HOME

TheInfoList



OR:

On 29 April 2016, a CHC Helikopter Service Eurocopter EC225 Super Puma helicopter, carrying oil workers from the
Gullfaks B Gullfaks is an oil and gas field in the Norwegian sector of the North Sea operated by Equinor. It was discovered in 1978, in block 34/10, at a water depth of 130-230 meters.Petterson, O., Storli, A., Ljosland, E., Nygaard, O., Massie, I., and Carl ...
platform in the North Sea, crashed near Turøy, a Norwegian coastal island from the city of Bergen. The main rotor assembly detached from the aircraft and the fuselage plummeted to the ground, exploding on impact. All thirteen people on board were killed. The subsequent investigation concluded that a gear in the main rotor gearbox had failed due to a
fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...
crack that had propagated under-surface, escaping detection. Various safety recommendations were made, including for
Airbus Helicopters Airbus Helicopters SAS (formerly Eurocopter Group) is the helicopter manufacturer, helicopter manufacturing division of Airbus. It is the largest in the industry in terms of revenues and turbine helicopter deliveries. Its head office is located ...
, the current manufacturer of the type, to consider redesigning the affected gearbox.


Aircraft

The accident aircraft was an EC225LP Super Puma helicopter, manufactured by
Eurocopter Airbus Helicopters SAS (formerly Eurocopter Group) is the helicopter manufacturing division of Airbus. It is the largest in the industry in terms of revenues and turbine helicopter deliveries. Its head office is located at Marseille Provence Ai ...
(now named
Airbus Helicopters Airbus Helicopters SAS (formerly Eurocopter Group) is the helicopter manufacturer, helicopter manufacturing division of Airbus. It is the largest in the industry in terms of revenues and turbine helicopter deliveries. Its head office is located ...
), registration LN-OJF.


Background

At 10:05 local time ( UTC+2), HKS241 took off from Bergen's
Flesland Airport Bergen Airport ( nn, Bergen lufthamn; ), alternatively Bergen Flesland Airport or simply Flesland Airport, is an international airport located at Flesland in the city and municipality of Bergen, Vestland, Norway. Opened in 1955, it is the second ...
, five minutes behind schedule. It arrived at the
Gullfaks B Gullfaks is an oil and gas field in the Norwegian sector of the North Sea operated by Equinor. It was discovered in 1978, in block 34/10, at a water depth of 130-230 meters.Petterson, O., Storli, A., Ljosland, E., Nygaard, O., Massie, I., and Carl ...
platform on time and departed at 11:16, carrying two pilots and eleven passengers, employees and subcontractors of Norwegian oil company
Statoil Equinor ASA (formerly Statoil and StatoilHydro) is a Norwegian state owned enterprise, state-owned multinational energy company headquartered in Stavanger. It is primarily a petroleum company, petroleum company, operating in 36 countries with ad ...
. It was scheduled to land back at Flesland Airport at 12:08.


Crash

At 11:53, as the helicopter approached
Sotra Sotra or Store Sotra is the name of a large island in Øygarden Municipality in Vestland county, Norway, located just west of the city of Bergen. It is part of a pair of islands called 'Sotra' and 'Litlesotra' ('small Sotra') that are part of a ...
off the coast of Bergen, several witnesses observed the flight, stating that nothing was out of the ordinary until the sound suddenly changed and the helicopter started to sway. Moments later the main rotor assembly of the helicopter detached, causing a sudden drop in speed and altitude, as confirmed by flight telemetry. With all control lost, it crashed on the islet of Skitholmen between the islands of Turøy and Toftøy at 11:54:35 local time and exploded on impact. Most of the wreckage then slid off the islet into the sea. A video recording of the detached main rotors spinning to earth was made shortly afterwards. The rotor came to rest several hundred metres away on the island of Toftøy. According to flight tracking data, the time between the detachment of the rotor and the crash itself was only eleven seconds, with the helicopter diving in that time.


