Date:	Friday 29 April 2016
Time:	11:55 LT
Type:	Eurocopter EC 225LP Super Puma Mk2+
Owner/operator:	CHC Helikopter Service
Registration:	LN-OJF
MSN:	2721
Year of manufacture:	2009
Fatalities:	Fatalities: 13 / Occupants: 13
Aircraft damage:	Destroyed
Category:	Accident
Location:	Turøy just west of Sotra, near Bergen -   Norway
Phase:	En route
Nature:	Offshore
Departure airport:	Gullfaks B offshore installation
Destination airport:	Bergen-Flesland Airport (BGO/ENBR)
Investigating agency:	AIBN
Confidence Rating:	Information verified through data from accident investigation authorities

Narrative:
Flight HKS241 impacted the rocky shoreline of the Turøy Island, off Norway. All thirteen occupants were killed. The helicopter operated on a round trip from Bergen-Flesland Airport, Norway to the Gullfaks B offshore installation in the North Sea. A video shot by an eyewitness show the main rotor falling, separated from the helicopter.
The recordings on the CVFDR showed that everything appeared to be normal until a sudden catastrophic failure developed in 1-2 seconds. The CVFDR recordings ended abruptly at the same time.

Probable Cause : "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."

- CAA Norway issued a Safety Directive on 29 April 2016, followed by one from the UK CAA, temporarily prohibiting the use of the EC225LP for commercial air transport.
- An Emergency AD was issued by EASA on 3 May 2016 with a second on 1 June 16 regarding suspension bar fittings.
- The AIBN issued a first Preliminary Report on 13 May 2016 (updated 2 weeks later and a third on 1 June 16). Following the third an EASA Flight Prohibition AD was issued.
- On 7 October 2016 EASA replaced the Flight Prohibition AD with a new AD that removed one type of bearing and introduced extra maintenance checks.
- On 7 July 2017 it was announced the remaining operational directives would be lifted.
- The AIBN final report was issued 5 July 2018 with 12 recommendations.

https://gfx.nrk.no/RXL6AiBqdFbRuDwJp1WiIQPQbpWnljeUPqsHw2C6yjhA
https://www.abcnyheter.no/nyheter/2016/04/29/195213989/minst-13-personer-om-bord-i-ulykkeshelikopter-i-hordaland
http://www.aftenposten.no/nyheter/iriks/Helikopterstyrten-i-Hordaland---direkteblogg-8450661.html#xtor=RSS-3
https://www.nettavisen.no/nyheter/direkte-helikopterstyrten-i-hordaland/3423219023.html

Sept 2019: https://www.flightglobal.com/news/articles/airbus-helicopters-finds-root-cause-of-turoy-h225-cr-460792/

Data __________________________
https://www.flightradar24.com/data/aircraft/ln-ojf#98ee4bc
http://aerossurance.com/news/ec225-main-rotor-mgb-design/

Airbus Helicopters _______________________
http://www.airbus.com/helicopters/info-centre/ln-ojf-accident-investigation-status/norway-statement.html
https://www.airbus.com/helicopters/info-centre/ln-ojf-accident-investigation-status.html

CAA Norway (Luftfartstilsynet)_____________
https://translate.google.fr/translate?sl=auto&tl=en&js=y&prev=_t&hl=fr&ie=UTF-8&u=http%3A%2F%2Fwww.luftfartstilsynet.no%2Faktuelt%2FFlygeforbud_for_EC225LP&edit-text=&authuser=0
https://translate.google.fr/translate?hl=fr&sl=no&tl=en&u=http%3A%2F%2Fwww.luftfartstilsynet.no%2Faktuelt%2FHelikopter_har_styrtet_ved_Tur%C3%B8y_utenfor_Bergen1

EASA _______________________________
https://ad.easa.europa.eu/ad/2016-0089-E
https://ad.easa.europa.eu/ad/2016-0103-E
https://ad.easa.europa.eu/ad/2016-0104-E
https://ad.easa.europa.eu/ad/2016-0199

AIB-N ________________________________
https://www.aibn.no/Aviation/Investigations/16-286
https://www.aibn.no/About-us/Nyhetsarkiv/The-Helicopter-Accident-The-work-continues (1 May 16)
https://www.aibn.no/About-us/Nyhetsarkiv/The-Helicopter-Accident-Data-from-the-combined-FDR-and-CVR-retrieved-Data-is-of-good-quality_ (2 May 16)
https://www.aibn.no/About-us/Nyhetsarkiv/The-Helicopter-Accident-The-search-for-components-is-resumed (6 May 2016)
https://www.aibn.no/About-us/Nyhetsarkiv/The-Helicopter-Accident-Preliminary-report (13 May 16)
https://www.aibn.no/Aviation/Investigations/16-286 (updated preliminary report 27 May, 1 June and 28 June 16 and of 28 April 2017)
https://www.aibn.no/Aviation/Published-reports/2018-04 (Final Report 5 July 2018)

