ASN logo
ASN Wikibase Occurrence # 18540
Last updated: 14 September 2021
This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information. If you feel this information is incomplete or incorrect, you can submit corrected information.

Date:06-NOV-1986
Time:11:31 LT
Type:Silhouette image of generic H47 model; specific model in this crash may look slightly different
Boeing Vertol BV234LR Chinook (CH-47)
Owner/operator:British International Helicopters
Registration: G-BWFC
MSN: MJ004
Fatalities:Fatalities: 45 / Occupants: 47
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Category:Accident
Location:North Sea, 2.5 mi E of Sumburgh -   United Kingdom
Phase: Approach
Nature:Offshore
Departure airport:Brent Charlie Offshore Installation
Destination airport:Sumburgh, Shetland (LSI/EGPB)
Investigating agency: AAIB
Narrative:
Crashed into the North Sea when the forward transmission spiral bevel ring gear failed. This caused the rotor synchronisation to be lost and the aft rotors cut through the aircraft as it broke up in mid air. The underlying causes were the inadequacy of a previously accepted test program and the failure of a stringent inspection programme.

Only two of the 47 POB (44 passengers and 3 crew) survived.

The helicopter was normally based at Aberdeen Airport but had been based at Sumburgh Airport since 3 November 1986 to operate a shuttle service from the Shell Brent field in the East Shetland Basin. On 6 November the first flight was delayed due to an oil leak from an engine gearbox that was soon rectified and the aircraft left Sumburgh at 08:58 with 40 passengers for the Brent Field. The aircraft visited three platforms with exchanges of freight and passengers then departed Brent Platform C at 10:22 with 44 passengers on board for return to Sumburgh Airport. It transited at a height of 2,500 feet, and as it approached Sumburgh it was cleared to descend to 1,000 feet. Reporting 4.5 miles from the airfield, the controller cleared it to land on helicopter runway 24. Nothing else was heard.

The crew noticed an increased noise level in the flightdeck followed by a bang. Despite applying full cyclic pitch control the aircraft did not respond and nose-dived towards the sea from a height of 150 feet (50 m). The helicopter hit the sea, broke up and sank. A Coastguard search and rescue helicopter which had just departed Sumburgh Airport reported liferafts in the sea. It then observed a survivor clinging to a substantial piece of wreckage. While they winched the man on board another survivor was noted amongst the floating bodies. With no signs of other survivors the Coastguard helicopter flew the survivors to Lerwick for transfer to hospital.

The AAIB made three safety recommendations:

1) Certification procedures be reviewed so that all modifications to vital components are adequately scrutinised and tested before approval and more closely monitored after their introduction into service.

2) The Civil Aviation Authority should report on the progress that has been made towards the early incorporation of a specification for suitable condition monitoring systems into airworthiness requirements for helicopters and indicate the time scale and scope of likely developments.

3) Requirements relating to the ADELT (Automatically Deployable Location Transmitter) equipment, including location, crashworthiness, protection and power supplied, be reviewed in the light of the accident. (The beacon did not operate due to impact damage to the aft part of the aircraft.)

Sources:

https://www.pprune.org/rotorheads/468256-shetland-chinook-legacy-remembered.html
https://www.gov.uk/aaib-reports/2-1988-boeing-vertol-bv-234-lr-g-bwfc-6-november-1986
https://airfactsjournal.com/2020/04/i-survived-the-deadliest-helicopter-crash-in-european-history

Accident investigation:
cover
  
Investigating agency: AAIB
Status: Investigation completed
Duration:
Download report: Final report


Images:

Photo of G-BWFC courtesy AirHistory.net


Aberdeen - Dyce (EGPD / ABZ)
7 August 1984; (c) Fergal Goodman

Revision history:

Date/timeContributorUpdates
17-May-2008 11:10 ASN archive Added
02-Jan-2010 07:36 TB Updated [Time, Aircraft type, Other fatalities, Location, Phase, Nature, Departure airport, Destination airport, Source]
05-Apr-2010 05:42 TB Updated [Aircraft type]
15-Jan-2011 05:39 Anon. Updated [Narrative]
07-Jun-2012 03:24 TB Updated [Time, Source, Narrative]
24-Nov-2012 15:35 Dr. John Smith Updated [Source, Embed code, Narrative]
23-Dec-2012 09:04 TB Updated [Time, Source, Embed code, Narrative]
29-May-2013 13:43 Dr. John Smith Updated [Source, Embed code, Narrative]
30-Oct-2014 02:23 Dr. John Smith Updated [Destination airport, Embed code]
21-Jan-2016 20:47 Aerossurance Updated [Aircraft type, Location, Departure airport, Narrative]
11-May-2016 05:51 Anon. Updated [Departure airport]
17-Oct-2016 15:42 Aerossurance Updated [Time, Departure airport, Source, Narrative]
17-Oct-2016 15:45 Aerossurance Updated [Source]
17-Oct-2016 15:47 Aerossurance Updated [Source]
17-Oct-2016 15:49 Aerossurance Updated [Source]
01-Mar-2017 16:09 TB Updated [Location, Source]
27-Apr-2020 15:16 Aerossurance Updated [Location, Source]

Corrections or additions? ... Edit this accident description