Response

At 11:55, local police received reports of a helicopter crash. Six minutes later, at 12:01, this was relayed to the national rescue service. Rescue workers, police and fire fighters arrived at the scene at 12:20, and the wreckage was located partially submerged soon after. At 13:15, authorities confirmed that the wreckage had been found, and that they did not expect to find survivors. Norwegian Prime Minister Erna Solberg described the crash as "horrible". King Harald V and Queen Sonja cancelled a visit to Sweden that was to have marked King Carl XVI Gustaf's 70th birthday.


Crew and passengers

On its final flight the aircraft was carrying eleven passengers and two pilots. Authorities confirmed that eleven of the people on board were Norwegian, with one British passenger and one Italian crew member. The eleven passengers were employees of six different companies: Halliburton (four employees); Aker Solutions (three); and one employee each of
Statoil Equinor ASA (formerly Statoil and StatoilHydro) is a Norwegian state owned enterprise, state-owned multinational energy company headquartered in Stavanger. It is primarily a petroleum company, petroleum company, operating in 36 countries with ad ...
,
Schlumberger Schlumberger Limited (), doing business as SLB, is an oilfield services company. Schlumberger has four principal executive offices located in Paris, Houston, London, and The Hague. Schlumberger is the world's largest offshore drilling compa ...
, Welltec and . On 2 May the names of all the crash victims were released.


Investigation

The Norwegian Accident Investigation Board (AIBN) is responsible for investigating aviation accidents in Norway. The British Air Accidents Investigation Branch (AAIB) and French Bureau d'Enquêtes et d'Analyses pour la Sécurité de l'Aviation Civile (BEA) each dispatched a team of investigators to Norway to assist the AIBN in its investigation. Representatives from Airbus Helicopters and engine manufacturer Turbomeca were part of the BEA team. The European Aviation Safety Agency (EASA) also participated in the investigation. The aircraft's combined cockpit voice recorder (CVR) and flight data recorder (FDR) was sent to the AAIB in the United Kingdom for data retrieval. Data were successfully downloaded on 1 May and sent back to the AIBN which confirmed that the received data were of good quality and useful for further investigation. On 1 May, the BBC reported that the helicopter had been forced to land on 26 April, over fears of a technical problem after a cockpit warning light had illuminated a few minutes into a flight. In a press conference on 3 May, the AIBN stated that the initial investigation and analysis of data from the combined FDR and CVR convinced them that pilot error could be ruled out and that there were no indications of any malfunction until one second before the end of the recording, which they assumed was the moment when the rotor detached. An AIBN spokesman said the accident was down to a technical fault and "not an accident caused by human error". Later that day Airbus Helicopters updated their press release bulletin with a request for verification of the correct installation of all main gearbox suspension bar attachments for the EC225LP. They also stated that "similar measures will be published shortly for the EC725AP in a specific ASB" (Alert Service Bulletin). Within a week of the accident, an underwater sled with magnets had been developed and deployed to find small critical metal fragments from gearbox and bearings to support the investigations. On 27 May the AIBN confirmed that scenarios under consideration included failure of epicyclic module, suspension bar (lift strut) attachment and MGB (gearbox) conical housing. On the same day Airbus Helicopters updated their press release bulletin and stated that in their opinion only failure of the attachment of a suspension bar could be assessed as probable based on the information available by that date, an opinion also stated by Airbus during a safety meeting on 20 May. On 1 June the AIBN released an update to the preliminary investigation report including an urgent safety recommendation to the European Aviation Safety Agency. The recommendation was based on metallurgical examinations where signs of fatigue in parts of the second stage planet gear were found. The gearbox had suffered "unkind treatment" (road accident) during transport in Australia, and was repaired before being mounted in LN-OJF. On 15 June, Airbus requested operators to check for metal residue in oil and to report unusual gearbox events. On 28 June the AIBN released a new preliminary report where they stated that the most likely cause to the accident was a
fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...
fracture in one of the second stage planet gears. They had not yet determined what initiated the fracture. AIBN draws similarity to the
2009 Bond Helicopters Eurocopter AS332 crash Just before 2:00 pm on 1 April 2009, Bond Offshore Helicopters Flight 85N crashed north-east of Peterhead, Scotland in the North Sea while returning from a BP oil platform in the Miller oilfield, north-east of Peterhead. The crash ki ...
, also caused by a gearbox fracture. Whereas particles had been detected in the Scottish gearbox's oil prior to the crash, no such indication was present for the Norwegian gearbox. , AIBN continued investigations with no indication of when a conclusion could be made. Also in February 2017, EASA issued a notice for operators to investigate the oil cooler for 16NCD13 alloy from the gearbox. On 28 April 2017 the AIBN released a new preliminary report with an update of the investigation progress one year after the accident. In this report they stated that the accident was a result of a fatigue fracture in one of the eight second stage planet gears in the epicyclic module of the main rotor gearbox and that the crack initiation appeared to be a surface micro-pit. The origin of the micro-pit was considered unknown at the time when the report was published. Also unknown is whether the fracture occurred momentarily or over several flight hours, and whether fracture fragments were spalled for detection by maintenance systems as happened in G-REDL. The issue is related to the airworthiness certificate of the aircraft. On 5 July 2018 the AIBN released the final report, they determined the cause as the following: The accident was a result of a fatigue fracture in a second stage planet gear in the epicyclic module of the main rotor gearbox. Cracks initiated from a micro-pit at the surface and developed subsurface to a catastrophic failure without being detected. 12 recommendations were made, one of the recommendations stated that Airbus should take another look at the design of the main gearbox of the Super Puma. By September 2019, Airbus had replicated the root cause in testing.