http://aerossurance.com/news/ec225-lnojf-investigation/
http://aerossurance.com/helicopters/as332l2-225-planet-gear/
http://aerossurance.com/helicopters/super-puma-epicyclic-gear-hm/
http://www.statoil.com/en/NewsAndMedia/News/2016/Pages/Report23Sept2016.aspx
http://www.caa.co.uk/News/Restrictions-on-H225LP-and-AS332L2-Super-Puma-helicopters-to-be-lifted(1)/

The Eurocopter EC225 that crashed near Bergen was flying from "Gullfaks B" oil platformhttps://t.co/a8Oiff3AqD pic.twitter.com/DFVaF0cjOH

— Flightradar24 (@flightradar24) 29 avril 2016

🇳🇴#AirbusHelicopters is confident that it has identified the root cause of the main gearbox (MGB) failure behind the fatal 2016 crash of an H225 in Norway.
ASN: https://t.co/PUoRgLepx0…
Press: https://t.co/sSkjThA3zb pic.twitter.com/LIVT6nF0n6

— PLANES OF LEGEND (@PlanesOfLegend) September 12, 2019

Date/time	Contributor	Updates
29-Apr-2016 11:58	whiteshark	Added
29-Apr-2016 12:01	whiteshark	Updated [Registration, Narrative]
29-Apr-2016 13:38	whiteshark	Updated [Narrative]
29-Apr-2016 13:47	Iceman 29	Updated [Embed code]
29-Apr-2016 14:10	Iceman 29	Updated [Cn, Embed code, Narrative]
29-Apr-2016 15:55	Iceman 29	Updated [Source, Embed code, Narrative, Photo, ]
29-Apr-2016 18:04	TB	Updated [Time, Aircraft type, Operator, Other fatalities, Nature, Source, Narrative]
29-Apr-2016 19:14	harro	Updated [Operator, Departure airport, Destination airport, Narrative]
29-Apr-2016 19:16	harro	Updated [Source, Narrative]
30-Apr-2016 18:18	AvidFlyer	Updated [Narrative]
30-Apr-2016 18:20	harro	Updated [Narrative]
30-Apr-2016 18:25	harro	Updated [Source]
01-May-2016 13:19	Aerossurance	Updated [Location, Departure airport, Source, Embed code, Narrative]
02-May-2016 13:51	Aerossurance	Updated [Source, Narrative]
02-May-2016 13:51	Aerossurance	Updated [Source, Narrative]
03-May-2016 21:30	Aerossurance	Updated [Source, Narrative]
06-May-2016 13:52	Aerossurance	Updated [Source]
13-May-2016 19:49	Aerossurance	Updated [Time, Source, Narrative]
14-May-2016 20:34	harro	Updated [Narrative]
23-May-2016 22:33	Aerossurance	Updated [Source, Narrative]
27-May-2016 15:31	Aerossurance	Updated [Source, Narrative]
01-Jun-2016 20:00	Aerossurance	Updated [Source, Narrative]
02-Jun-2016 17:03	Aerossurance	Updated [Source, Narrative]
08-Jun-2016 07:33	Anon.	Updated [Narrative]
28-Jun-2016 20:59	Aerossurance	Updated [Source, Narrative]
03-Jul-2016 10:44	Aerossurance	Updated [Embed code]
03-Jul-2016 11:12	Aerossurance	Updated [Source]
23-Sep-2016 10:22	Aerossurance	Updated [Source]
08-Oct-2016 06:25	Aerossurance	Updated [Source, Narrative]
10-Oct-2016 16:01	Anon.	Updated [Phase]
28-Apr-2017 11:04	Aerossurance	Updated [Phase, Source, Narrative]
29-Apr-2017 16:21	Aerossurance	Updated [Source]
07-Jul-2017 19:47	Aerossurance	Updated [Source, Narrative]
08-Jul-2017 00:24	Iceman 29	Updated [Embed code]
09-Oct-2017 17:01	Iceman 29	Updated [Embed code]
29-Apr-2018 09:06	Aerossurance	Updated [Source]
05-Jul-2018 16:22	Aerossurance	Updated [Source, Narrative]
07-Jul-2018 19:56	Captain Adam	Updated [Narrative]
12-Sep-2019 09:20	Iceman 29	Updated [Source, Embed code]
11-Sep-2020 18:37	harro	Updated [Embed code, Narrative, Accident report, Accident report, ]
11-Sep-2020 18:38	harro	Updated [Accident report, ]