nm southwest of Sumburgh, Shetland Islands. Soon after all EC225 operations were suspended.
The AAIB report stated: “On both G-REDW and G-CHCN the bevel gear vertical shaft fractured, leading to associated warnings of loss of main gearbox (MGB) oil pressure on the central warning panel (CWP).” Both aircraft had to immediately ditch. In each case, the 14 and 19 passengers and crew, respectively, were rescued.
Following the 2009 crash of the AS332L2, the AAIB Special Bulletin 5/2009, published on July 16, 2009, included the following Safety Recommendation (2009-075): “It is recommended that the European Aviation Safety Agency, in conjunction with Eurocopter, urgently review the design, operational life and inspection processes of the planet gears used in the epicyclic module of the main rotor gearbox installed in AS332L2 and EC225LP helicopters, with the intention of minimizing the potential of any cracks progressing to failure during the service life of the gears.”
On July 22 this year, Eurocopter announced: “A return to flight of EC225 helicopters suspended from service will begin this month following approval of the prevention and detection measures developed by Eurocopter for the twin-engine rotorcraft throughout its range of missions.” It went on to report that “the EASA regulatory authority [had] validated on July 10 these safety measures, which were developed by Eurocopter after an extensive investigation into the main gearbox shaft failures of two EC225 helicopters in the North Sea in 2012. EASA’s validation was followed by the U.K. Civil Aviation Authority’s lifting of operational restrictions on the same day, with the Civil Aviation Authority of Norway taking the step on July 19. This allows the full return to service of EC225s worldwide.”
The belief that any problem with the EC225 had been solved was confirmed through a statement by the newly appointed president and CEO of Eurocopter, Guillaume Faury: “I am convinced that the designed and approved measures are the right ones, allowing a safe return to service of the entire fleet... Eurocopter’s teams remain entirely mobilized to support our customers in the return to service and full availability of their EC225s.” —By Andrew Drwiega, International Bureau Chief
Group Vice President Corporate Communications, Cécile Vion-Lanctuit, issued the following statement, which is repeated in full: “An AS332 L2, operated by CHC Scotia, was involved in an accident on Friday, Aug. 23 at 6:20 pm, approximately two miles west of Sumburgh off Shetland.Guillaume Faury, Eurocopter’s CEO, said: ‘We all at Eurocopter are deeply saddened by this accident. This is a tragedy for all of us. We express our deepest sympathies to the families, friends and colleagues of those who lost their lives. Our thoughts are with all those affected, including the workforce in the North Sea. We also wish to acknowledge all those persons involved in the search and rescue operations. Their prompt and professional action saved many lives and for that we are sincerely thankful.’Members of Eurocopter’s senior management have arrived in Aberdeen to support in this very difficult time. At present, limited technical information is available regarding the cause of the accident. Eurocopter’s experts are in Aberdeen working closely with the investigation authorities to determine the cause.”
Step Change In Safety’s Helicopter Safety Steering Group (HSSG) met on August 24 to discuss the accident and express their condolences, releasing the following statement:“At present there are no confirmed facts as to the causes of this accident. As a result, the HSSG, supported by the Step Change in Safety Leadership Team, has taken the precautionary measure of recommending temporary suspension of all Super Puma commercial passenger flights to and from offshore oil and gas installations within the UK. This does not apply to the use of search and rescue helicopters for emergency response.The Super Puma series of helicopters includes the following variants: AS332 L, L1, L2 and EC225. There are significant technical differences between these variants; however, until more is understood on cause of the accident, this cautious approach is appropriate.HSSG will closely monitor the situation and will only recommend resumption of flights by one or more of the Super Puma variants when it considers that sufficient factual information is available to support the decision.”