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ASN Wikibase Occurrence # 75168
Last updated: 28 May 2020
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Date:16-JUL-2002
Time:19:44 UTC
Type:Silhouette image of generic S76 model; specific model in this crash may look slightly different
Sikorsky S-76A+
Owner/operator:Bristow Helicopters
Registration: G-BJVX
C/n / msn: 760100
Fatalities:Fatalities: 11 / Occupants: 11
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:near the Leman 49/26 Foxtrot platform in the North Sea -   United Kingdom
Phase: Approach
Nature:Non Scheduled Passenger
Departure airport:Clipper offshore installation, Sole Pitt field
Destination airport:Global Santa Fe Monarch MODU, Leman field
Narrative:
On the evening of the accident the aircraft departed Norwich to complete a scheduled flight consisting of six sectors in the southern North Sea offshore gas fields. The first four sectors were completed without incident but whilst en-route between the Clipper, an offshore production platform, and the Global Santa Fe Monarch, a drilling rig, the aircraft suffered a catastrophic structural failure. The helicopterís main rotor assembly separated almost immediately and the fuselage fell to the surface about 0.8 nm north-west of the Global Santa Fe Monarch which at the time was attached to the Leman 49/26 Foxtrot platform, a normally unmanned installation. Witnesses reported hearing a single or double muffled bang or boom, and seeing the aircraft fall into the sea. The fuselage disintegrated on impact and the majority of the structure sank. Fast rescue craft launched from the Putford Achilles, a multipurpose standby vessel, arrived at the scene of the accident within a few minutes. There were no survivors amongst the nine passengers and two crew.

The investigation identified the following causal factors:

i). A manufacturing anomaly created an area of reduced insulation between a main rotor bladeís spar and one section of its two-piece leading edge erosion cover.
ii). The affected blade had been struck by lightning.
iii). Electrical energy from the lightning strike exploited the manufacturing anomaly and caused microstructural damage that was not detectable when the blade was returned to its manufacturer for assessment.
iv). The blade was repaired before being returned to service and a fatigue crack in the spar originated from the microstructural damage.
v). An opaque protective patch applied to the erosion coverís scarf joint hid exterior symptoms of the developing spar crack that appeared before the accident.
vi). The helicopterís proprietary onboard Health and Usage Monitoring System (IHUMS) did not provide sufficient warning of impending blade failure in time to avert the accident.
vii). There were no in-flight symptoms of impending blade failure that the pilots should have recognised.

Six safety recommendations were made.

FAA airworthiness directive (FAA AD 202-15-51E) was promulgated on 26 July 2002.

Sources:

https://www.gov.uk/aaib-reports/s3-2002-sikorsky-s76-modified-g-bjvx-16-july-2002
https://www.gov.uk/aaib-reports/aar-1-2005-sikorsky-s-76a-g-bjvx-16-july-2002
https://publicapps.caa.co.uk/modalapplication.aspx?catid=1&pagetype=65&appid=11&mode=detail&id=1682

Safety recommendations:

Safety recommendation 2004-040 issued by AAIB to EASA


Revision history:

Date/timeContributorUpdates
17-Jun-2010 13:35 TB Added
21-Nov-2012 15:41 Dr. John Smith Updated [Time, Operator, Location, Departure airport, Destination airport, Source, Embed code, Narrative]
25-Nov-2012 12:32 TB Updated [Operator, Location, Nature, Departure airport, Destination airport, Source, Embed code, Narrative]
03-Aug-2014 18:41 Aerossurance Updated [Nature, Source, Narrative]
22-Jul-2016 14:43 Dr.John Smith Updated [Time, Location, Source, Narrative]
22-Jul-2016 14:47 Dr.John Smith Updated [Narrative]
28-Dec-2016 11:09 Aerossurance Updated [Time, Location, Departure airport, Destination airport, Source, Narrative]
28-Dec-2016 11:10 Aerossurance Updated [Narrative]

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