Aftermath

Shortly after the accident oil companies and helicopter operators voluntarily grounded 130 similar helicopters until further notice, except for aircraft being used for
search and rescue Search and rescue (SAR) is the search for and provision of aid to people who are in distress or imminent danger. The general field of search and rescue includes many specialty sub-fields, typically determined by the type of terrain the search ...
purposes. This was later followed by a grounding by the
Civil Aviation Authority of Norway Norwegian Civil Aviation Authority ( no, Luftfartstilsynet) is the Norwegian inspectorate responsible for civil aviation in Norway. It is subordinate to the Norwegian Ministry of Transport and Communications. Its head office is located in Bodø a ...
, specified to public transport flights and commercial air transport operations with EC225LP helicopters. Later that day the British
Civil Aviation Authority A civil aviation authority (CAA) is a national or supranational statutory authority that oversees the regulation of civil aviation, including the maintenance of an aircraft register. Role Due to the inherent dangers in the use of flight vehicles, ...
issued a Safety Directive which grounded all EC225LP helicopters on the United Kingdom Civil Aircraft Register, or flying in United Kingdom airspace, except for aircraft being used for search and rescue purposes. On 30 April,
Airbus Helicopters Airbus Helicopters SAS (formerly Eurocopter Group) is the helicopter manufacturer, helicopter manufacturing division of Airbus. It is the largest in the industry in terms of revenues and turbine helicopter deliveries. Its head office is located ...
issued a Safety Information Notice expressing their support of the decision to put all commercial passenger flights with Super Puma helicopters of model EC225LP "on hold". Other versions of the Super Puma were not included in this decision. On 1 May Airbus Helicopters stated in a press release that "Considering the additional information gathered during the last 48 hours, Airbus Helicopters' decision, at this stage, is to not suspend flights of any nature for the EC225LP". They did not specify the nature of the additional information leading to this decision. On 11 May the Norwegian Civil Aviation Authority and the UK Civil Aviation Authority jointly agreed to extend the grounding, now also including Super Puma helicopters of model AS332L2. The decision was based on similarities between the two helicopter models. On 2 June the Norwegian Civil Aviation Authority and the UK Civil Aviation Authority extended the grounding of EC225LP and AS332L2 helicopters, now also including search and rescue flights. The updated directives were results of a recommendation in the preliminary report published by the AIBN on 1 June. Later that day the European Aviation Safety Agency decided to prohibit all flights with EC225LP and AS332L2 helicopters in Europe. On 3 June the US Federal Aviation Administration (FAA) issued a directive prohibiting flights with EC225LP and AS332L2 helicopters. The similar military Eurocopter AS532 Cougar and Eurocopter EC725 of Germany and Brazil were grounded around 7 June in response to the accident, and the South Korean
Surion The KAI KUH-1 Surion is a twin-engine, transport utility helicopter developed primarily by Korea Aerospace Industries (KAI), Agency for Defense Development (ADD) and Korea Aerospace Research Institute (KARI) jointly with Eurocopter. In 2006, ...
was grounded in July 2016. A Surion with similar rotor and gearbox suffered rotor separation in 2018. By July 2016, 80% of the world fleet was on ground. The French military continued to operate its fleet.
Statoil Equinor ASA (formerly Statoil and StatoilHydro) is a Norwegian state owned enterprise, state-owned multinational energy company headquartered in Stavanger. It is primarily a petroleum company, petroleum company, operating in 36 countries with ad ...
, who had contracted the helicopter in the crash, permanently ceased use of the Super Puma family of helicopters, even after some restrictions were lifted, and stated their plans were instead to use the
Sikorsky S-92 The Sikorsky S-92 is an American twin-engine medium-lift helicopter built by Sikorsky Aircraft Sikorsky Aircraft is an American aircraft manufacturer based in Stratford, Connecticut. It was established by aviation pioneer Igor Sikorsky in 1 ...
helicopter to replace the Super Puma in contracts going forward. , the H225 remains grounded in the U.K. and Norway, and some had returned to service in Asia. By 2019, 51 were used mostly for utility. A claim by the widow of the British passenger for compensation under the Consumer Protection Act 1987 for a defective gearbox and helicopter is being pursued against the gearbox manufacturer Schaeffler and Airbus, led by Hugh James, solicitors of Cardiff and Balfour Manson of Edinburgh. As of June 2021, a settlement out of court has been reached between Airbus and the next of kin; all the next of kin have received compensation.


See also

Other North Sea helicopter incidents: *
1986 British International Helicopters Chinook crash On 6 November 1986, a Boeing-Vertol Model 234LR Chinook helicopter returning workers from the Brent oilfield crashed on approach to land at Sumburgh Airport in the Shetland Islands. At from the runway the helicopter had a catastrophic forw ...
*
Bristow Helicopters Flight 56C Bristow Helicopters Flight 56C was a helicopter flight that flew between Aberdeen and the Brae Alpha oil rig in the North Sea. On 19 January 1995, the AS 332L Super Puma helicopter operating the route, registered G-TIGK and named ''Cullen'', w ...
(1995) *
Helikopter Service Flight 451 On 8 September 1997 Flight 451, a Eurocopter AS 332L1 Super Puma, from the Norwegian helicopter operator Helikopter Service, crashed into the Norwegian Sea, northwest of Brønnøysund, Norway. The aircraft was en route from Brønnøysund Ai ...
(1997) * Bond Offshore Helicopters Flight 85N (2009)


References


External links


Investigation of helicopter accident at Turøy near Bergen in Hordaland county, Norway
AIBN
Helikopterstyrten i Hordaland
– detailed information about the accident
EC225 LN-OJF Accident Investigation Timeline
– Aerossurance
EC225 Main Rotor Head and Main Gear Box Design
– Aerossurance
Page
on Aviation Safety Network {{DEFAULTSORT:2016 Turoy helicopter crash 2016 in Norway April 2016 events in Europe Aviation accidents and incidents in 2016 Accidents and incidents involving helicopters Aviation accidents and incidents in Norway Fjell History of Vestland Øygarden Petroleum industry in Norway 2016 disasters in Norway